xsim (19may17)

git-svn-id: svn://tug.org/texlive/trunk@44430 c570f23f-e606-0410-a88d-b1316a301751

84 files changed, 10586 insertions, 1 deletions

diff --git a/Master/texmf-dist/doc/latex/xsim/README b/Master/texmf-dist/doc/latex/xsim/README
new file mode 100644
index 00000000000..b8da799ff7d
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/README
@@ -0,0 +1,83 @@
+--------------------------------------------------------------------------
+XSIM 2017/05/19 v0.8a
+
+  eXercise Sheets IMproved
+
+--------------------------------------------------------------------------
+Clemens Niederberger
+Web:    https://github.com/cgnieder/xsim
+E-Mail: contact@mychemistry.eu
+--------------------------------------------------------------------------
+Copyright 2017 Clemens Niederberger
+
+This work may be distributed and/or modified under the
+conditions of the LaTeX Project Public License, either version 1.3
+of this license or (at your option) any later version.
+The latest version of this license is in
+  http://www.latex-project.org/lppl.txt
+and version 1.3 or later is part of all distributions of LaTeX
+version 2005/12/01 or later.
+
+This work has the LPPL maintenance status `maintained'.
+
+The Current Maintainer of this work is Clemens Niederberger.
+--------------------------------------------------------------------------
+The xsim package consists of the code files:
+   xsim.sty
+   xsimverb.sty
+   xsim.base.code.tex
+   xsim.blanks.code.tex
+   xsim.collections.code.tex
+   xsim.definitions.code.tex
+   xsim.environments.code.tex
+   xsim.exercises.code.tex
+   xsim.goals.code.tex
+   xsim.grades.code.tex
+   xsim.interface.code.tex
+   xsim.modules.code.tex
+   xsim.properties.code.tex
+   xsim.random.code.tex
+   xsim.solutions.code.tex
+   xsim.tags.code.tex
+   xsim.templates.code.tex
+   xsim.translations.code.tex
+   xsim.verbwrite.code.tex
+--------------------------------------------------------------------------
+The xsim package consists of the documentation files:
+   README
+   xsim.history, xsim.ideas
+   xsim_manual.tex, xsim_manual.pdf
+   xsim-manual.cls
+--------------------------------------------------------------------------
+The xsim package consists of the example files:
+   xsim.blanks.tex, xsim.blanks.pdf
+   xsim.boxed-headings.tex, xsim.boxed-headings.pdf
+   xsim.code-and-output.tex, xsim.code-and-output.pdf
+   xsim.collections.tex, xsim.collections.pdf
+   xsim.crossref.tex, xsim.crossref.pdf
+   xsim.description-list.tex, xsim.description-list.pdf
+   xsim.different-point-types.tex, xsim.different-point-types.pdf
+   xsim.difficulties.tex, xsim.difficulties.pdf
+   xsim.floating.tex, xsim.floating.pdf
+   xsim.grade-distribution.tex, xsim.grade-distribution.pdf
+   xsim.listings.tex, xsim.listings.pdf
+   xsim.multiplechoice.tex, xsim.multiplechoice.pdf
+   xsim.pointsums.tex, xsim.pointsums.pdf
+   xsim.randomexercises.tex, xsim.randomexercises.pdf
+   xsim.various.tex, xsim.various.pdf
+   xsim.texsx-199360.tex, xsim.texsx-199360.pdf
+   xsim.texsx-299534.tex, xsim.texsx-299534.pdf
+   xsim.texsx-305110.tex, xsim.texsx-305110.pdf
+   xsim.texsx-338165.tex, xsim.texsx-338165.pdf
+   xsim.texsx-350028.tex, xsim.texsx-350028.pdf
+   xsim.texsx-369065.tex, xsim.texsx-369065.pdf
+   xsim.texsx-369803.tex, xsim.texsx-369803.pdf
+   xsim.texsx-369686.tex, xsim.texsx-369686.pdf
+   xsim.texwelt-6698.tex, xsim.texwelt-6698.pdf
+   xsim.texwelt-15093.tex, xsim.texwelt-15093.pdf
+   xsim.golatex-16824.tex, xsim.golatex-16824.pdf
+   xsim.golatex-18844.tex, xsim.golatex-18844.pdf
+--------------------------------------------------------------------------
+If you have any ideas, questions, suggestions or bugs to report, please
+feel free to contact me.
+--------------------------------------------------------------------------
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.blanks.pdf b/Master/texmf-dist/doc/latex/xsim/examples/xsim.blanks.pdf
new file mode 100644
index 00000000000..dd26d671570
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.blanks.pdf
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.blanks.tex b/Master/texmf-dist/doc/latex/xsim/examples/xsim.blanks.tex
new file mode 100644
index 00000000000..b479e961c2c
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.blanks.tex
@@ -0,0 +1,23 @@
+\documentclass{article}
+\usepackage[utf8]{inputenc}
+\usepackage[ngerman]{babel}
+
+\usepackage{xsim,lipsum,xcolor}
+
+\xsimsetup{
+  solution/print = true ,
+  blank/filled-style = \underline{\textcolor{red}{#1}}
+}
+
+\begin{document}
+
+\begin{exercise}[points=3]
+  Erklären Sie den Begriff.
+
+  \blank[width=4\linewidth,linespread=1.5]{}
+\end{exercise}
+\begin{solution}
+  \blank[width=4\linewidth,linespread=1.5]{Die Lösung hier soll rot sein.}
+\end{solution}
+
+\end{document}
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.boxed-headings.pdf b/Master/texmf-dist/doc/latex/xsim/examples/xsim.boxed-headings.pdf
new file mode 100644
index 00000000000..99ba5bbc2a6
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.boxed-headings.pdf
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.boxed-headings.tex b/Master/texmf-dist/doc/latex/xsim/examples/xsim.boxed-headings.tex
new file mode 100644
index 00000000000..9ff47d9d992
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.boxed-headings.tex
@@ -0,0 +1,30 @@
+\documentclass{article}
+
+\usepackage{tcolorbox}
+\usepackage{xsim}    
+\usepackage{needspace}
+
+\DeclareExerciseEnvironmentTemplate{custom}
+  {%
+    \Needspace*{5\baselineskip}
+    \begin{tcolorbox}
+      \textbf{\XSIMmixedcase{\GetExerciseName}~\GetExerciseProperty{counter}.}%
+      \GetExercisePropertyT{subtitle}{ \textit{#1}}%
+    \end{tcolorbox}
+    \noindent
+  }
+  {\vspace{\baselineskip}}
+
+\xsimsetup{exercise/template = custom}
+
+\usepackage{lipsum}
+
+\begin{document}
+
+\begin{exercise}[subtitle=Foo bar baz]
+  \lipsum[1]
+\end{exercise}
+
+\lipsum[2]
+
+\end{document}
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.code-and-output.pdf b/Master/texmf-dist/doc/latex/xsim/examples/xsim.code-and-output.pdf
new file mode 100644
index 00000000000..bbbcfbc18a7
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.code-and-output.pdf
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.code-and-output.tex b/Master/texmf-dist/doc/latex/xsim/examples/xsim.code-and-output.tex
new file mode 100644
index 00000000000..f753f13939e
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.code-and-output.tex
@@ -0,0 +1,53 @@
+\documentclass{article}
+\usepackage{xsimverb,listings,xcolor}
+
+\lstdefinestyle{mystyle}{
+  language = [AlLaTeX]TeX ,
+  basicstyle = \ttfamily ,
+  columns = fullflexible ,
+  commentstyle = \color{gray!70} ,
+  keywordstyle = \color{red!70!black}
+}
+
+\makeatletter
+\NewDocumentEnvironment{example}{o}
+  {%
+    \XSIMgobblechars{2}%
+    \XSIMsetfilebegin{\@percentchar\space file `\jobname.tmp'}%
+    \XSIMsetfileend{\@percentchar\space bye bye}%
+    \IfNoValueTF{#1}
+      {\XSIMfilewritestart*{\jobname.tmp}}
+      {\XSIMfilewritestart{\jobname.tmp}}%
+  }
+  {%
+    \XSIMfilewritestop
+    \lstinputlisting[style=mystyle]{\jobname.tmp}%
+    \input{\jobname.tmp}
+  }
+
+\NewDocumentEnvironment{code}{o}
+  {%
+    \XSIMgobblechars{2}%
+    \IfNoValueTF{#1}
+      {\XSIMfilewritestart*{\jobname.tmp}}
+      {\XSIMfilewritestart{\jobname.tmp}}%
+  }
+  {%
+    \XSIMfilewritestop
+    \lstinputlisting[style=mystyle]{\jobname.tmp}%
+  }
+\makeatother
+
+\begin{document}
+
+\begin{example}
+  bla bla \LaTeX
+\end{example}
+
+\bigskip
+
+\begin{code}
+  blubber \LaTeX
+\end{code}
+
+\end{document}
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.collections.pdf b/Master/texmf-dist/doc/latex/xsim/examples/xsim.collections.pdf
new file mode 100644
index 00000000000..fd785cc0574
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.collections.pdf
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.collections.tex b/Master/texmf-dist/doc/latex/xsim/examples/xsim.collections.tex
new file mode 100644
index 00000000000..beca1910055
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.collections.tex
@@ -0,0 +1,62 @@
+\documentclass{article}
+\usepackage{xsim}
+
+\DeclareExerciseCollection{foo-easy}
+\DeclareExerciseCollection{foo-medium}
+\DeclareExerciseTagging{difficulty}
+
+\usepackage{filecontents,lipsum}
+\begin{filecontents*}{foo.tex}
+\begin{exercise}[difficulty=easy,points=1]
+  foo one \lipsum[4]
+\end{exercise}
+\begin{solution}
+  foo one \lipsum[4]
+\end{solution}
+\begin{exercise}[difficulty=medium,points=1]
+  foo two \lipsum[4]
+\end{exercise}
+\begin{solution}
+  foo two \lipsum[4]
+\end{solution}
+\begin{exercise}[difficulty=easy,points=1]
+  foo three \lipsum[4]
+\end{exercise}
+\begin{solution}
+  foo three \lipsum[4]
+\end{solution}
+\end{filecontents*}
+
+\begin{document}
+
+\begin{exercise}
+  outside before
+\end{exercise}
+
+\collectexercises{foo-easy}
+\xsimsetup{difficulty=easy}
+\input{foo.tex}
+\collectexercisesstop{foo-easy}
+% collection `foo-easy' now contains all exercises of file `foo.tex' tagged
+% with `difficulty=easy'
+
+\collectexercises{foo-medium}
+\xsimsetup{difficulty=medium}
+\input{foo.tex}
+\collectexercisesstop{foo-medium}
+% collection `foo-medium' now contains all exercises of file `foo.tex'
+% tagged with `difficulty=medium'
+
+\section{Easy}
+\printcollection{foo-easy}
+
+\section{Medium}
+\printcollection{foo-medium}
+
+\printsolutions[difficulty=medium]
+
+\section{All Exercises and Their Solutions Again, in Order of Appearance}
+
+\printcollection[print=both]{all exercises}
+
+\end{document}
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.crossref.pdf b/Master/texmf-dist/doc/latex/xsim/examples/xsim.crossref.pdf
new file mode 100644
index 00000000000..8151a0cef3f
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.crossref.pdf
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.crossref.tex b/Master/texmf-dist/doc/latex/xsim/examples/xsim.crossref.tex
new file mode 100644
index 00000000000..fa2fbbb509d
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.crossref.tex
@@ -0,0 +1,60 @@
+\documentclass{article}
+\usepackage{xsim,lipsum,hyperref}
+
+\DeclareExerciseHeadingTemplate{custom}
+  {\section{\XSIMtranslate{default-heading}}}
+
+\DeclareExerciseEnvironmentTemplate{custom}
+  {%
+    \IfInsideSolutionTF
+      {\label{sol:\ExerciseID}}
+      {\label{ex:\ExerciseID}}
+    \subsection*
+      {%
+        \XSIMmixedcase{\GetExerciseName}%
+        \IfInsideSolutionTF
+          {
+            to \GetExerciseParameter{exercise-name}%
+            ~\GetExerciseProperty{counter}%
+          }
+          {%
+            ~\GetExerciseProperty{counter}
+            \GetExercisePropertyT{subtitle}
+              { {\normalfont\itshape\PropertyValue}}%
+          }%
+      }
+    \noindent\llap{%
+      \footnotesize\sffamily
+      \IfInsideSolutionTF
+        {%
+          \XSIMmixedcase{\GetExerciseParameter{exercise-name}}
+          on page~\pageref{ex:\ExerciseID}.%
+        }
+        {%
+          \XSIMmixedcase{\GetExerciseParameter{solution-name}}
+          on page~\pageref{sol:\ExerciseID}.%
+        }%
+      \hspace*{\marginparsep}%
+    }%
+  }
+  {}
+\xsimsetup{
+  exercise/template = custom ,
+  solution/template = custom ,
+  print-solutions/headings-template = custom
+}
+
+\begin{document}
+
+\section{Exercises}
+\begin{exercise}
+  \lipsum[4]
+\end{exercise}
+\begin{solution}
+  \lipsum[4]
+\end{solution}
+
+\clearpage
+\printsolutions
+
+\end{document}
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.description-list.pdf b/Master/texmf-dist/doc/latex/xsim/examples/xsim.description-list.pdf
new file mode 100644
index 00000000000..d506ad960bc
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.description-list.pdf
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.description-list.tex b/Master/texmf-dist/doc/latex/xsim/examples/xsim.description-list.tex
new file mode 100644
index 00000000000..f3c9ed6d74f
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.description-list.tex
@@ -0,0 +1,42 @@
+\documentclass{article}
+\usepackage{xsim,lipsum}
+
+\DeclareExerciseEnvironmentTemplate{item}
+  {\item[\XSIMmixedcase{\GetExerciseName}~\GetExerciseProperty{counter}]}
+  {}
+\xsimsetup{
+  exercise/template=item,
+  solution/template=item,
+  print-solutions/headings-template=none
+}
+
+\newenvironment{exercises}
+  {\section{Exercises}\description}
+  {\enddescription}
+
+\newenvironment{solutions}
+  {\section{Solutions}\description}
+  {\enddescription}
+  
+\begin{document}
+
+\begin{exercises}
+  \begin{exercise}
+    \lipsum[4]
+  \end{exercise}
+  \begin{solution}
+    \lipsum[3]
+  \end{solution}
+  \begin{exercise}
+    \lipsum[12]
+  \end{exercise}
+  \begin{solution}
+    \lipsum[23]
+  \end{solution}
+\end{exercises}
+
+\begin{solutions}
+  \printsolutions
+\end{solutions}
+
+\end{document}
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.different-point-types.pdf b/Master/texmf-dist/doc/latex/xsim/examples/xsim.different-point-types.pdf
new file mode 100644
index 00000000000..b1de5d63253
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.different-point-types.pdf
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.different-point-types.tex b/Master/texmf-dist/doc/latex/xsim/examples/xsim.different-point-types.tex
new file mode 100644
index 00000000000..0ac35367760
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.different-point-types.tex
@@ -0,0 +1,52 @@
+\documentclass{article}
+\usepackage{xsim}
+
+\DeclareExerciseGoal{A}
+\DeclareExerciseGoal{C}
+\DeclareExerciseGoal{E}
+
+\newcommand*\printA{\TotalExerciseGoal{A}{~A~point}{~A~points}}
+\newcommand*\printC{\TotalExerciseGoal{C}{~C~point}{~C~points}}
+\newcommand*\printE{\TotalExerciseGoal{E}{~E~point}{~E~points}}
+
+\usepackage{needspace}
+\DeclareExerciseEnvironmentTemplate{custom}
+  {%
+    \par\vspace{\baselineskip}
+    \Needspace*{2\baselineskip}
+    \noindent
+    \textbf{\GetExerciseProperty{counter}}%
+    \IfExercisePropertySetT{subtitle}
+      { \textit{\GetExerciseProperty{subtitle}}} %
+    \IfInsideSolutionF{%
+      \marginpar{%
+        (\IfExercisePropertySetTF{E}{\GetExerciseProperty{E}}{0}/%
+         \IfExercisePropertySetTF{C}{\GetExerciseProperty{C}}{0}/%
+         \IfExercisePropertySetTF{A}{\GetExerciseProperty{A}}{0})%
+      }%
+    }%
+  }
+  {}
+\xsimsetup{
+  exercise/template = custom ,
+  solution/template = custom
+}
+\renewcommand*\theexercise{\arabic{exercise}.}
+
+\begin{document}
+
+Reachable: \printA, \printC, and \printE.
+
+\begin{exercise}[E=1]
+  Differentiate $y=3x^2+5x+3$.
+\end{exercise}
+
+\begin{exercise}[E=2,C=1]
+  Find the equation of the tangent line to the function $y=x/2$ at $x=2$.
+\end{exercise}
+
+\begin{exercise}[C=1,A=2]
+  Prove that the derivative of a constant is zero.
+\end{exercise}
+
+\end{document}
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.difficulties.pdf b/Master/texmf-dist/doc/latex/xsim/examples/xsim.difficulties.pdf
new file mode 100644
index 00000000000..846f19e2012
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.difficulties.pdf
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.difficulties.tex b/Master/texmf-dist/doc/latex/xsim/examples/xsim.difficulties.tex
new file mode 100644
index 00000000000..02712f15d66
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.difficulties.tex
@@ -0,0 +1,53 @@
+\documentclass{article}
+
+\usepackage[clear-aux]{xsim}
+\DeclareExerciseTagging{difficulty}
+\xsimsetup{
+  difficulty={easy,hard}
+}
+
+\DeclareExerciseEnvironmentTemplate{custom}
+  {
+    \subsection*
+      {%
+        \XSIMmixedcase {\GetExerciseName}\nobreakspace
+        \GetExerciseProperty{counter}%
+        \IfExercisePropertySetT{difficulty}
+          { {\normalfont(\GetExerciseProperty{difficulty})}}%
+        \IfInsideSolutionF{%
+          \IfExercisePropertySetT{subtitle}
+            { {\normalfont\itshape\GetExerciseProperty{subtitle}}}%
+        }%
+      }%
+    \IfExercisePropertySetT{points}
+      {%
+        \marginpar
+          {%
+            \IfInsideSolutionF{\rule{1.2cm}{1pt}\slash}%
+            \GetExerciseProperty{points}%
+            \IfExercisePropertySetT{bonus-points}
+              {\nobreakspace(+\GetExerciseProperty{bonus-points})}
+            \nobreakspace\XSIMtranslate{point-abbr}%
+          }%
+      }%
+  }
+  {}
+
+\xsimsetup{exercise/template = custom}
+
+\begin{document}
+
+\begin{exercise}[difficulty=easy]
+  An easy question.
+\end{exercise}
+\begin{exercise}[difficulty=medium]
+  This one's a bit harder.
+\end{exercise}
+\begin{exercise}[difficulty=hard]
+  Now let’s see if you can solve this one.
+\end{exercise}
+\begin{exercise}[difficulty=medium]
+  This is medium but printed anyway
+\end{exercise}
+
+\end{document}
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.floating.pdf b/Master/texmf-dist/doc/latex/xsim/examples/xsim.floating.pdf
new file mode 100644
index 00000000000..e2e96537ef1
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.floating.pdf
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.floating.tex b/Master/texmf-dist/doc/latex/xsim/examples/xsim.floating.tex
new file mode 100644
index 00000000000..08448df35a6
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.floating.tex
@@ -0,0 +1,50 @@
+% floating exercises:
+\documentclass{article}
+\usepackage{xsim,newfloat,caption,lipsum}
+
+\DeclareFloatingEnvironment[
+  fileext=loe,
+  listname={List of Exercises},
+  name=Exercise,
+  placement=htp,
+]{ex}
+
+\DeclareExerciseEnvironmentTemplate{float}
+  {%
+    \ex
+    \captionsetup{labelformat=empty,singlelinecheck=false,listformat=empty}
+    \IfExercisePropertySetTF{subtitle}{%
+      \XSIMexpandcode{%
+        \noexpand\caption{%
+          \noexpand\textbf{%
+            \XSIMmixedcase{\GetExerciseName}\nobreakspace
+            \GetExerciseProperty{counter}%
+          }: \GetExerciseProperty{subtitle}%
+        }%
+      }%
+    }{%
+      \caption{%
+        \textbf{%
+          \XSIMmixedcase{\GetExerciseName}\nobreakspace
+          \GetExerciseProperty{counter}%
+        }%
+      }%
+    }%
+  }
+  {\endex}
+
+\xsimsetup{exercise/template = float}
+
+\begin{document}
+
+\listofexs
+
+\begin{exercise}
+  \lipsum[4]
+\end{exercise}
+
+\begin{exercise}[subtitle=Let's have a look]
+  \lipsum[4]
+\end{exercise}
+
+\end{document}
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.golatex-16824.pdf b/Master/texmf-dist/doc/latex/xsim/examples/xsim.golatex-16824.pdf
new file mode 100644
index 00000000000..76cf1617cbd
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.golatex-16824.pdf
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.golatex-16824.tex b/Master/texmf-dist/doc/latex/xsim/examples/xsim.golatex-16824.tex
new file mode 100644
index 00000000000..3a324d4221f
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.golatex-16824.tex
@@ -0,0 +1,131 @@
+% http://golatex.de/schueler-und-lehrerloesung-im-gleichen-texfile-t16824.html
+\documentclass[fontsize=12pt,parskip=half]{scrartcl}
+\usepackage[utf8]{inputenc}
+\usepackage[T1]{fontenc}
+\usepackage[ngerman]{babel}
+
+\newlength\breite
+\setlength\breite{160mm}
+\newlength\hoehe
+\setlength\hoehe{80mm}
+
+\usepackage[
+  hdivide={3.0cm,\breite,},
+  vdivide={2.2cm,,2.2cm}]{geometry}
+\usepackage[bitstream-charter]{mathdesign}
+
+\usepackage[babel]{microtype}
+
+\usepackage[inline]{enumitem}
+
+\usepackage{amsmath,siunitx}
+\sisetup{
+  locale = DE ,
+  per-mode = fraction
+}
+
+\usepackage{xsim,needspace,tikz,tcolorbox}
+
+\xsimsetup{
+  exercise/template = gitter ,
+  solution/template = gitter
+}
+
+\DeclareExerciseEnvironmentTemplate{gitter}
+  {%
+    \IfInsideSolutionT{%
+      \tcolorbox[
+        detach title ,
+        title        = Lösung: ,
+        before upper = {\tcbtitle\space} ,
+        fonttitle    = \bfseries ,
+        fontupper    = \large ,
+        valign       = center ,
+        colframe     = black!50!white ,
+        colback      = black!12!white ,
+        coltext      = blue ,
+        coltitle     = blue ,
+        height       = \hoehe ,
+        width        = \breite ,
+        sharp corners
+      ]
+    }%
+  }
+  {%
+    \IfInsideSolutionTF
+      {\endtcolorbox}
+      {%
+        \IfSolutionPrintF{%
+        \par
+        \begin{tikzpicture}[semitransparent]
+          \draw[step=4mm, line width=0.15mm, black!60!white] (0,0) grid
+            (\breite,\hoehe);
+        \end{tikzpicture}
+        \par
+        }
+      }%
+  }
+
+\begin{document}
+
+\begin{exercise}
+  Für die \textbf{Schülerausgabe} sollen Häuschen (Grid) mit Seitenlänge
+  \SI{4}{\mm} gesetzt werden.
+\end{exercise}
+\begin{solution}
+  Hier soll die Lösung stehen: $E=m\cdot c^2$.
+\end{solution}
+
+\xsimsetup{solution/print=true}
+
+\begin{exercise}
+  Für die \textbf{Lehrerausgabe} sollen statt Häuschen die Lösung in
+  z.\,B. einer Box geschrieben werden. Dafür soll die Lösung (bezogen auf
+  dieses Beispiel) auch in einer Box mit der exakten Breite \SI{160}{\mm} und
+  der exakten Höhe \SI{80}{\mm} gesetzt werden. Weiter soll natürlich die
+  Position der Lösungsbox und der Häuschenbox exakt identisch sein.
+\end{exercise}
+\begin{solution}
+  Hier soll die Lösung stehen: $E=m\cdot c^2$.
+\end{solution}
+
+\clearpage
+
+\begin{exercise}
+  Beschreiben Sie die \textbf{Satzgruppe des Pythagoras}.
+\end{exercise}
+\begin{solution}
+  \begin{align*}
+    \left.\begin{aligned}
+      c^2   &=a^2+b^2\\
+      a^2   &=p\cdot c\;\wedge\; b^2=q\cdot c\\
+      h^2   &=p\cdot q
+    \end{aligned}\right\}
+    \begin{gathered}
+      \text{Satzgruppe}\\
+      \text{des Pythagoras}
+    \end{gathered}
+  \end{align*}
+\end{solution}
+
+\begin{exercise}
+  Geben Sie die Formel der \textbf{gleichförmigen Bewegung} wieder. Gehen Sie
+  davon aus, dass Sie 1000~Meter in
+  \SI[parse-numbers=false]{3\frac{1}{2}}{Minuten} laufen.
+  \begin{enumerate*}[label=\bfseries\alph*)]
+    \item Mit welcher Geschwindigkeit legen Sie die Strecke zurück?
+    \item Geben Sie die Geschwindigkeit in \si{\km\per\hour} an.
+  \end{enumerate*}
+  \textbf{Hinweis:} Nehmen Sie zur Berechnung die vereinfachte Form und gehen
+  Sie davon aus, dass Ihre Geschwindigkeit konstant ist.
+\end{exercise}
+\begin{solution}
+  \begin{align*}
+    s    &=v\cdot t+s_0 \\
+    1000 &=v\cdot 210 \\
+    v    &=\frac{\SI{1000}{\m}}{\SI{210}{\second}} \\
+    v    &=\SI{4.76}{\m\per\second} = \SI{17.1}{\km\per\hour}
+  \end{align*}
+\end{solution}
+
+\end{document}
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.golatex-18844.pdf b/Master/texmf-dist/doc/latex/xsim/examples/xsim.golatex-18844.pdf
new file mode 100644
index 00000000000..97cb4659e06
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.golatex-18844.pdf
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.golatex-18844.tex b/Master/texmf-dist/doc/latex/xsim/examples/xsim.golatex-18844.tex
new file mode 100644
index 00000000000..aa49dd64e1b
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.golatex-18844.tex
@@ -0,0 +1,94 @@
+% http://golatex.de/aufgabe-loesungs-umgebung-t18844.html
+\documentclass[18pt,a4paper]{article}
+\usepackage[utf8]{inputenc}
+\usepackage[ngerman]{babel}
+
+\usepackage{xsim,tcolorbox}
+\usepackage{amsmath}
+\xsimsetup{
+  exercise/within = section ,
+  exercise/the-counter = \thesection.\arabic{exercise} ,
+  print-solutions/headings-template=none
+}
+\SetExerciseParameters{exercise}{
+  exercise-template = mine ,
+  solution-template = mine
+}
+
+\DeclareExerciseEnvironmentTemplate{mine}
+  {%
+    \tcolorbox[
+      % colors:
+      colback = white , colframe = black , coltitle = black ,
+      % rules:
+      boxrule = 0pt , toprule = 1pt , bottomrule = 1pt , arc = 0pt ,
+      % spacing:
+      boxsep = 0pt , left = 0pt , right = 0pt ,
+      % title:
+      detach title , before upper = \tcbtitle\par\noindent ,
+      fonttitle = \bfseries ,
+      title = \XSIMmixedcase{\GetExerciseName}~\GetExerciseProperty{counter}
+    ]
+  }
+  {\endtcolorbox}
+
+\DeclareExerciseTranslation{German}{exercise}{Aufgabe}
+\DeclareExerciseTagging{difficulty}
+
+\begin{document}
+
+\section{Wellenausbreitung im Vakuum und in Materie}
+\subsection{Maxwellsche Gleichungen}
+
+\begin{align*}
+  \nabla \cdot \vec{E}\left(\vec{r}, t \right) =
+    \frac{\varrho\left(\vec{r}, t \right)}{\varepsilon_0}
+\end{align*}
+
+\begin{exercise}[difficulty=easy]
+Something stupid
+\end{exercise}
+\begin{solution}
+Here is a nonstupid solution for your problem
+\end{solution}
+
+\subsection{Empirischer Zugang zu Wellengleichungen}
+
+\begin{exercise}[difficulty=hard]
+Eine weitere Aufgabe
+\end{exercise}
+\begin{solution}
+Solution Number 2
+\end{solution}
+
+\subsection*{Lösungen}
+\printsolutions[section,difficulty=hard]
+
+\section{Wellenausbreitung im Vakuum und in Materie}
+\subsection{Maxwellsche Gleichungen}
+
+\begin{align*}
+  \nabla \cdot \vec{E}\left(\vec{r}, t \right) =
+    \frac{\varrho\left(\vec{r}, t \right)}{\varepsilon_0}
+\end{align*}
+
+\begin{exercise}[difficulty=easy]
+Something stupid
+\end{exercise}
+\begin{solution}
+Here is a nonstupid solution for your problem
+\end{solution}
+
+\subsection{Empirischer Zugang zu Wellengleichungen}
+
+\begin{exercise}[difficulty=hard]
+Eine weitere Aufgabe
+\end{exercise}
+\begin{solution}
+Solution Number 2
+\end{solution}
+
+\subsection*{Lösungen}
+\printsolutions[section]
+
+\end{document}
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.grade-distribution.pdf b/Master/texmf-dist/doc/latex/xsim/examples/xsim.grade-distribution.pdf
new file mode 100644
index 00000000000..248358c4a16
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.grade-distribution.pdf
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.grade-distribution.tex b/Master/texmf-dist/doc/latex/xsim/examples/xsim.grade-distribution.tex
new file mode 100644
index 00000000000..8e9731de24d
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.grade-distribution.tex
@@ -0,0 +1,56 @@
+\documentclass{article}
+\usepackage{xsim}
+
+\xsimsetup{grades/split=;}
+
+\DeclareGradeDistribution{
+  1   = 1 ;
+  1,5 = .9167 ;
+  2   = .8333 ;
+  2,5 = .75 ;
+  3   = .6667 ;
+  3,5 = .5833 ;
+  4   = .5
+}
+
+\begin{document}
+
+\begin{exercise}[points=4]
+\end{exercise}
+
+\begin{exercise}[points=4]
+\end{exercise}
+
+\begin{exercise}[points=4]
+\end{exercise}
+
+\begin{exercise}[points=4,bonus-points=10]
+\end{exercise}
+
+\begin{exercise}[points=4]
+\end{exercise}
+
+\begin{exercise}[points=4]
+\end{exercise}
+
+
+\goalsforgrade{points + bonus-points}{1,5}
+\goalsforgrade{points+bonus-points}{2}
+
+\pointsforgrade{1}
+\pointsforgrade{1,5}
+\pointsforgrade{2}
+\pointsforgrade{2,5}
+\pointsforgrade{3}
+\pointsforgrade{3,5}
+\pointsforgrade{4}
+
+\totalgoalforgrade{1}
+\totalgoalforgrade{1,5}
+\totalgoalforgrade{2}
+\totalgoalforgrade{2,5}
+\totalgoalforgrade{3}
+\totalgoalforgrade{3,5}
+\totalgoalforgrade{4}
+
+\end{document}
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.listings.pdf b/Master/texmf-dist/doc/latex/xsim/examples/xsim.listings.pdf
new file mode 100644
index 00000000000..0d388f2c708
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.listings.pdf
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.listings.tex b/Master/texmf-dist/doc/latex/xsim/examples/xsim.listings.tex
new file mode 100644
index 00000000000..6dd302feb09
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.listings.tex
@@ -0,0 +1,48 @@
+% http://tex.stackexchange.com/questions/131546/
+\documentclass{article}
+
+\usepackage{xcolor}
+\usepackage{listings}
+\usepackage{xsim}
+
+\lstset{
+  frame=single,
+  xleftmargin=20pt,
+  numbers=left,
+  numberstyle=\small,
+  tabsize=2,
+  breaklines,
+  showspaces=false,
+  showstringspaces=false,
+  language=C,
+  basicstyle=\small\ttfamily,
+  commentstyle=\itshape\color{gray}
+}
+
+\begin{document}
+
+\begin{exercise}[points=6]
+Consider the following C program.
+\begin{lstlisting}
+#include <stdio.h>
+
+int main(int argc, char *argv[]) {
+  printf("hello, world\n");
+}
+\end{lstlisting}
+\end{exercise}
+\begin{solution}
+Consider the following C program.
+\begin{lstlisting}
+#include <stdio.h>
+
+int main(int argc, char *argv[]) {
+  printf("hello, world\n");
+}
+\end{lstlisting}
+\end{solution}
+
+\pagebreak
+\printsolutions 
+
+\end{document}
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.multiplechoice.pdf b/Master/texmf-dist/doc/latex/xsim/examples/xsim.multiplechoice.pdf
new file mode 100644
index 00000000000..02dac6c4df9
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.multiplechoice.pdf
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.multiplechoice.tex b/Master/texmf-dist/doc/latex/xsim/examples/xsim.multiplechoice.tex
new file mode 100644
index 00000000000..e0db3eb0c52
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.multiplechoice.tex
@@ -0,0 +1,70 @@
+\documentclass{scrartcl}
+\usepackage[clear-aux]{xsim}
+
+\usepackage{enumitem,amssymb,fmtcount}
+\newlist{choices}{itemize}{1}
+\setlist[choices]{label=$\Box$}
+\newcommand*\choice{\item}
+
+\DeclareExerciseProperty{choices}
+\DeclareExerciseProperty*{multiple}
+\DeclareExerciseEnvironmentTemplate{mc}
+  {%
+    \UseExerciseTemplate{begin}{default}%
+    \IfExerciseBooleanPropertyTF{multiple}
+      {Select one or more correct answers}
+      {%
+        \GetExercisePropertyT{choices}
+          {Select \numberstringnum{#1} correct answer\ifnum#1>1 s\fi.}%
+      }%
+    \begin{choices}
+  }
+  {%
+    \end{choices}
+    \UseExerciseTemplate{end}{default}%
+  }
+
+\DeclareExerciseType{mc}{
+  exercise-env = multiplechoice ,
+  solution-env = correctchoices ,
+  exercise-name = Question ,
+  solution-name = Solution ,
+  exercise-template = mc ,
+  solution-template = mc ,
+  counter = exercise
+}
+
+\xsimsetup{
+  exercise/name = Question ,
+  solution/name = Solution
+}
+
+\begin{document}
+
+\section{Questions}
+\begin{multiplechoice}[choices=1]
+  \choice one
+  \choice two
+  \choice three
+  \choice four
+\end{multiplechoice}
+
+\begin{exercise}
+  Answer this question on a separate sheet.  
+\end{exercise}
+
+\begin{multiplechoice}[multiple]
+  \choice one
+  \choice two
+  \choice three
+  \choice four
+\end{multiplechoice}
+
+\begin{multiplechoice}[choices=2]
+  \choice one
+  \choice two
+  \choice three
+  \choice four
+\end{multiplechoice}
+
+\end{document}
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.pointsums.pdf b/Master/texmf-dist/doc/latex/xsim/examples/xsim.pointsums.pdf
new file mode 100644
index 00000000000..aa822a1bd7a
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.pointsums.pdf
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.pointsums.tex b/Master/texmf-dist/doc/latex/xsim/examples/xsim.pointsums.tex
new file mode 100644
index 00000000000..29d7ac0cdc1
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.pointsums.tex
@@ -0,0 +1,30 @@
+\documentclass{article}
+\usepackage{xsim,lipsum}
+
+\NewDocumentCommand\printcompletepoints{}{%
+  \TotalExerciseGoals{points + bonus-points}
+    {\,\XSIMtranslate{point}}
+    {\,\XSIMtranslate{points}}%
+}
+
+\NewDocumentCommand\pointsandbonus{}{%
+  \TotalExerciseGoal{points}{}{}%
+  \IfExerciseGoalsSumTF{bonus-points}{=0}
+    {}
+    {\,(+\,\TotalExerciseGoal{bonus-points}{}{})}%
+  \,\XSIMtranslate{points}%
+}
+
+\begin{document}
+
+\begin{exercise}[points=3,bonus-points=1]
+  \lipsum[4]
+\end{exercise}
+
+\begin{exercise}[points=8,bonus-points=3]
+  \lipsum[4]
+\end{exercise}
+
+\printtotalpoints\ vs.\@ \printcompletepoints\ vs.\@ \pointsandbonus
+
+\end{document}
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.randomexercises.pdf b/Master/texmf-dist/doc/latex/xsim/examples/xsim.randomexercises.pdf
new file mode 100644
index 00000000000..773d34f495b
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.randomexercises.pdf
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.randomexercises.tex b/Master/texmf-dist/doc/latex/xsim/examples/xsim.randomexercises.tex
new file mode 100644
index 00000000000..60877b1a4ab
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.randomexercises.tex
@@ -0,0 +1,58 @@
+\documentclass{article}
+\usepackage{xsim}
+
+\DeclareExerciseCollection{foo}
+
+\usepackage{filecontents}
+\begin{filecontents*}{random.tex}
+\begin{exercise}[ID=A]
+  exercise A
+\end{exercise}
+\begin{solution}
+  solution A
+\end{solution}
+\begin{exercise}[ID=B]
+  exercise B
+\end{exercise}
+\begin{solution}
+  solution B
+\end{solution}
+\begin{exercise}[ID=C]
+  exercise C
+\end{exercise}
+\begin{solution}
+  solution C
+\end{solution}
+\begin{exercise}[ID=D]
+  exercise D
+\end{exercise}
+\begin{solution}
+  solution D
+\end{solution}
+\begin{exercise}[ID=E]
+  exercise E
+\end{exercise}
+\begin{solution}
+  solution E
+\end{solution}
+\begin{exercise}[ID=F]
+  exercise F
+\end{exercise}
+\begin{solution}
+  solution F
+\end{solution}
+\end{filecontents*}
+
+\begin{document}
+
+\collectexercises{foo}
+\input{random.tex}
+\collectexercisesstop{foo}
+
+\section*{Exercises}
+\printrandomexercises[collection=foo,exclude=D]{3}
+
+\section*{Solutions}
+\printsolutions*
+
+\end{document}
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-199360.pdf b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-199360.pdf
new file mode 100644
index 00000000000..94925495985
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-199360.pdf
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-199360.tex b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-199360.tex
new file mode 100644
index 00000000000..334275140ab
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-199360.tex
@@ -0,0 +1,60 @@
+% http://tex.stackexchange.com/a/199360/
+\documentclass{scrartcl}
+\usepackage[clear-aux]{xsim}
+
+\usepackage{tcolorbox,blindtext}
+
+\DeclareExerciseEnvironmentTemplate{custom}
+  {%
+    \begin{tcolorbox}[
+      width = \textwidth ,
+      colbacktitle = \IfInsideSolutionTF{green}{red} ,
+      coltitle = black ,
+      title = {\XSIMmixedcase{\GetExerciseName}~\GetExerciseProperty{counter}}]}
+  {\end{tcolorbox}}
+
+\xsimsetup{
+  exercise/template = custom ,
+  solution/template = custom
+}
+
+\begin{document}
+
+\begin{exercise}
+  First Question
+\end{exercise}
+\begin{solution}
+  Yes, it's a question
+\end{solution}
+
+\begin{exercise}[print=false,use]
+  Question: What is special about Brontosaurs?
+\end{exercise}
+\begin{solution}
+  They are thin at one end, thick in the middle and thin on the end again
+\end{solution}
+
+\begin{exercise}
+  Proof 
+\begin{equation}
+  a^2 + b^2 = c^2
+\end{equation}
+\end{exercise}
+\begin{solution}
+  to be done
+\end{solution}
+
+\begin{exercise}
+  Cite a Latin Text
+\end{exercise}
+\begin{solution}
+  \textcolor{blue}{\blindtext}
+\end{solution}
+
+\begin{exercise}
+  \textcolor{red}{\textbf{Cite a Latin text again}}
+\end{exercise}
+
+\printsolutions*
+
+\end{document}
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-299534.pdf b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-299534.pdf
new file mode 100644
index 00000000000..c006aeb34c3
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-299534.pdf
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-299534.tex b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-299534.tex
new file mode 100644
index 00000000000..1c2be46df39
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-299534.tex
@@ -0,0 +1,32 @@
+% http://tex.stackexchange.com/q/299534/
+\documentclass{article}
+\usepackage{pythontex}
+\usepackage{xsim}
+
+\begin{document}
+
+\section{Test}
+
+\begin{exercise}[subtitle = Codeless Question,points=10]
+  A question without code, worth 10 points. Subtitle and point values are in
+  correct place.
+\end{exercise}
+\begin{solution}
+  Solution 1
+\end{solution}
+
+\begin{exercise}[subtitle = Codeful Question,points=15]
+Now with PythonTeX:
+\begin{pyblock}
+print("hello, world!")
+sum = 0
+for j in range(0,100):
+    sum += j
+print(sum)
+\end{pyblock}
+\end{exercise}
+\begin{solution}
+  Solution 2
+\end{solution}
+
+\end{document}
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-305110.pdf b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-305110.pdf
new file mode 100644
index 00000000000..fb92e875a91
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-305110.pdf
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-305110.tex b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-305110.tex
new file mode 100644
index 00000000000..c10928da0ce
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-305110.tex
@@ -0,0 +1,67 @@
+% https://tex.stackexchange.com/q/305110
+\documentclass[12pt, a4paper]{book}
+\usepackage{xsim}
+
+\xsimsetup{
+  exercise/within = section ,
+  exercise/the-counter = \thesection.\arabic{exercise}
+}
+
+\begin{document}
+\part{EXCERCISES}
+\chapter{Topic 1}
+
+\section{Section}
+
+\begin{exercise}
+  I'm an excercise.
+\end{exercise}
+\begin{solution}
+  I'm a solution.
+\end{solution}
+
+\section{Section}
+
+\begin{exercise}
+  I'm an excercise.
+\end{exercise}
+\begin{solution}
+  I'm a solution.
+\end{solution}
+
+\chapter{Topic 2}
+
+\section{Section}
+\begin{exercise}
+  I'm an excercise.
+\end{exercise}
+\begin{solution}
+  I'm a solution.
+\end{solution}
+
+\section{Section}
+\begin{exercise}
+  I'm an excercise.
+\end{exercise}
+\begin{solution}
+  I'm a solution.
+\end{solution}
+
+\setcounter{chapter}{0}
+\part{SOLUTIONS}
+
+\chapter{Topic 1}
+\section{Section}
+\printsolutions[chapter=1,section=1]
+
+\section{Section}
+\printsolutions[chapter=1,section=2]
+
+\chapter{Topic 2}
+\section{Section}
+\printsolutions[chapter=2,section=1]
+
+\section{Section}
+\printsolutions[chapter=2,section=2]
+
+\end{document}
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-338165.pdf b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-338165.pdf
new file mode 100644
index 00000000000..f6557530a1d
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-338165.pdf
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-338165.tex b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-338165.tex
new file mode 100644
index 00000000000..e48d8880dab
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-338165.tex
@@ -0,0 +1,72 @@
+% http://tex.stackexchange.com/q/338165
+\documentclass{article}
+\usepackage[T1]{fontenc}
+\usepackage{leading,microtype}
+\usepackage[french]{babel}
+
+\usepackage{tasks}
+\usepackage{xsim}
+\usepackage{tcolorbox}
+\tcbuselibrary{breakable, skins}
+\settasks{
+  counter-format = tsk.
+}
+
+\DeclareExerciseEnvironmentTemplate{boxed}
+  {%
+    \tcolorbox[
+      enhanced ,
+      attach boxed title to top center = {yshift=-7.5pt} ,
+      colback = white , colbacktitle = white ,
+      coltitle = black , colframe = black ,
+      boxed title style = { colframe = white } ,
+      fonttitle=\bfseries,
+      sharp corners=all,
+      breakable,
+      title=
+        \XSIMmixedcase{\GetExerciseName}%
+        \IfInsideSolutionF{%
+          ~\GetExerciseProperty{counter}%
+          \IfExercisePropertySetT{subtitle}{: \GetExerciseProperty{subtitle}}%
+        }%
+    ]
+  }
+  {\endtcolorbox}
+
+\xsimsetup{
+  exercise/template = boxed ,
+  solution/template = boxed ,
+  solution/print =  true
+}
+
+\leading{15pt}
+
+\newcommand*\complement{\overline}
+\newcommand*\union{\cup}
+\newcommand*\intersection{\cap}
+\newcommand*\set[1]{\{#1\}}
+
+\begin{document}
+
+\begin{exercise}[subtitle=Set Calculus]
+  Soient $E=\set{1,2,3,4,5,6,7}$ et $A$, $B$, $C$ et $D$ quatre parties de E
+  d\'efinies par $A=\set{1,2,3,4}$, $B=\set{4,5,6,7}$, $C=\set{1,3,5,7}$ et
+  $D=\set{2,3,4,5,6}$.
+  \begin{tasks}(2)
+    \task Calculer $\complement{A}$.
+    \task Calculer $(A\union B) \intersection (C\union D)$.
+    \task Calculer $(A\intersection B) \union (C\intersection D)$.
+    \task Calculer $\complement{(\complement{A}\union B)} \union
+      \complement{(C\intersection D)}$.
+  \end{tasks}
+\end{exercise}
+\begin{solution}
+  \begin{tasks}(2)
+    \task $\set{5,6,7}$
+    \task $E$
+    \task $\set{3,4,5}$
+    \task $\set{1,2,3,4,6,7}$
+  \end{tasks}
+\end{solution}
+
+\end{document}
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-350028.pdf b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-350028.pdf
new file mode 100644
index 00000000000..ef781218a8e
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-350028.pdf
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-350028.tex b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-350028.tex
new file mode 100644
index 00000000000..ebe090413c9
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-350028.tex
@@ -0,0 +1,135 @@
+% http://tex.stackexchange.com/q/350028/
+\documentclass{book}
+
+\usepackage{xsimverb}
+\usepackage{xsim}
+\usepackage[most]{tcolorbox}
+\tcbuselibrary{skins,breakable}
+
+\DeclareExerciseEnvironmentTemplate{tcolorbox}
+  {%
+    \tcolorbox[
+      enhanced,
+      colframe=green!20!black,
+      colback=yellow!10!white,
+      coltitle=green!40!black,
+      fonttitle=\bfseries,
+      underlay={%
+        \begin{tcbclipinterior}
+          \shade[
+            inner color=\IfInsideSolutionTF{red!50!yellow}{green!80!yellow},
+            outer color=yellow!10!white]
+            (interior.north west) circle (2cm);
+          \draw[help lines,step=5mm,yellow!80!black,shift={(interior.north west)}]
+            (interior.south west) grid (interior.north east);
+          \end{tcbclipinterior}%
+        },
+      attach title to upper=\quad,
+      title = \XSIMmixedcase{\GetExerciseName}~\GetExerciseProperty{counter}
+      \IfExercisePropertySetT{points}{%
+        (\GetExerciseProperty{points}
+        \IfExerciseGoalSingularTF{points}
+          {\XSIMtranslate{point}}
+          {\XSIMtranslate{points}})%
+      }]%
+    \IfInsideSolutionT{\label{solution:\ExerciseID}}%
+  }
+  {%
+    \endtcolorbox
+    \vspace*{\baselineskip}
+    \IfInsideSolutionTF
+      {%
+        \noindent Exercise~\GetExerciseProperty{counter} is on
+        page~\GetExerciseProperty{page}.%
+      }
+      {%
+        \noindent The solution of this exercise is on
+        page~\pageref{solution:\ExerciseID}.%
+      }%
+    \vspace{\baselineskip}
+  }
+
+\xsimsetup{
+  exercise/template = tcolorbox ,
+  solution/template = tcolorbox
+}
+
+\usepackage{fmtcount,etoolbox}
+\newrobustcmd*\mystringnum[2]{\csname#1stringnum\endcsname{#2}}
+\renewcommand*\thechapter{\mystringnum{number}{\value{chapter}}}
+\renewcommand*\thesection{\arabic{chapter}.\arabic{section}}
+
+% for the header: \MakeUppercase{\mystringnum{number}{1}}
+%                 => \mystringnum{NUMBER}{1}
+%                 => \NUMBERstringnum{1}
+% elsewhere:      \mystringnum{number}{1}
+%                 => \numberstringnum{1}
+
+\usepackage{totcount}
+\regtotcounter{chapter}
+
+\newcounter{chapters}
+\setcounter{chapters}{1}
+\newcommand*\printsolutionsperchapter{%
+  \whileboolexpr
+    { test { \ifnumless {\value{chapters}} {\totvalue{chapter}+1} } }
+    {%
+      \printsolutions[chapter=\value{chapters},headings-template=per-chapter]
+      \stepcounter{chapters}%
+    }%
+}
+
+\begin{document}
+
+\chapter{The First Chapter}
+
+\begin{exercise}
+  Compute the derivative of the following function:
+  \begin{equation*}
+    f(x) = \sin((\sin x)^2)
+  \end{equation*}
+\end{exercise}
+\begin{solution}
+  The derivative is:
+  \begin{align*}
+    f’(x) &= ( \sin((\sin x)^2) )'
+           = \cos((\sin x)^2) \cdot 2\sin x \cos x
+  \end{align*}
+\end{solution}
+
+\begin{exercise}
+  Compute the derivative of the following function:
+  \begin{equation*}
+    f(x) = \sin((\sin x)^2)
+  \end{equation*}
+\end{exercise}
+\begin{solution}
+  The derivative is:
+  \begin{align*}
+    f’(x) &= ( \sin((\sin x)^2) )'
+           = \cos((\sin x)^2) \cdot 2\sin x \cos x
+  \end{align*}
+\end{solution}
+
+\chapter{The Second Chapter}
+
+\begin{exercise}
+  Compute the derivative of the following function:
+  \begin{equation*}
+    f(x) = (x^2+1) \sqrt{x^4+1}
+  \end{equation*}
+\end{exercise}
+\begin{solution}
+  The derivative is:
+  \begin{align*}
+    f’(x) &= ( (x^2+1) \sqrt{x^4+1} )'
+           = 2x\sqrt{x^4+1} + \frac{2x^3(x^2+1)}{\sqrt{x^4+1}}
+  \end{align*}
+\end{solution}
+
+\clearpage
+\section{Solutions of the Exercices}
+
+\printsolutionsperchapter
+
+\end{document}
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-369065.pdf b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-369065.pdf
new file mode 100644
index 00000000000..6aa9ab572bb
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-369065.pdf
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-369065.tex b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-369065.tex
new file mode 100644
index 00000000000..b62b85127a4
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-369065.tex
@@ -0,0 +1,77 @@
+% https://tex.stackexchange.com/q/369065/
+\documentclass{article}
+\usepackage{xsim,tcolorbox,needspace}
+
+\xsimsetup{
+  exercise/within=section ,
+  exercise/the-counter = \thesection.\arabic{exercise} ,
+  exercise/template=cyan-box ,
+  exercise/name=Example ,
+  solution/template=red ,
+  solution/print=true
+}
+
+\DeclareExerciseEnvironmentTemplate{cyan-box}
+  {%
+    \begin{tcolorbox}[arc=0mm,boxrule=1pt,colback=white,colframe=cyan,leftrule=3mm]
+      \textsf{%
+        \MakeUppercase{%
+          \XSIMmixedcase{\GetExerciseName}~\GetExerciseProperty{counter}%
+        }%
+      }%
+      \GetExercisePropertyT{subtitle}{ \textit{#1}}%
+      \quad
+  }
+  {\end{tcolorbox}}
+
+\DeclareExerciseEnvironmentTemplate{red}
+  {%
+    \par
+    \Needspace*{2\baselineskip}
+    \noindent
+    \textsf{\textcolor{red}{\MakeUppercase{\XSIMmixedcase{\GetExerciseName}}}}%
+    \quad
+  }
+  {\par\bigskip}
+
+\begin{document}
+
+\section{My first set of exercises}
+\begin{exercise}
+  Prove that $\frac{1}{2}\Delta(f_{ij}f^{ij})
+  =\nabla^{k}f^{ij}+f^{ij}f^{k}[2\nabla_{i}R_{jk}-\nabla_{k}R_{ij}]$
+\end{exercise}
+\begin{solution}
+  From \dots
+\end{solution}
+
+\begin{exercise}
+  Prove that Paulinho is smart.
+\end{exercise}
+\begin{solution}
+  All ducks are smart. Paulinho is a duck. Therefore, Paulinho is smart.
+\end{solution}
+
+\begin{exercise}
+  Prove that Paulinho is smart.
+\end{exercise}
+\begin{solution}
+  All ducks are smart. Paulinho is a duck. Therefore, Paulinho is smart.
+\end{solution}
+
+\section{My second set of exercises}
+\begin{exercise}
+  Prove that Paulinho is smart.
+\end{exercise}
+\begin{solution}
+  All ducks are smart. Paulinho is a duck. Therefore, Paulinho is smart.
+\end{solution}
+
+\begin{exercise}
+  Prove that Paulinho is smart.
+\end{exercise}
+\begin{solution}
+  All ducks are smart. Paulinho is a duck. Therefore, Paulinho is smart.
+\end{solution}
+
+\end{document}
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-369636.pdf b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-369636.pdf
new file mode 100644
index 00000000000..2bc106f3035
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-369636.pdf
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-369636.tex b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-369636.tex
new file mode 100644
index 00000000000..e13b8653f4c
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-369636.tex
@@ -0,0 +1,46 @@
+% https://tex.stackexchange.com/q/369686/
+\documentclass[a4paper,11pt]{article}
+\usepackage[top=2cm, bottom=3cm, left=4cm, right=4cm]{geometry}
+
+\usepackage[T1]{fontenc}
+\usepackage{fourier}
+\usepackage{tgpagella}
+\usepackage[utf8]{inputenc}
+
+\usepackage{xsim,needspace,adjustbox,scrextend}
+
+\xsimsetup{
+  exercise/the-counter = \arabic{exercise}. ,
+  exercise/template    = square
+}
+
+\DeclareExerciseEnvironmentTemplate{square}
+  {%
+    \Needspace*{2\baselineskip}%
+    \addmargin[0pt]{.15\textwidth}%
+    \par\noindent
+    \adjustbox{
+      fbox = 1pt 0pt,
+      lap = {\textwidth},
+      valign = t,
+      set vsize = {0pt}{0pt}
+    }{\rule{0pt}{20pt}\hspace{20pt}}%
+    \textbf{\GetExerciseProperty{counter}} %
+  }
+  {\endaddmargin\vspace{\baselineskip}}
+
+\usepackage{lipsum}
+
+\begin{document}
+
+\noindent\hrulefill
+
+\begin{exercise}
+  \lipsum[1]
+\end{exercise}
+
+\begin{exercise}
+  \lipsum[2]
+\end{exercise}
+
+\end{document}
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-369803.pdf b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-369803.pdf
new file mode 100644
index 00000000000..73eab39f10b
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-369803.pdf
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-369803.tex b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-369803.tex
new file mode 100644
index 00000000000..58b6800f937
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texsx-369803.tex
@@ -0,0 +1,50 @@
+% https://tex.stackexchange.com/q/369803
+\documentclass[a4paper,parskip=half]{scrartcl}
+\usepackage[utf8]{inputenc}
+\usepackage[ngerman]{babel}
+
+\usepackage{amsmath}
+\usepackage{amsthm} 
+\usepackage{amsfonts}
+\usepackage{amssymb}
+
+\usepackage[left=2cm,right=2.5cm,top=2.5cm,bottom=2cm]{geometry}
+
+\usepackage{xsim,siunitx}
+\DeclareExerciseTagging{difficulty}
+\DeclareExerciseEnvironmentTemplate{custom}
+  {%
+    \subsection*
+      {%
+        \XSIMmixedcase{\GetExerciseName}\nobreakspace
+        \GetExerciseProperty{counter}%
+        \IfInsideSolutionF
+          {%
+            \IfExercisePropertySetT{subtitle}
+              { {\normalfont(\GetExerciseProperty{subtitle})}}%
+          }%
+      }%
+  }{}
+
+\xsimsetup{
+  exercise/name = \XSIMtranslate{question} ,
+  exercise/template=custom ,
+  solution/print=true
+}
+
+\begin{document}
+
+\begin{exercise}[ID=wdsw, subtitle = Widerstandswürfel , difficulty = 2]
+  Gegeben ist ein Würfel, wobei jede der Kanten einen Widerstand von $R =
+  \SI{1}{\ohm}$ hat.
+  
+  Wie groß ist der Widerstand entlang einer Raumdiagonale?
+\end{exercise}
+\begin{solution}
+  Wir wollen den Widerstand zwischen den Punkten $X$ und $Y$ bestimmen, also
+  entlang der Raumdiagonale (siehe Abb. \ref{fig:wdsws1}). Weil die
+  Raumdiagonale eine Symmetrieachse ist, sollte das Problem symmetrisch sein,
+  und deswegen eine recht einfache Lösung haben.
+\end{solution}
+
+\end{document}
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.texwelt-15093.pdf b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texwelt-15093.pdf
new file mode 100644
index 00000000000..3dc9fb16494
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texwelt-15093.pdf
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.texwelt-15093.tex b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texwelt-15093.tex
new file mode 100644
index 00000000000..1f3fcfefcb7
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texwelt-15093.tex
@@ -0,0 +1,133 @@
+% http://texwelt.de/wissen/fragen/15093/
+\documentclass[paper=a4]{scrartcl}
+\usepackage[utf8]{inputenc}
+\usepackage[ngerman]{babel}
+
+\usepackage{xsim,needspace}
+
+\DeclareExerciseTagging{AFB}
+\DeclareExerciseEnvironmentTemplate{myexam}
+  {
+    \par\vspace{\baselineskip}
+    \Needspace*{3\baselineskip}
+    \noindent
+    \textbf{\IfInsideSolutionTF{Lösung}{Aufgabe}~\GetExerciseProperty{counter}.}%
+    \GetExercisePropertyT{subtitle}{\quad\textit{#1}}%
+    \hfill
+    \GetExercisePropertyT{AFB}{Schwierigkeit: #1}%
+    \GetExercisePropertyT{points}{%
+      \marginpar{%
+        \PropertyValue
+        \GetExercisePropertyT{bonus-points}{+\PropertyValue}%
+        \,P.%
+      }%
+    }%
+    \par\noindent
+  }
+  {}
+
+\xsimsetup{exercise/template=myexam}
+
+\begin{document}
+
+\begin{exercise}[subtitle=Eine Frage, AFB=1, points=3]
+  Das ist eine sehr tolle Frage.
+\end{exercise}
+
+\begin{exercise}[AFB=2, points=3]
+  Das ist eine sehr tolle Frage.
+\end{exercise}
+
+\begin{exercise}[AFB=3]
+  Das ist eine sehr tolle Frage.
+\end{exercise}
+
+\begin{exercise}[subtitle=Eine andere Frage, AFB=4, points=3]
+  Das ist eine sehr tolle Frage.
+\end{exercise}
+
+\begin{exercise}[subtitle=Eine Frage, AFB=2]
+  Das ist eine sehr tolle Frage.
+\end{exercise}
+
+\end{document}
+
+% andere Idee:
+\documentclass[paper=a4]{scrartcl}
+\usepackage[utf8]{inputenc}
+\usepackage[ngerman]{babel}
+
+\usepackage{xsim}
+
+\DeclareExerciseTagging{AFB}
+
+\DeclareExerciseEnvironmentTemplate{AFB}{%
+  \subsection*{%
+    \XSIMmixedcase{\GetExerciseName}\nobreakspace
+    \GetExerciseProperty{counter}%
+    \IfExercisePropertySetT{subtitle}%
+      { {\normalfont\itshape\GetExerciseProperty{subtitle}}}%
+  }
+  \marginpar{%
+    \GetExercisePropertyT{AFB}{%
+      \leavevmode\llap{Schwierigkeit: \PropertyValue\hspace*{\marginparsep}}%
+    }%
+    \GetExercisePropertyT{points}{%
+      \PropertyValue
+      \nobreakspace\XSIMtranslate{points}%
+    }%
+  }%
+}{}
+
+\DeclareExerciseEnvironmentTemplate{AFBsol}{%
+  \subsection*{%
+    \XSIMmixedcase{\GetExerciseName}\nobreakspace
+    \GetExerciseProperty{counter}%
+    \IfExercisePropertySetT{subtitle}%
+      { {\normalfont\itshape\GetExerciseProperty{subtitle}}}%
+  }
+  \textit{\small
+    \GetExercisePropertyT{AFB}{Schwierigkeit: \PropertyValue}%
+    \GetExercisePropertyT{points}{%
+      \IfExercisePropertySetT{AFB}{ }%
+      (\PropertyValue\nobreakspace\XSIMtranslate{points})%
+    }%
+  }%
+  \par\noindent
+}{}
+
+\DeclareExerciseTranslation{German}{default-heading}{Lösungen}
+
+\xsimsetup{
+  exercise/template=AFB ,
+  solution/template=AFBsol ,
+  exercise/name=Aufgabe
+}
+
+\begin{document}
+
+\begin{exercise}[subtitle=Eine Frage, AFB=1, points=3]
+  Das ist eine sehr tolle Frage.
+\end{exercise}
+\begin{solution}
+  Das ist eine tolle Lösung!
+\end{solution}
+\begin{exercise}[AFB=2, points=3]
+  Das ist eine sehr tolle Frage.
+\end{exercise}
+
+\begin{exercise}[AFB=3]
+  Das ist eine sehr tolle Frage.
+\end{exercise}
+
+\begin{exercise}[subtitle=Eine andere Frage, AFB=4, points=3]
+  Das ist eine sehr tolle Frage.
+\end{exercise}
+
+\begin{exercise}[subtitle=Eine Frage, AFB=2]
+  Das ist eine sehr tolle Frage.
+\end{exercise}
+
+\printsolutions
+
+\end{document}
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.texwelt-6698.pdf b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texwelt-6698.pdf
new file mode 100644
index 00000000000..000663bf445
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texwelt-6698.pdf
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.texwelt-6698.tex b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texwelt-6698.tex
new file mode 100644
index 00000000000..9e388b9f690
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.texwelt-6698.tex
@@ -0,0 +1,86 @@
+% http://texwelt.de/wissen/fragen/6698/
+\documentclass{article}
+\usepackage[utf8]{inputenc}
+\usepackage[ngerman]{babel}
+
+\usepackage{needspace}
+\usepackage{xsim}
+\xsimsetup{
+  exercise/name = Aufgabe ,
+  solution/name = Lösung ,
+  exercise/within = section ,
+  exercise/the-counter = \thesection.\arabic{exercise} ,
+  exercise/template = mine
+}
+
+\newif\iflist
+
+\DeclareExerciseEnvironmentTemplate{mine}{
+  \par\vspace{\baselineskip}
+  \Needspace*{3\baselineskip}
+  \noindent
+  \textbf{\GetExerciseName~\GetExerciseProperty{counter}}%
+  \GetExercisePropertyT{subtitle}{\quad\textit{#1}}%
+  \iflist
+    \GetExercisePropertyT{page}{ (Seite~#1)}%
+  \fi
+  % not necessary if you don't use points:
+  \GetExercisePropertyT{points}{%
+    \marginpar{%
+      \PropertyValue
+      \GetExercisePropertyT{bonus-points}{+\PropertyValue}%
+      \,\XSIMtranslate{points-abbr}%
+    }%
+  }%
+  \par\noindent
+}
+{}
+
+\usepackage{multicol}
+
+\begin{document}
+
+\section{Erstes Kapitel}
+\begin{exercise}
+  Eine erste Aufgabe
+\end{exercise}
+\begin{exercise}
+  Eine zweite Aufgabe
+\end{exercise}
+
+\subsection{Erstes Unterkapitel}
+\begin{exercise}
+  Eine Aufgabe in einem Unterkapitel
+\end{exercise}
+\begin{exercise}
+  Noch eine Aufgabe in einem Unterkapitel
+\end{exercise}
+
+\subsubsection{Tiefer geschachteltes Unterkapitel}
+\begin{exercise}
+  Noch eine Aufgabe
+\end{exercise}
+
+\subsubsection{Weiter geschachtelt}
+\begin{exercise}
+  Eine weitere Aufgabe
+\end{exercise}
+
+\subsection{Zweites Unterkapitel}
+\begin{exercise}
+  Und eine weitere Aufgabe
+\end{exercise}
+
+\clearpage
+
+\section{Zweites Kapitel}
+\begin{exercise}
+  Eine Aufgabe in einem anderen Kapitel
+\end{exercise}
+
+\begin{multicols}{2}[\section{Aufgabenübersicht}]
+  \listtrue
+  \printcollection{all exercises}
+\end{multicols}
+
+\end{document}
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.various.pdf b/Master/texmf-dist/doc/latex/xsim/examples/xsim.various.pdf
new file mode 100644
index 00000000000..b8f033c7599
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.various.pdf
diff --git a/Master/texmf-dist/doc/latex/xsim/examples/xsim.various.tex b/Master/texmf-dist/doc/latex/xsim/examples/xsim.various.tex
new file mode 100644
index 00000000000..1b7b13f98b3
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/examples/xsim.various.tex
@@ -0,0 +1,237 @@
+\documentclass{article}
+\usepackage{xsim,lipsum,tcolorbox}
+
+\DeclareExerciseType{question}{
+  exercise-env = question ,
+  solution-env = hint ,
+  exercise-name = Question ,
+  solution-name = Hint ,
+  exercise-template = default ,
+  solution-template = default ,
+  counter = exercise % shares a counter with the `exercise' type
+}
+
+\DeclareExerciseType{problem}{
+  exercise-env = problem ,
+  solution-env = answer ,
+  exercise-name = Problem ,
+  solution-name = Answer ,
+  exercise-template = tcolorbox ,
+  solution-template = tcolorbox
+}
+
+\DeclareExerciseProperty{grade}
+\DeclareExerciseProperty{difficulty}
+
+\tcbuselibrary{breakable}
+\DeclareExerciseEnvironmentTemplate{tcolorbox}
+  {%
+    \newcommand*\writehere{%
+      \IfInsideSolutionTF{}{%
+        \tcblower
+        \emph{Your answer:}
+        \vspace*{4cm}
+      }%
+    }
+    \vspace{\baselineskip}
+    \tcolorbox[
+      colback = red!5!white ,
+      colframe = red!75!black ,
+      colbacktitle = yellow!50!red ,
+      coltitle = red!25!black ,
+      fonttitle = \bfseries ,
+      subtitle style = {
+        boxrule = 0.4pt ,
+        colback = yellow!50!red!25!white
+      } ,
+      breakable ,
+      title = \GetExerciseName~\GetExerciseProperty{counter}
+      \IfExercisePropertySetT{points}{%
+        (\GetExerciseProperty{points}
+        \IfExerciseGoalSingularTF{points}
+          {\XSIMtranslate{point}}
+          {\XSIMtranslate{points}})%
+      }]
+    \IfInsideSolutionF{%
+      \IfExercisePropertySetT{tags}{%
+        Tags: \ListExerciseTags{tags}{, } \par
+      }%
+    }%
+  }
+  {%
+    \endtcolorbox
+    \vspace{\baselineskip}
+  }
+
+\xsimsetup{
+  % tags = {geometry} ,
+  % topics = {geometry}
+  % tags/ingore-untagged % if true untagged exercise will be printed regardless
+  %                      % which tags have been chosen
+}
+
+\begin{document}
+
+\gradingtable \par \bigskip
+
+Total: \printtotalpoints \par
+from questions: \printpoints{question} \par
+from exercises: \printpoints{exercise} \par
+from problems: \printpoints{problem} \par \bigskip
+
+Total bonus: \printtotalbonus \par
+from questions: \printbonus{question} \par
+from exercises: \printbonus{exercise} \par
+from problems: \printbonus{problem} \par
+
+% 1
+\begin{exercise}[points=4,bonus-points=1,topics=geometry,tags={geometry,triangles},grade=7]
+  \lipsum[1]
+\begin{verbatim}
+foo x^2 y^3 \gna
+\end{verbatim}
+\end{exercise}
+\begin{solution}[print]
+  This is the solution to \ExerciseType\ \GetExerciseProperty{counter}.
+\begin{verbatim}
+foo x^2 y^3 \gna
+\end{verbatim}
+\end{solution}
+
+% 2
+\begin{exercise}[subtitle=Foo,points=5,topics=analysis,tags={analysis,functions},grade=11]
+  \lipsum[2]
+\end{exercise}
+\begin{solution}
+  This is the solution to \ExerciseType\ \GetExerciseProperty{counter}.
+\end{solution}
+
+% 3
+\begin{problem}[tags={analysis,functions}]
+  \lipsum[3]
+  \writehere
+\end{problem}
+\begin{answer}
+  This is the solution to \ExerciseType\ \GetExerciseProperty{counter}.
+\end{answer}
+
+% 4
+\begin{question}
+  \lipsum[4]
+  
+  \verb+\ExerciseID+: \GetExerciseAliasProperty{ID}
+  
+  \verb+\GetExerciseProperty{id}+: \GetExerciseProperty{id}
+  
+  \verb+\GetExerciseAliasProperty{ID}+: \GetExerciseAliasProperty{ID}
+  
+  \verb+\GetExerciseProperty{ID}+: \GetExerciseProperty{ID}
+\end{question}
+\begin{hint}
+  This is the solution to \ExerciseType\ \GetExerciseProperty{counter}.
+\end{hint}
+
+% 5
+\begin{problem}[points=2]
+  \lipsum[3]
+  
+  \verb+\ExerciseID+: \GetExerciseAliasProperty{ID}
+  
+  \verb+\GetExerciseProperty{id}+: \GetExerciseProperty{id}
+  
+  \verb+\GetExerciseAliasProperty{ID}+: \GetExerciseAliasProperty{ID}
+  
+  \verb+\GetExerciseProperty{ID}+: \GetExerciseProperty{ID}
+  \writehere
+\end{problem}
+\begin{answer}
+  This is the solution to \ExerciseType\ \GetExerciseProperty{counter}.
+\end{answer}
+
+% 6
+\begin{problem}[points=1]
+  \lipsum[3]
+
+  \verb+\ExerciseID+: \GetExerciseAliasProperty{ID}
+  
+  \verb+\GetExerciseProperty{id}+: \GetExerciseProperty{id}
+  
+  \verb+\GetExerciseAliasProperty{ID}+: \GetExerciseAliasProperty{ID}
+  
+  \verb+\GetExerciseProperty{ID}+: \GetExerciseProperty{ID}
+\end{problem}
+\begin{answer}
+  This is the solution to \ExerciseType\ \GetExerciseProperty{counter}.
+\end{answer}
+
+% 7
+\begin{exercise}[ID=test]
+  \lipsum[5]
+
+  \verb+\ExerciseID+: \GetExerciseAliasProperty{ID}
+  
+  \verb+\GetExerciseProperty{id}+: \GetExerciseProperty{id}
+  
+  \verb+\GetExerciseAliasProperty{ID}+: \GetExerciseAliasProperty{ID}
+  
+  \verb+\GetExerciseProperty{ID}+: \GetExerciseProperty{ID}
+\end{exercise}
+\begin{solution}
+  This is the solution to \ExerciseType\ \GetExerciseProperty{counter}.
+\end{solution}
+
+% 8
+\begin{exercise}[print=false,use=false]
+  \lipsum[5]
+\end{exercise}
+\begin{solution}
+  This is the solution to \ExerciseType\ \GetExerciseProperty{counter}.
+\end{solution}
+
+% \printsolutionstype{exercise}
+
+\printsolutions*
+
+\section{Statistics}
+
+\ForEachUsedExerciseByType{%
+  \noindent\XSIMmixedcase{\ExerciseParameterGet{#1}{exercise-name}}~#3: \\
+  \hspace*{2em}id: #2, type: #1, subtitle: #4, points: #5, bonus: #6\par \medskip
+}
+
+\bigskip
+
+\ForEachUsedExerciseByID{%
+  \noindent\XSIMmixedcase{\ExerciseParameterGet{#1}{exercise-name}}~#3: \\
+  \hspace*{2em}id: #2, type: #1, subtitle: #4, points: #5, bonus: #6\par \medskip
+}
+
+\bigskip
+
+\ForEachUsedExerciseByType{%
+  \ExercisePropertyIfSetT{#1}{#2}{points}
+    { \XSIMmixedcase{\ExerciseParameterGet{#1}{exercise-name}}~#3: #5~points\par }%
+}
+
+\bigskip
+
+Number of questions: \numberofquestions \par
+Number of exercises: \numberofexercises \par
+Number of problems: \numberofproblems
+
+\section{Grading tables}
+
+\gradingtable[template=default*,type=exercise] \par \bigskip
+
+\gradingtable[template=default*,type=problem] \par \bigskip
+
+\gradingtable[template=default*] \par \bigskip
+
+% vertical
+\gradingtable[type=exercise] \par \bigskip
+
+\gradingtable[type=problem] \par \bigskip
+
+\gradingtable
+
+\end{document}
diff --git a/Master/texmf-dist/doc/latex/xsim/xsim.history b/Master/texmf-dist/doc/latex/xsim/xsim.history
new file mode 100644
index 00000000000..895e7a47a3b
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/xsim.history
@@ -0,0 +1,81 @@
+--------------------------------------------------------------------------
+
+XSIM -- eXercise Sheets IMproved
+
+--------------------------------------------------------------------------
+Clemens Niederberger
+Web:    https://github.com/cgnieder/xsim
+E-Mail: contact@mychemistry.eu
+--------------------------------------------------------------------------
+Copyright 2017 Clemens Niederberger
+
+This work may be distributed and/or modified under the
+conditions of the LaTeX Project Public License, either version 1.3
+of this license or (at your option) any later version.
+The latest version of this license is in
+  http://www.latex-project.org/lppl.txt
+and version 1.3 or later is part of all distributions of LaTeX
+version 2005/12/01 or later.
+
+This work has the LPPL maintenance status `maintained'.
+
+The Current Maintainer of this work is Clemens Niederberger.
+--------------------------------------------------------------------------
+
+HISTORY:
+
+ v0.0   2017/02/09 - start with coding the first ideas
+ v0.1   2017/03/19 - first draft which actually seems to do everything as
+                     planned
+ v0.2   2017/03/21 - bugfix in the verbwrite module
+                   - add `use!' and `print!' properties
+                   - add the concepts of `noupdate' and `boolean' properties
+ v0.4   2017/03/24 - \IfExerciseBooleanPropertyTF
+                   - \GetExercisePropertyTF, \PropertyValue
+                   - \printallsolutions
+                   - \UseExerciseTemplate
+                   - bug fix in solution environments: now get printed again
+                     when option `print=true' is used
+                   - bug fix to the translations of the solution list headings:
+                     exercise name instead of exercise type is now printed
+                   - \AddtoExerciseTypeGoal, \AddtoExerciseGoal
+                     \AddtoExerciseTypeGoalPrint, \AddtoExerciseGoalPrint,
+                     \ExerciseGoalValuePrint
+                   - \addpoints, \addbonus, \points, \printgoal
+ v0.5   2017/03/30 - add style file mechanism
+                   - make solution print conditions `section' and `chapter'
+                     combinable
+ v0.5a  2017/04/15 - fix wrong translation of the `default-heading'
+ v0.5b  2017/04/16 - add \SetExerciseProperty
+ v0.6   2017/04/27 - official interface for grade distributions
+                   - refine hook management (environment module)
+ v0.6a  2017/04/28 - refine \blank command, add documentation for said command
+ v0.7   2017/05/09 - \xsim_list_length:n
+                   - new boolean property `used'
+                   - when an exercise is collected the counter isn't stepped
+                     but only when the exercise is inserted for the first
+                     time; when this happens the new property `used' is set to
+                     `true' 
+                   - make setting boolean properties case insensitive
+                   - add missing pieces to manual (eg `page' property...)
+                   - \TotalExerciseGoals and \TotalExerciseTypeGoals
+                   - \XSIMifchapterTF
+                   - \xsim_if_goal_sum:nnnTF and friends,
+                     \IfExerciseTypeGoalsSumTF and \IfExerciseGoalsSumTF
+                   - some more hints in the manual regarding collections
+ v0.8   2017/05/18 - bug fix in \xsim_set_property:nnnn
+                   - random exercise lists from collections
+                   - \xsim_collection_count:n
+                   - \GetExerciseIdForProperty and \GetExerciseTypeForProperty
+                     for unique properties
+                   - set property `print=false' during collection and only to
+                     true when the corresponding exercises actually are
+                     printed
+                   - do not insert \par at the beginning and end of exercises
+                     and solutions; this should be left to the templates!
+                   - new option `print-collection/print' which allows to
+                     choose between exercises, solutions, and both to be
+                     printed
+                   - new parameter `solution-counter' in order to avoid
+                     possible conflicts with existing counters
+ v0.8a  2017/05/19 - \IfPrintSolutionTF
diff --git a/Master/texmf-dist/doc/latex/xsim/xsim.ideas b/Master/texmf-dist/doc/latex/xsim/xsim.ideas
new file mode 100644
index 00000000000..bb43c7fec07
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/xsim.ideas
@@ -0,0 +1,31 @@
+--------------------------------------------------------------------------
+
+XSIM -- eXercise Sheets IMproved
+
+--------------------------------------------------------------------------
+Clemens Niederberger
+Web:    https://github.com/cgnieder/xsim
+E-Mail: contact@mychemistry.eu
+--------------------------------------------------------------------------
+Copyright 2017 Clemens Niederberger
+
+This work may be distributed and/or modified under the
+conditions of the LaTeX Project Public License, either version 1.3
+of this license or (at your option) any later version.
+The latest version of this license is in
+  http://www.latex-project.org/lppl.txt
+and version 1.3 or later is part of all distributions of LaTeX
+version 2005/12/01 or later.
+
+This work has the LPPL maintenance status `maintained'.
+
+The Current Maintainer of this work is Clemens Niederberger.
+--------------------------------------------------------------------------
+
+IDEAS:
+
+- a document class `xsim-exam' for creating exams
+- a mechanism for providing variants of an exam
+- provide a switch: either write the environments to an external file
+  or save it to an auxiliary file ? (not really sure about this one --
+  probably not)
diff --git a/Master/texmf-dist/doc/latex/xsim/xsim_manual.pdf b/Master/texmf-dist/doc/latex/xsim/xsim_manual.pdf
new file mode 100644
index 00000000000..3a0fa539656
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/xsim_manual.pdf
diff --git a/Master/texmf-dist/doc/latex/xsim/xsim_manual.tex b/Master/texmf-dist/doc/latex/xsim/xsim_manual.tex
new file mode 100644
index 00000000000..2e351c7a64e
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/xsim/xsim_manual.tex
@@ -0,0 +1,2188 @@
+% !arara: pdflatex: { action: nonstopmode }
+% !arara: biber
+% arara: pdflatex: { action: nonstopmode }
+% arara: pdflatex: { action: nonstopmode }
+% arara: pdflatex: { action: nonstopmode }
+% ----------------------------------------------------------------------------
+% the XSIM package
+% 
+%   eXercise Sheets IMproved
+% 
+% ----------------------------------------------------------------------------
+% Clemens Niederberger
+% Web:    https://github.com/cgnieder/xsim
+% E-Mail: contact@mychemistry.eu
+% ----------------------------------------------------------------------------
+% Copyright 2017 Clemens Niederberger
+% 
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+% 
+% This work has the LPPL maintenance status `maintained'.
+% 
+% The Current Maintainer of this work is Clemens Niederberger.
+% ----------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% ----------------------------------------------------------------------------
+\documentclass{xsim-manual}
+
+\usepackage{filecontents}
+\begin{filecontents*}{\jobname.bib}
+@online{texsx:romannumeral,
+  author = {Bruno Le Floch} ,
+  title = {Cunning (La)TeX tricks} ,
+  urldate = {2017-03-02} ,
+  url = {http://tex.stackexchange.com/a/19769/}
+}
+@online{texsx:tagged/exsheets,
+  title = {Questions tagged `exsheets'} ,
+  author = {various} ,
+  url = {http://tex.stackexchange.com/questions/tagged/exsheets} ,
+  urldate = {2017-05-15}
+}
+\end{filecontents*}
+\addbibresource{\jobname.bib}
+
+\begin{document}
+
+\section{Licence, Requirements and \textsc{readme}}
+\license
+
+\xsim\ loads the packages \pkg{expl3}~\cite{bnd:l3kernel},
+\pkg{xparse}~\cite{bnd:l3packages}, \pkg{etoolbox}~\cite{pkg:etoolbox},
+\pkg{array}~\cite{pkg:array} \pkg{booktabs}~\cite{pkg:booktabs} and
+\pkg{translations}~\cite{pkg:translations}.  All of these packages are present
+on a modern and up to date \TeX\ distribution such as \TeX~Live or MiK\TeX\ so
+no further action should be needed.  When you are using \xsim\ you should be
+using an up to date \TeX\ distribution, anyway.
+
+\begin{bewareofthedog}
+  Newer versions of \xsim\ may depend on newer versions of the support
+  packages.  Remember: it is always dangerous to update single packages.
+  Always update your \TeX\ distribution if you want an up to date version of a
+  package.  Be careful: if you're in the middle of an important project it
+  might be better to wait with the update until you've finished the project.
+  Every update might be breaking some things.
+\end{bewareofthedog}
+
+\section{Motivation and Background}
+
+It has been quite a while since I first published
+\pkg{exsheets}~\cite{pkg:exsheets} in June 2012.  Since then it has gained a
+user base and a little bit of popularity as the number of questions on tex.sx
+shows (103~at the time of writing)~\cite{texsx:tagged/exsheets}.  User
+questions, bug reports and feature requests improved it over the time.  It
+still has a version number starting with a zero, though, which in my
+versioning system means I still consider it experimental.
+
+This is due to several facts.  It lacks a few features which I consider
+essential for a full version~1.  For one thing it is not possible to have
+several kinds of exercises numbered independently.  Using verbatim material
+such as listings inside exercises and solutions is not possible and the
+current workaround isn't that ideal either.  One request which dates back
+quite a while now was to have different types of points to exercises\ldots
+
+All of those aren't easy to add due to the way \pkg{exsheets} is implemented
+right now. As a consequence I wanted to re-implement \pkg{exsheets} for a long
+time.  This is what lead to \xsim.  Internally the package works completely
+different.
+
+\begin{bewareofthedog}
+  \xsim\ will be the official successor of \pkg{exsheets} which is now
+  considered obsolete but will stay alive and will still receive bugfix
+  releases. However, new features will not be added to \pkg{exsheets} any
+  more.
+\end{bewareofthedog}
+
+\section{How to Read the Manual}\label{sec:how-read-manual}
+
+\subsection{Nomenclature}
+
+Throughout this manual certain terms are used.  This section explains their
+meaning in this manual.
+
+\acuseall
+\printacronyms[heading=none]
+
+\subsection{Package Options}\label{sec:package-options}
+\xsim\ has these package options:
+\begin{options}
+  \opt{verbose}
+    Writes extensive information about what \xsim\ is doing into the log
+    file.
+  \opt{final}
+    If used the exercise and solution environments will not rewrite the
+    environment body files.
+  \opt{clear-aux}
+    If used every time the  total number of exercise changes \xsim\ will write
+    \emph{less} information to the auxfile on the next run and only if the
+    number of exercises stays stable between compilations the needed
+    information will be written to the auxfile. \emph{This needs more
+      compilations until everything stabilizes but should reduce the
+      probability of possibly faulty exercises after changes to the document.}
+    The \option{final} option automatically disables this option.  See also
+    sections~\vref{sec:how-exerc-envir} and~\vref{sec:resolve-getting}.
+\end{options}
+
+Those options are used the usual way as package option
+\begin{sourcecode}
+  \usepackage[verbose]{xsim}
+\end{sourcecode}
+or as global option
+\begin{sourcecode}
+  \documentclass[verbose]{article}
+\end{sourcecode}
+or via the setup command:
+\begin{commands}
+  \command{xsimsetup}[\marg{options}]
+    Set up \xsim's package options and all other options described at
+    other places in the manual.
+\end{commands}
+
+\subsection{Setting Options}
+Apart from the package options already described in
+section~\vref{sec:package-options} \xsim\ has further options. Those can be
+\enquote{toplevel} options or options belonging to a module.
+\begin{options}
+  \keyval*{toplevel}{value}
+    A toplevel option.
+  \keyval*{sublevel}{value}\Module*{module}
+    A sublevel option belonging to the module \module*{module}
+\end{options}
+Both kinds of options are set with \cs{xsimsetup}:
+\begin{sourcecode}
+  \xsimsetup{
+    toplevel = {value} ,
+    module/sublevel = {value}
+  }
+\end{sourcecode}
+
+\subsection{Command descriptions}
+
+Some commands do have a \expandablesymbol\ symbol printed next to their
+names.  This indicates that the command is expandable, \ie, it is usable in an
+\cs*{edef} or \cs*{write} context and will expand according to its
+description.  All other commands are engine protected, \ie, in the sense of
+\eTeX's \cs*{protected}.
+
+Some command name descriptions end with \code{\TF}.
+\begin{commands}
+  \command*{SomeCommand\TF}[\meta{arguments}\marg{true}\marg{false}]
+    A command with maybe some arguments and ending with the two arguments
+    \meta{true} and \meta{false}.
+\end{commands}
+This means two things: the command is a conditional which tests something and
+depending on the outcome of the test leaves either the \meta{true} argument
+(\code{T}) or the \meta{false} argument (\code{F}) in the input stream.  It
+also means two additional commands exist:
+\begin{commands}
+  \command*{SomeCommandT}[\meta{arguments}\marg{true}]
+    The same as \cs*{SomeCommandTF} but only with the \meta{true} argument and
+    no \meta{false} argument.
+  \command*{SomeCommandF}[\meta{arguments}\marg{false}]
+    The same as \cs*{SomeCommandTF} but only with the \meta{false} argument and
+    no \meta{true} argument.
+\end{commands}
+
+
+\section{Exercises and Solutions}
+
+The two predefined environments for exercises and solutions are the following
+ones:
+\begin{environments}
+  \environment{exercise}[\oarg{\acsp*{prop}}]
+    Input and typeset an exercise.  See section~\vref{sec:exercise-properties}
+    for details on exercise \acsp*{prop}.
+  \environment{solution}[\oarg{options}]
+    Input and typeset the solution to the exercise of the previous
+    \env{exercise} environment.  See section~\vref{sec:printing-solutions} for
+    details on options of solutions.
+\end{environments}
+
+\begin{example}
+  \begin{exercise}
+    A first example for an exercise.
+  \end{exercise}
+  \begin{solution}
+    A first example for a solution.
+  \end{solution}
+\end{example}
+
+As can be seen in the example a solution is not printed with the default
+setup.  This can be changed using the following option.
+\begin{options}
+  \keybool{print}\Module{solution}\Default{false}
+    Set if solutions are printed or or not.
+\end{options}
+
+The option (belonging to the module \module*{solution}) can either be set
+locally as option to the \env{solution} environment
+\begin{sourcecode}
+  \begin{solution}[print=true]
+    A first example for a solution.
+  \end{solution}
+\end{sourcecode}
+or with the setup command for all following solutions:
+\begin{sourcecode}
+  \xsimsetup{
+    solution/print = true
+  }
+\end{sourcecode}
+
+There is an completely analoguous option for the \env{exercise} environment:
+\begin{options}
+  \keybool{print}\Module{exercise}\Default{true}
+    Set if exercises are printed or or not.
+\end{options}
+More details on those two environments can be found in
+section~\vref{sec:using-printing}.
+
+\section{How the Exercise Environments Work}\label{sec:how-exerc-envir}
+Both enviroments write the contents of their bodies verbatim to external files
+following a certain naming structure:
+\begin{itemize}
+  \item
+  \code{\meta{jobname}-\meta{type}-\meta{id}-exercise|solution-body.tex} 
+\end{itemize}
+The name starts with the name of the job (which is the name of the document
+itself) followed by type and id of the corresponding exercise and then
+followed by the environment type.  For example both enviroments from the first
+example have been written to files named
+\begin{itemize}
+  \item \verbcode+xsim_manual-exercise-1-exercise-body.tex+ and
+  \item \verbcode+xsim_manual-exercise-1-solution-body.tex+, respectively.
+\end{itemize}
+Details on the \meta{type} of an exercise will be given in
+section~\vref{sec:new-exercise-types}.  \emph{The \meta{id} of an exercise is
+  a positive integer unique to each exercise environment regardless if the
+  exercise is being printed or used at all.}
+
+These external files are input when the respective exercise or solution is
+printed.  An advantage of using external files is that \emph{verbatim material
+  is allowed} inside the environments.  Each of those files contains some
+information about itself and where and why it was generated\footnote{In this
+  example the sourcecode line number is misleading as the example where the
+  file was generated itself was an external file where the \env{exercise}
+  environment indeed \emph{was} on line~1.}:
+
+\inputsourcecode{exercises/xsim_manual-exercise-1-exercise-body.tex}
+
+Arguably one downside of the approach using external files for each exercise
+and its solution is that your project folder will be cluttered with files.  In
+order to deal with this somehow \xsim\ offers the following option:
+\begin{options}
+  \keyval{path}{path name}\Default
+    With this option a subfolder or path within the main project folder can be
+    given.  Exercises will be written to and included from this path.
+    \emph{The path must exist on your system before you can use it!} This
+    document uses \keyis{path}{exercises}.
+\end{options}
+
+\begin{bewareofthedog}
+  \xsim\ writes a lot of stuff to the auxfile for re-using information on
+  subsequent compilations.  If you add exercises, change properties \etc\ it
+  might happen that wrong information is staying in the auxfile and is wrongly
+  used by \xsim.  In such cases deleting the auxfile and doing a few fresh
+  compilations may resolve your problems.
+
+  Sometimes the \emph{existence of exercise or solution files from earlier
+    compilations} may lead to wrong lists of exercises or solutions.  In such
+  cases it can be useful to delete all those files and doing a fresh
+  compilation.  It may be helpful to use a subfolder for those exernal files
+  which will make deleting them a little bit easier. (Don't forget to both
+  create the subfolder and set \option{path} accordingly then.)
+
+  Using the \option{clear-aux} option might help to reduce erroneous exercises.
+\end{bewareofthedog}
+
+\section{New Exercise Types}\label{sec:new-exercise-types}
+
+It is easy to define new exercise environments together with a corresponding
+solution environment using the following command:
+\begin{commands}
+  \command{DeclareExerciseType}[\marg{type}\marg{parameters}]
+    Declare a new exercise type analoguous to the \env{exercise} and
+    \env{solution} environments.
+\end{commands}
+Declaring a new exercise type will also define a new command:
+\begin{commands}
+  \command{numberof\meta{exercise-env}s}
+    These commands hold the absolut number of used exercises of type
+    \meta{type}.  The meaning of \meta{exercise-env} will become clear below
+    when the exercise parameters are explained.  It is always the same as the
+    exercise environment name.
+\end{commands}
+\begin{example}
+  There are \numberofexercises~exercises and \numberofproblems~problem in this
+  manual.
+\end{example}
+\xsim's pre-defined environment pair has been defined as follows:
+\begin{sourcecode}
+  \DeclareExerciseType{exercise}{
+    exercise-env      = exercise ,
+    solution-env      = solution ,
+    exercise-name     = \XSIMtranslate{exercise} ,
+    solution-name     = \XSIMtranslate{solution} ,
+    exercise-template = default ,
+    solution-template = default
+  }
+\end{sourcecode}
+
+The above already is an example for almost all parameters that can (and often
+must) be set.  Here is the complete list:
+\begin{parameters}
+  \paraval{exercise-env}{exercise environment name}
+    The name for the environment used for the exercises of type \meta{type}.
+    \emph{This parameter is mandatory.} It can't be changed afterwards.
+  \paraval{solution-env}{solution environment name}
+    The name for the environment used for the solutions of type \meta{type}.
+    \emph{This parameter is mandatory.} It can't be changed afterwards.
+  \paraval{exercise-name}{exercise name}
+    The name of the exercises of type \meta{type} -- used for typesetting.
+    \emph{This parameter is mandatory.}
+  \paraval{solution-name}{solution name}
+    The name of the solutions of type \meta{type} -- used for typesetting.
+    \emph{This parameter is mandatory.}
+  \paraval{exercise-template}{exercise template}
+    The template used for typesetting the exercises of type \meta{type}.
+    \emph{This parameter is mandatory.} See
+    section~\vref{sec:styl-exerc-templ} for details on templates.
+  \paraval{solution-template}{solution template}
+    The template used for typesetting the exercises of type \meta{type}.
+    \emph{This parameter is mandatory.} See
+    section~\vref{sec:styl-exerc-templ} for details on templates.
+  \paraval{counter}{counter name}
+    The counter used for the exercises of type \meta{type}.  If not explicitly
+    set the counter with the same name as \parameter{exercise-env} is used.
+    Otherwise the specified counter is used.  This enables to have different
+    types of exercises sharing a common counter.  \emph{This parameter can't
+      be changed afterwards.}  If the explicit or implicit counter does not
+    exist, yet, it will be defined.
+  \paraval{solution-counter}{counter name}
+    The counter used for the solutions of type \meta{type}.  If not explicitly
+    set the counter with the same name as \parameter{solution-env} is used.
+    Otherwise the specified counter is used.  This enables to have different
+    types of solutions sharing a common counter although this doesn't actually
+    make much sense.  But it can be useful to avoid using an already existing
+    counter. \emph{This parameter can't be changed afterwards.}  If the
+    explicit or implicit counter does not exist, yet, it will be defined.  The
+    sole purpose of this counter is to be able to label solutions so they can
+    be \cs*{pageref}ed.
+  \paraval{number}{integer}
+    An internal parameter that is used to keep track of the number of
+    exercises of a type.  This parameter cannot be set or changed by the
+    user.
+\end{parameters}
+
+It is possible to change some of the parameters after an exercise type has
+been defined.  Those include \parameter{exercise-name},
+\parameter{solution-name}, \parameter{exercise-template}, and
+\parameter{solution-template}:
+\begin{commands}
+  \command{SetExerciseParameter}[\marg{type}\marg{parameter}\marg{value}]
+    Usable to set a single parameter to a new value.
+  \command{SetExerciseParameters}[\marg{type}\marg{parameters}]
+    Set several parameters at once. \meta{parameters} is a csv list of
+    key/value pairs.
+\end{commands}
+If you try to set an already set but fixed parameter like
+\parameter{exercise-env} a warning will be written to the log file.  For all
+parameters that can be changed also options exist wich can be set via
+\cs{xsimsetup}.  They are explained in
+section~\vref{sec:environment-options-hooks}.
+
+\begin{bewareofthedog}
+  All exercises of a type use the parameters
+  (\eg, \parameter{exercise-template}) that are \emph{currently active}.  If
+  you want exercises with a different look or different names in the same
+  document you should use different exercises types.
+\end{bewareofthedog}
+
+\section{Exercise Properties}\label{sec:exercise-properties}
+
+\subsection{Predefined Properties}
+
+Exercise like the \env{exercise} environment and possibly others defined with
+\cs{DeclareExerciseType} have a number of predefined \acsp*{prop}:
+\begin{properties}
+  \propval{id}{integer}
+    Holds the internal id of an exercise.  \emph{Cannot be set by the user}.
+  \propval{ID}{text}
+    Holds the user id of an exercise if defined.  Otherwise it is equal to
+    \property{id}.
+  \propval{counter}{text}
+    Holds the counter value represenation of an exercise (\ie, what you
+    usually know as \cs*{the\meta{counter}}).  \emph{Cannot be set by the
+      user}.
+  \propval{counter-value}{integer}
+    Holds the counter value of an exercise (\ie, what you usually know as
+    \cs*{arabic}\marg{counter}).  \emph{Cannot be set by the user}.
+  \propval{subtitle}{text}
+    Holds the subtitle of an exercise.
+  \propval{points}{number}
+    Holds the reachable points of an exercise.
+  \propval{bonus-points}{number}
+    Holds the reachable bonus-points of an exercise.
+  \propbool{print}
+    Holds the print boolean of an exercise.
+  \propbool{print\bang}
+    Holds a special print boolean of an exercise, see
+    page~\pageref{property:print!}.
+  \propbool{use}
+    Holds the usage boolean of an exercise.
+  \propbool{use\bang}
+    Holds a special usage boolean of an exercise, see
+    page~\pageref{property:print!}.
+  \propbool{used}
+    True if an exercise has been used at least once.  For an existing exercise
+    this is only false for exercises that have been collected
+    (\cf~section~\vref{sec:collecting-exercises}).
+  \propval{tags}{csv list of tags}
+    Holds the list of tags the exercise should be associated with.
+  \propval{topics}{csv list of topics}
+    Holds the list of topics the exercise should be associated with.
+  \propval{page}{text}
+    Holds the page counter value represenation of an exercise (\ie, what you
+    usually know as \cs*{thepage}).
+  \propval{page-value}{integer}
+    Holds the page counter value of an exercise (\ie, what you usually know as
+    \cs*{arabic}\Marg{page}).
+  \propval{section}{text}
+    Holds the section counter value represenation of an exercise (\ie, what
+    you usually know as \cs*{thesection}).
+  \propval{section-value}{integer}
+    Holds the section counter value of an exercise (\ie, what you usually know
+    as \cs*{arabic}\Marg{section}).
+  \propval{chapter}{text}
+    Holds the chapter counter value represenation of an exercise (\ie, what
+    you usually know as \cs*{thechapter}).  \emph{Only if a command
+      \cs*{chapter} \emph{and} a counter \code{chapter} exist.}
+  \propval{chapter-value}{integer}
+    Holds the chapter counter value of an exercise (\ie, what you usually know
+    as \cs*{arabic}\Marg{chapter}).  \emph{Only if a command \cs*{chapter}
+      \emph{and} a counter \code{chapter} exist.}
+\end{properties}
+
+Some of these \acsp*{prop} are fixed and cannot be set by the user.  Those
+include \property{id}, \property{counter}, and \property{counter-value}.  The
+others can be set using the optional argument of the exercise environment.
+
+\begin{example}
+  \begin{exercise}[subtitle={This is a subtitle},points=4,bonus-points=1]
+    An exercise where some properties have been set.
+  \end{exercise}
+\end{example}
+
+\subsection{Declaring Own Properties}
+
+\xsim\ offers the possibility to declare additional exercise properties:
+\begin{commands}
+  \command{DeclareExerciseProperty}[\barg\sarg\narg\marg{property}]
+    Declares the property \meta{property}.
+    
+    If used with the optional \barg\ star a unique property is defined which
+    means that each exercise must have a property value distinct from all
+    other exercises (all means all -- \emph{independent from the exercise type}).
+
+    If used with the optional \sarg\ a boolean property is defined which
+    means that it only should get the values \code{true} or \code{false} and
+    if used without value it gets the value \code{true} instead of an empty
+    value.  If any other value is used the property is set to
+    \code{false}.  A boolean option obviously cannot be unique.  The optional
+    \sarg\ takes precedence over the optional \barg, \ie, if both are present
+    the property is boolean \emph{but not} unique.
+
+    If used with the optional \narg\ a property is defined which won't get
+    updated through subsequent compilation runs but is only set when the
+    exercise is used.
+  \command{DeclareExercisePropertyAlias}[\marg{property 1}\marg{property 2}]
+    Declares \meta{property 1} to be an alias of \meta{property 2}.  This
+    means that each time \meta{property 2} is set \meta{property 1} will be
+    set to the same value \emph{unless} it has been set already.  As an
+    example: property \property{ID} is an alias of property \property{id}.
+\end{commands}
+
+This is better demonstrated with an example:
+\begin{example}
+  \begin{exercise}
+    \lipsum[4] % from package `lipsum'
+    \verb+\GetExerciseProperty{id}+: \GetExerciseProperty{id} \par
+    \verb+\GetExerciseAliasProperty{ID}+: \GetExerciseAliasProperty{ID} \par
+    \verb+\GetExerciseProperty{ID}+: \GetExerciseProperty{ID}
+  \end{exercise}
+  \begin{exercise}[ID=foo-bar]
+    \lipsum[4]
+    \verb+\GetExerciseProperty{id}+: \GetExerciseProperty{id} \par
+    \verb+\GetExerciseAliasProperty{ID}+: \GetExerciseAliasProperty{ID} \par
+    \verb+\GetExerciseProperty{ID}+: \GetExerciseProperty{ID}
+  \end{exercise}
+\end{example}
+
+The power of properties will get more clear when reading
+section~\vref{sec:styl-exerc-templ} about templates.
+
+\subsection{A Special Kind of Property: Exercise Goals}\label{sec:goals}
+
+Exercise goals are a generic concept in \xsim\ for exercise properties like
+\property{points} or \property{bonus-points}.  Those are properties which can
+(only) get a decimal number as value the sum of which is calculated and
+available (after a compilation) throughout the document.
+\begin{commands}
+  \command{DeclareExerciseGoal}[\marg{goal}]
+    Declare a new exercise goal named \meta{goal} and also a property called
+    \meta{goal}.
+  \command{TotalExerciseTypeGoal}[\marg{type}\marg{goal}\marg{singular}\marg{plural}]
+    Get the sum of goal \meta{goal} for all exercises of type \meta{type}.
+    \meta{singular} and \meta{plural} are placed after the sum in the input
+    stream depending on whether the sum equals~$1$ or not.
+    \command{TotalExerciseTypeGoals}[\marg{type}\marg{list of
+      goals}\marg{singular}\marg{plural}]
+    Get the sum of goal all goals in \meta{list of goals} for all exercises of
+    type \meta{type}.  The goal names in \meta{list of goals} must be
+    separated with \code{+}. \meta{singular} and \meta{plural} are placed
+    after the sum in the input stream depending on whether the sum equals~$1$
+    or not.
+  \command{TotalExerciseGoal}[\marg{goal}\marg{singular}\marg{plural}]
+    Get the sum of goal \meta{goal} for all exercises. \meta{singular} and
+    \meta{plural} are placed after the sum in the input stream depending on
+    whether the sum equals~$1$ or not.
+  \command{TotalExerciseGoals}[\marg{list of
+    goals}\marg{singular}\marg{plural}]
+    Get the sum of goal all goals in \meta{list of goals} for all exercises.
+    The goal names in \meta{list of goals} must be separated with
+    \code{+}. \meta{singular} and \meta{plural} are placed after the sum in
+    the input stream depending on whether the sum equals~$1$ or not.
+  \command{AddtoExerciseTypeGoal}[\marg{type}\marg{goal}\marg{value}]
+    Adds \meta{value} to the goal \meta{goal} of exercise type \meta{type}.
+  \command{AddtoExerciseTypeGoalPrint}[\marg{type}\marg{goal}\marg{value}%
+    \marg{singular}\marg{plural}]
+    Adds \meta{value} to the goal \meta{goal} of exercise type \meta{type}.
+    The value and -- depending on wether the value equals $1$ or not --
+    \meta{singular} or \meta{plural} are left in the input stream.
+  \command{AddtoExerciseGoal}[\marg{goal}\marg{value}]
+    Adds \meta{value} to the goal \meta{goal} of the current exercise
+    type. (To be used within exercises.)
+  \command{AddtoExerciseTypeGoalPrint}[\marg{goal}\marg{value}%
+    \marg{singular}\marg{plural}]
+    Adds \meta{value} to the goal \meta{goal} of the current exercise type.
+    The value and -- depending on wether the value equals $1$ or not --
+    \meta{singular} or \meta{plural} are left in the input stream. (To be used
+    within exercises.)
+  \command{ExerciseGoalValuePrint}[\marg{value}\marg{singular}\marg{plural}]
+    Print \meta{value} and -- depending on wether the value equals $1$ or not --
+    \meta{singular} or \meta{plural}.
+  \command{printgoal}[\marg{value}]
+    Print \meta{value} according to option \option{goal-print}.  Defined in
+    terms of \cs{ExerciseGoalValuePrint}.
+  \command{printpoints}[\marg{type}]
+    Print the sum of points for all exercises of type \meta{type} followed by
+    an appropriate translation of the words \enquote{point} or
+    \enquote{points}, respectively\footnote{See section~\vref{sec:exerc-transl}
+      for details on the definition and usage of language dependent words.}.
+    Defined in terms of \cs{TotalExerciseTypeGoal}.
+  \command{printtotalpoints}
+    Print the sum of points for all exercises followed by an appropriate
+    translation of the words \enquote{point} or \enquote{points},
+    respectively.  Defined in terms of \cs{TotalExerciseGoal}.
+  \command{addpoints}[\sarg\marg{value}]
+    Adds \meta{value} to the points of the current exercise type. (To be used
+    within exercises.)  Prints the value followed by an appropriate
+    translation of the words \enquote{point} or \enquote{points},
+    respectively.  The starred version prints nothing.  Defined in terms of
+    \cs{AddtoExerciseGoal} and \cs{AddtoExerciseGoalPrint}.
+  \command{points}[\marg{value}]
+    Print \meta{value}followed by an appropriate translation of the words
+    \enquote{point} or \enquote{points}, respectively.  Defined in terms of
+    \cs{ExerciseGoalValuePrint}.
+  \command{printbonus}[\marg{type}]
+    Print the sum of bonus points for all exercises of type \meta{type}
+    followed by an appropriate translation of the words \enquote{point} or
+    \enquote{points}, respectively.  Defined in terms of
+    \cs{TotalExerciseTypeGoal}.
+  \command{printtotalbonus}
+    Print the sum of bonus points for all exercises followed by an appropriate
+    translation of the words \enquote{point} or \enquote{points},
+    respectively.  Defined in terms of \cs{TotalExerciseGoal}.
+  \command{addbonus}[\sarg\marg{value}]
+    Adds \meta{value} to the bonus points of the current exercise type. (To be
+    used within exercises.)  Prints the value followed by an appropriate
+    translation of the words \enquote{point} or \enquote{points},
+    respectively.  The starred version prints nothing.  Defined in terms of
+    \cs{AddtoExerciseGoal} and \cs{AddtoExerciseGoalPrint}.
+\end{commands}
+
+The two existing goals are defined with
+\begin{sourcecode}
+  \DeclareExerciseGoal{points}
+  \DeclareExerciseGoal{bonus-points}
+\end{sourcecode}
+
+When goal values are printed the decimal number is fed to a function which can
+be changed using the following option:
+\begin{options}
+  \keyval{goal-print}{code}\Default{\#1}
+    How to format goal values.  Use \code{\#1} to refer to the actual number.
+\end{options}
+
+At last some examples for a custom command: let's say you want a command which
+prints the complete sum for all exercises of all exercise types of both
+\property{points} \emph{and} \property{bonus-points} added up:
+\begin{sourcecode}
+  \NewDocumentCommand\printsumofpointsandbonus{}{%
+    \TotalExerciseGoals{points+bonus-points}
+      {\,\XSIMtranslate{point}}
+      {\,\XSIMtranslate{points}}%
+  }
+\end{sourcecode}
+Here is how you could mimick the command \cs*{totalpoints} from
+\pkg{exsheets}:
+\begin{sourcecode}
+  \NewDocumentCommand\pointsandbonus{}{%
+    \TotalExerciseGoal{points}{}{}%
+    \IfExerciseGoalsSumF{bonus-points}{=0}
+      {\,(+\,\TotalExerciseGoal{bonus-points}{}{})}%
+    \,\XSIMtranslate{points}%
+  }
+\end{sourcecode}
+
+
+\subsection{A Special Kind of Property: Exercise Tags}\label{sec:tags}
+
+Exercise tags are a generic concept in \xsim\ for exercise properties like
+\property{tags} or \property{topics}.  Those are properties which can (only)
+get a csv list of strings as value.  Those strings can be used to selectively
+use exercises.  See section~\vref{sec:using-printing} for details on
+\emph{usage} of exercises and the difference to \emph{printing} an exercise
+and how to use exercise tags for selection.
+\begin{commands}
+  \command{DeclareExerciseTagging}[\marg{tag}]
+    This defines an exercise tagging group named \meta{tag}.  It also defines a
+    property named \meta{tag}.  In addition two options are defined: an option
+    named \code{\meta{tag}} which can be used for selection and an boolean
+    option \code{\meta{tag}/ignore-untagged}.
+\end{commands}
+The two existing tagging groups have been defined and preset with the
+following code:
+\begin{sourcecode}
+  \DeclareExerciseTagging{tags}
+  \DeclareExerciseTagging{topics}
+  \xsimsetup{tags/ingore-untagged=false}
+\end{sourcecode}
+This means that these options are available:
+\begin{options}
+  \keyval{tags}{csv list of tags}
+    Choose the set of tags whose associated exercises should be printed.
+  \keyval{topics}{csv list of topics}
+    Choose the set of tags whose associated exercises should be printed.
+  \keybool{ignore-tagging}\Module{tags}\Default{false}
+    If set to true exercises with no tags will be printed even if tags have
+    been chosen with the option \option{tags}.
+  \keybool{ignore-tagging}\Module{topics}\Default{true}
+    If set to true exercises with no topics will be printed even if tags have
+    been chosen with the option \option{topics}.
+\end{options}
+
+It may happen that you choose certain tags for printing and want one or two
+exercises to be printed or used even if they don't match the tagging
+criteria.  For this reason two additional properties exist which can be set to
+an exercise:\label{property:print!}
+\begin{properties}
+  \propbool{print\bang}
+    If set to true the exercise will be printed (and thus used) regardless of
+    other conditions.
+  \propbool{use\bang}
+    If set to true the exercise will be used regardless of other conditions.
+\end{properties}
+
+\section{Using and Printing an Exercise}\label{sec:using-printing}
+\subsection{What the Environments do}
+
+When an exercise is started with \environ{exercise} (or other environments
+defined through \cs{DeclareExerciseType}) then different things happen
+depending on different settings:
+\begin{itemize}
+  \item If the \emph{insert mode} is active nothing happens, see
+    section~\vref{sec:collecting-exercises} for details on this.
+  \item Else the id integer is incremented.
+  \item If the exercise is \emph{used} the corresponding counter is stepped
+    and the exercise is added to the \enquote{use list}.  The properties
+    \property{counter} and \property{use} are updated accordingly.
+  \item If an exercise is \emph{printed} then it is also \emph{used}. An
+    exercise that isn't used cannot be printed.  Being printed means two
+    things: being added to the \enquote{print list} and being typeset at the
+    position where the exercise is placed in the source file.  If an exercise
+    is \emph{not printed but used} it means that the counter will be stepped.
+    This can be useful for creating an exercise sheet only containing the
+    solutions for some exercises.
+  \item If an exercise is printed certain hooks and template code is inserted
+    around the environment body.
+\end{itemize}
+
+\begin{example}
+  \begin{exercise}[print=false]
+    This exercise will not be printed but the exercise counter will be
+    incremented nonetheless. Its solution will be printed in the list of
+    solutions.
+  \end{exercise}
+  \begin{solution}
+    The solution of the exercise that has not been printed.
+  \end{solution}
+\end{example}
+
+The schematic structure of an exercise is shown in
+figure~\vref{fig:schematic-structure}.
+
+\begin{figure}
+  \centering
+  \begin{tikzpicture}
+    \node[draw,minimum width=.7\linewidth] at (0,0)  {pre hook};
+    \node[draw,minimum width=.7\linewidth] at (0,-1) {begin template code};
+    \node[draw,minimum width=.7\linewidth] at (0,-2) {begin hook};
+    \node[draw,minimum width=.7\linewidth] at (0,-3) {environment body};
+    \node[draw,minimum width=.7\linewidth] at (0,-4) {end hook};
+    \node[draw,minimum width=.7\linewidth] at (0,-5) {end template code};
+    \node[draw,minimum width=.7\linewidth] at (0,-6) {post hook};
+  \end{tikzpicture}
+  \caption{Schematic structure of an exercise or solution.}\label{fig:schematic-structure} 
+\end{figure}
+
+\subsection{Environment Options \& Hooks}\label{sec:environment-options-hooks}
+
+For each exercise type there are the following options for both environments,
+the environments' names are the module names for the options (here using the
+\enquote{exercise} type):
+\begin{options}
+  \keybool{print}\Module{exercise}\Default{true}
+    Determines if exercises of type \enquote{exercise} are printed.
+  \keybool{use}\Module{exercise}\Default{true}
+    Determines if exercises of type \enquote{exercise} are used.
+  \keyval{within}{counter}\Module{exercise}\Default
+    Adds the exercise counter to the reset list of the counter
+    \meta{counter}.  \emph{Beware that if the counter is a shared counter
+      this will affect \emph{all objects} using this counter!}
+  \keyval{the-counter}{code}\Module{exercise}
+    An interface for redefining the counter representation command
+    \cs*{the\meta{counter}}.
+  \keyval{template}{template}\Module{exercise}
+    An interface for \cs{SetExerciseParameter}\Marg{exercise}%
+    \Marg{exercise-template}\marg{template}.
+  \keyval{template}{template}\Module{solution}
+    An interface for \cs{SetExerciseParameter}\Marg{exercise}%
+    \Marg{solution-template}\marg{template}.
+  \keyval{name}{name}\Module{exercise}
+    An interface for \cs{SetExerciseParameter}\Marg{exercise}%
+    \Marg{exercise-name}\marg{name}.
+  \keyval{name}{name}\Module{solution}
+    An interface for \cs{SetExerciseParameter}\Marg{exercise}%
+    \Marg{solution-name}\marg{name}.
+  \keyval{pre-hook}{code}\Module{exercise}\Default
+    The code for the \emph{pre exercise hook} for exercises of the type
+    \enquote{exercise}.
+  \keyval{begin-hook}{code}\Module{exercise}\Default
+    The code for the \emph{begin exercise hook} for exercises of the type
+    \enquote{exercise}.
+  \keyval{end-hook}{code}\Module{exercise}\Default
+    The code for the \emph{end exercise hook} for exercises of the type
+    \enquote{exercise}.
+  \keyval{post-hook}{code}\Module{exercise}\Default
+    The code for the \emph{post exercise hook} for exercises of the type
+    \enquote{exercise}.
+  \keybool{print}\Module{solution}\Default{false}
+    Determines if solutions of type \enquote{exercise} are printed.
+  \keyval{pre-hook}{code}\Module{solution}\Default
+    The code for the \emph{pre solution hook} for solutions of the type
+    \enquote{exercise}.
+  \keyval{begin-hook}{code}\Module{solution}\Default
+    The code for the \emph{begin solution hook} for solutions of the type
+    \enquote{exercise}.
+  \keyval{end-hook}{code}\Module{solution}\Default
+    The code for the \emph{end solution hook} for solutions of the type
+    \enquote{exercise}.
+  \keyval{post-hook}{code}\Module{solution}\Default
+    The code for the \emph{post solution hook} for solutions of the type
+    \enquote{exercise}.
+  % TODO
+\end{options}
+
+\subsection{(Re-) Inserting a Certain Exercise}
+If you know type and \property{id} of an exercise you can (re-)insert every
+existing exercise, \ie, every exercise whose external file exists.
+\begin{commands}
+  \command{printexercise}[\marg{type}\marg{id}]
+    Inserts the exercise of type \meta{type} with the \property{id}
+    \meta{id}.
+\end{commands}
+\begin{example}
+  \printexercise{exercise}{5}
+\end{example}
+
+\section{Collecting Exercises}\label{sec:collecting-exercises}
+
+\subsection{Background}
+\xsim\ knows the concept of \enquote{exercise collections}.  A collection of
+exercises can be useful when you want to print a certain group of exercises
+several times.  Each collection must have a unique name with which you can
+refer to the corresponding collection.  A collection is realized by declaring
+the collection and by surrounding the exercises belonging to the collection
+with a certain pair of commands (this is explained in the next section).
+
+Let's say you have several files of math exercises where one only contains
+geometry exercises and another only calculus exercises and so on.  Surrounding
+the \cs*{input} of each file with said pair of commands for a certain
+collection all exercises of the corresponding file now are a collection which
+then can be printed at once whereever you want the collection of exercises to
+be printed.  By choosing certain tags (see section~\vref{sec:tags}) inside
+each collection you could even cherry-pick exercises from the external file.
+
+\subsection{Usage}
+\emph{A collection must be declared in the preamble.}  Using a pair of
+commands explained below exercises between those commands are added to the
+corresponding collection but not printed.  After a collection is completed the
+collection can be printed as often as needed.
+\begin{commands}
+  \command{DeclareExerciseCollection}[\marg{collection name}]
+    Define a new collection \meta{collection name} in the document preamble.
+  \command{collectexercisestype}[\marg{collection name}\marg{exercise type}]
+    Opens the collection \meta{collection name} which now collects all
+    exercises of type \meta{exercise type} until the collection is closed with
+    \cs{collectexercisesstop}.  Collections of other types are not
+    collected\footnote{This command starts a group with
+      \cs*{begingroup}!}.
+  \command{collectexercises}[\marg{collection name}]
+    Opens the collection \meta{collection name} which now collects all
+    exercises until the collection is closed with
+    \cs{collectexercisesstop}\footnote{This command starts a group with
+      \cs*{begingroup}!}.
+  \command{collectexercisesstop}[\marg{collection name}]
+    Closes the collection \meta{collection name}\footnote{This command ends
+      a group with \cs*{endgroup}!}.
+  \command{printcollection}[\oarg{options}\marg{collection name}]
+    Prints the collection \meta{collection name}, \ie, all exercises collected
+    earlier.  This command cannot be used before the corresponding collection
+    has been closed correctly.
+\end{commands}
+
+Valid options are the following:
+\begin{options}
+  \keybool{headings}\Module{print-collection}\Default{false}
+    If true a heading for each exercise type is inserted.
+  \keyval{headings-template}{template}\Module{print-collection}\Default{collection}
+    The heading template used when \keyis{headings}{true}.
+  \keychoice{print}{exercises,solutions,both}\Module{print-collection}\Default{exercises}
+    Determines wether \cs{printcollection} prints the exercises or the
+    solutions of the collection.  When you choose \code{both} exercises and
+    solutions are printed alternately.
+\end{options}
+
+Those options can also be set via \cs{xsimsetup} using the module
+\module{print-collection}.
+
+\begin{bewareofthedog}
+  Please be aware that exercises are not used or printed while they are
+  collected.  Nonetheless the property \property{use} is set to \code{true}
+  (so that solutions can be printed even if the exercises are not) and the
+  property \property{print} is set to \code{false}.  Also their counters are
+  \emph{not stepped} during the process.  This only happens when they are
+  printed the first time, \cf~the \property{used} property.  At that time
+  also the properties \property{page}, \property{section} and
+  \property{chapter} are set and the property \property{print} is set to
+  \code{true}.
+\end{bewareofthedog}
+
+The usage should be clear:
+\begin{example}
+  \collectexercises{foo}
+  \begin{exercise}
+    This exercise is added to the collection `foo'.
+  \end{exercise}
+  \begin{exercise}
+    This exercise is also added to the collection `foo'.
+  \end{exercise}
+  \begin{exercise}
+    So is this.
+  \end{exercise}
+  \begin{exercise}
+    As well as this one.
+  \end{exercise}
+  \collectexercisesstop{foo}
+\end{example}
+Once the collection is closed it can be printed:
+\begin{example}
+  \printcollection{foo}
+\end{example}
+
+You can open several collections at the same time:
+\begin{sourcecode}
+  \collectexercises{foo}
+    ...
+  \collectexercisestype{bar}{exercises}
+    ...
+  \collectexercisesstop{bar}
+    ...
+  \collectexercisesstop{foo}
+\end{sourcecode}
+Exercises will be added to each open collection.
+
+There is one generic collection called \enquote{\code{all exercises}}.  As the
+name already suggests it will hold all exercises.  So if you say
+\begin{sourcecode}
+  \printcollection{all exercises}
+\end{sourcecode}
+all exercises will be printed.
+
+\begin{bewareofthedog}
+  If you use \cs*{label}s inside of exercises and you print exercises more
+  than once in your document (by reusing a collection for example) you will
+  get
+\begin{sourcecode}
+  LaTeX Warning: There were multiply-defined labels.
+\end{sourcecode}
+  Equally if you have environments like \environ{equation} which step a
+  counter inside an exercise or solution the counter will be stepped each time
+  the exercise is used.
+\end{bewareofthedog}
+
+At last now an example using external files, collections and tags:
+\begin{sourcecode}
+  % preamble:
+  % \DeclareExerciseCollection{foo-easy}
+  % \DeclareExerciseCollection{foo-medium}
+  % \DeclareExerciseTagging{difficulty}
+
+  % document:
+  \collectexercises{foo-easy}
+  \xsimsetup{difficulty=easy}
+  \input{foo.tex}
+  \collectexercisesstop{foo-easy}
+  % collection `foo-easy' now contains all exercises of file `foo.tex' tagged
+  % with `difficulty=easy'
+
+  \collectexercises{foo-medium}
+  \xsimsetup{difficulty=medium}
+  \input{foo.tex}
+  \collectexercisesstop{foo-medium}
+  % collection `foo-medium' now contains all exercises of file `foo.tex'
+  % tagged with `difficulty=medium'
+\end{sourcecode}
+
+\begin{bewareofthedog}
+  The recommended usage is similar to the last example.  Actually a collection
+  can be printed \emph{before} it is opened, too.  (This needs \emph{at least}
+  two compilations, though.)  However, it is safer printing a collection only
+  once and only \emph{after it has been collected}.  No guaranties are given
+  that properties are set correctly if you use the collection before.  You
+  usually also will make sure that the exercises in a collection are unique,
+  \ie, that an exercises is not part of several collections -- at least not if
+  both collections are printed in the same document.
+\end{bewareofthedog}
+
+\section{Printing Random Exercises From a Collection}
+\xsim\ provides the possibility of selecting random exercises from a
+collection (\cf~section~\vref{sec:collecting-exercises}).
+\begin{commands}
+  \command{printrandomexercises}[\oarg{options}\marg{number}]
+    This command prints \meta{number} random exercises from the collection
+    chosen with option \option{collection}, see below.  When this command is
+    used it generates a random list of integers which is written to the
+    \code{aux} file.  On the subsequent compilations the according exercises
+    are printed.  \emph{If you want to regenerate the random list you have to
+      delete the \code{aux} file before compiling.}
+\end{commands}
+Valid options for this command are:
+\begin{options}
+  \keybool{sort}\Module{random}\Default{true}
+    Determines wether the random chosen exercises should be sorted according
+    to their order of definition in the collection or not.
+  \keyval{collection}{collection}\Module{random}\Default{all exercises}
+    The collection from which the exercises are to be chosen from.
+  \keyval{exclude}{csv list of ids}\Module{random}
+    A list of \property{id}s or \property{ID}s of exercises \emph{not} to be
+    chosen.
+  \keychoice{print}{exercises,solutions,both}\Module{random}\Default{exercises}
+    Determines wether \cs{printrandomexercises} prints the exercises or the
+    solutions.  When you choose \code{both} exercises and solutions are
+    printed alternately.
+\end{options}
+
+\begin{example}
+  \printrandomexercises[collection=foo]{2}
+\end{example}
+
+The example above of course doesn't make much sense but if have a collection
+which collects exercises from an external file and the exercise haven't been
+printed in the document before then you will get a list of subsequently
+numbered exercises.
+
+\section{Printing Solutions}\label{sec:printing-solutions}
+
+There are different commands for printing the solutions to exercises:
+\begin{commands}
+  \command{printsolutionstype}[\sarg\oarg{options}\marg{exercise type}]
+    Prints the solutions of all used exercises of type \meta{exercise type}.
+    The starred version only prints the solutions of all printed exercises of
+    type \meta{exercise type}.
+  \command{printsolutions}[\sarg\oarg{options}]
+    Prints the solutions of all used exercises of all types ordered by type.
+    The starred version only prints the solutions of all printed exercises of
+    all types.
+  \command{printallsolutions}[\sarg\oarg{options}]
+    Prints the solutions of all used exercises of all types ordered by
+    appearance in the document.  The starred version only prints the solutions
+    of all printed exercises of all types.
+  \command{printsolution}[\oarg{options}\marg{type}\marg{id}]
+    Prints the solution of the exercise of type \meta{type} with the
+    \property{id} \meta{id}.
+\end{commands}
+
+\begin{example}
+  \printsolutionstype{exercise}
+\end{example}
+
+The options can be diveded into two groups.  The ones in the first group
+modify the layout.
+\begin{options}
+  \keybool{headings}\Default{true}
+    If true a heading for each exercise type is inserted.
+  \keyval{headings-template}{template}\Default{default}
+    The heading template used when \keyis{headings}{true}.
+\end{options}
+
+The ones in the second group set conditions selecting which solutions are
+printed.  If you combine those conditions a solution is printed if it meets
+either of the conditions.
+\begin{options}
+  \keychoice{section}{\default{true},false,\meta{integer}}\Default{false}
+    If you set \keyis{section}{true} only solutions of exercises of the
+    current section are printed.  If you set \keyis{section}{4} only solutions
+    of exercises in a section with number~$4$ are printed.
+  \keychoice{chapter}{\default{true},false,\meta{integer}}\Default{false}
+    If you set \keyis{chapter}{true} only solutions of exercises of the
+    current chapter are printed.  If you set \keyis{chapter}{4} only solutions
+    of exercises in a chapter with number~$4$ are printed.
+  \keychoice{collection}{false,\meta{collection name}}\Default{false}
+    If used only solutions of exercises belonging to collection
+    \meta{collection name} are printed.
+\end{options}
+
+The conditions can be combined.  The following call will only print solutions
+from exercises in section~3 of chapter~2:
+\begin{sourcecode}
+  \printsolutions[chapter=2,section=3]
+\end{sourcecode}
+
+\begin{bewareofthedog}
+  The selection per section or per chapter relies on the \emph{counter
+    numbers} of the sections or chapters, respectively.  This means if section
+  numbers are reset (\eg\ by \cs*{chapter} or \cs*{appendix}) and you have
+  exercises from \emph{different} sections with \emph{the same section number}
+  the solutions of \emph{all those exercises} will be printed.  This means you
+  only should use the \option{section} selection when section are the top
+  document level headings (apart from parts) and you have no exercises in the
+  appendix.  Similar considerations are valid for the \option{chapter}
+  selection.
+\end{bewareofthedog}
+
+All options can also be set via \cs{xsimsetup} using the module
+\module{print-solutions}.
+
+\begin{example}
+  \printsolutions[section=4,headings-template=per-section]
+\end{example}
+
+\begin{example}
+  \printsolution{exercise}{5}
+\end{example}
+
+\section{Grading Tables}\label{sec:grading-tables}
+When you create exercises it may not only be desirable to be able to add
+points and bonus-points to a question (see section~\vref{sec:goals} about
+exercise goals) but also to be able to output a grading table. \xsim\ has
+built-in means for this.
+\begin{commands}
+  \command{gradingtable}[\oarg{options}]
+    Print a grading table.
+\end{commands}
+Valid options for this command are
+\begin{options}
+  \keyval{template}{template}\Default{default}
+    Choose the template used for the grading table.
+  \keyval{type}{exercise type}\Default
+    Choose the exercise type for which the table is printed.
+\end{options}
+Both option defaults can be changed with \cs{xsimsetup} setting the options
+using \module{grading-table}:
+\begin{sourcecode}
+  \xsimsetup{
+    grading-table/template = default*
+  }
+\end{sourcecode}
+
+An example:
+\begin{example}
+  \gradingtable[type=exercise]
+\end{example}
+
+Or using the \enquote{\code{default*}} template:
+\begin{example}
+  \gradingtable[template=default*,type=exercise]
+\end{example}
+
+Available templates and how to define new ones are explained in
+sections~\vref{sec:grad-table-templ} and~\vref{sec:template-examples}.  \xsim\
+per default provides two templates \enquote{\code{default}} and
+\enquote{\code{default*}}, the first one has a vertical layout, the second a
+horizontal layout.  Both templates can be used per type like in the examples
+above or for all types at once by leaving the specification \option{type}
+away:
+\begin{example}
+  \gradingtable
+\end{example}
+
+\section{Styling the Exercises -- Templates}\label{sec:styl-exerc-templ}
+
+\subsection{Background}
+Whenever \xsim\ outputs something to be typeset it uses so-called templates
+for the task.  \xsim\ knows of three different kinds of templates:
+\begin{itemize}
+  \item environment templates (see section~\vref{sec:envir-templ}),
+  \item heading templates (see section~\vref{sec:heading-templates}) and
+  \item grading table templates (see section~\vref{sec:grad-table-templ})
+\end{itemize}
+
+The most important one for the styling of the exercises are the environment
+templates.  Those templates give you complete control over the look and
+arrangement of an exercise.  To be able to do this \xsim\ provides a large
+number of commands which can be used only inside template
+definitions\footnote{The last sentence is wrong: those commands can be used
+  anywhere but most of them only give useful results inside of templates.}.
+Those commands are explained in the next section.  Their usage will hopefully
+become clear in the examples in section~\vref{sec:template-examples}. Having
+full control over the layout comes at a price: you need to be able to program
+yourself in order to achieve certain layouts\footnote{I plan to incorporate
+  the most common layouts -- and maybe some fancy ones, too -- in the examples
+  section~\vref{sec:template-examples} but at the time of writing this is still
+  up in the air.}.
+
+\subsection{Commands for Usage in Template Definitions}
+\subsubsection{Goals}
+\begin{commands}
+  \command{IfExerciseGoal\TF}[\marg{goal}\marg{relation and
+    value}\marg{true}\marg{false}]
+    Checks the sum of goal \meta{goal} against \meta{relation and value}.
+  \command{IfExerciseGoalSingular\TF}[\marg{goal}\marg{true}\marg{false}]
+    Checks if the value of the goal \meta{goal} of the current exercise
+    equals~$1$.  This is the same as \\
+    \cs{IfExerciseGoalTF}\marg{goal}\Marg{=1}\marg{true}\marg{false}.
+  \command{IfExerciseTypeGoalsSum\TF}[\marg{type}\marg{list of
+    goals}\marg{relation and value}\marg{true}\marg{false}]
+    Ckecks the sum of all goals in \meta{list of goals} for the exercises of
+    type \meta{type} against \meta{relation and value}.
+  \command{IfExerciseGoalsSum\TF}[\marg{type}\marg{list of
+    goals}\marg{relation and value}\marg{true}\marg{false}]
+    Ckecks the sum of all goals in \meta{list of goals} for all exercises of
+    all types against \meta{relation and value}.
+  \command{TotalExerciseTypeGoal}[\marg{goal}\marg{type}\marg{singular}\marg{plural}]
+    Print the sum of goal \meta{goal} for the exercises of type \meta{type}
+    and append \meta{singular} or \meta{plural} depending on wether the sum
+    equals~$1$ or not.
+  \command{TotalExerciseGoal}[\marg{goal}\marg{singular}\marg{plural}]
+    Print the sum of goal \meta{goal} for all exercises of all types
+    and append \meta{singular} or \meta{plural} depending on wether the sum
+    equals~$1$ or not.
+\end{commands}
+
+\subsubsection{Properties}
+\begin{commands}
+  \expandable\command{IfExercisePropertyExist\TF}[\marg{property}\marg{true}%
+  \marg{false}]
+    Tests wether an exercise property with the name \meta{property} is defined.
+  \command{IfExercisePropertySet\TF}[\marg{property}\marg{true}\marg{false}]
+    Tests wether the exercise property \meta{property} has been set for the
+    current exercise.
+  \expandable\command{GetExerciseProperty}[\marg{property}]
+    Retrieves the value of the property \meta{property} for the current
+    exercise.
+  \command{GetExerciseProperty\TF}[\marg{property}\marg{true}\marg{false}]
+    Tests wether the exercise property \meta{property} has been set for the
+    current exercise.  Inside the \meta{true} branch you can refer to the
+    retrieved value either with \code{\#1} or with \cs{PropertyValue}.
+    \emph{This command expands its contents inside a group.}
+  \command{GetExerciseIdForProperty}[\marg{property}\marg{value}]
+    Retrieves the property \property{id} of the exercise where the property
+    \meta{property} has the value \meta{value}.  \emph{This only works for
+      \emph{unique} properties!}
+  \command{GetExerciseTypeForProperty}[\marg{property}\marg{value}]
+    Retrieves the property \property{type} of the exercise where the
+    property \meta{property} has the value \meta{value}.  \emph{This only
+      works for \emph{unique} properties!}
+  \command{SetExerciseProperty}[\marg{type}\marg{id}\marg{property}\marg{value}]
+    Set the property \meta{property} of exercise of type \meta{type} and id
+    \meta{id} to \meta{value}.
+  \expandable\command{IfExerciseBooleanProperty\TF}[\marg{property}%
+    \marg{true}\marg{false}]
+    Checks wether the boolean property \meta{property} has value \code{true}
+    or \meta{false} and leaves the corresponding argument in the input
+    stream.  Gives an error if \meta{property} is not a boolean property.
+  \expandable\command{GetExerciseAliasProperty}[\marg{property}]
+    Retrieves the value of the property of which \meta{property} is an alias
+    of for the current exercise.
+  \command{SaveExerciseProperty}[\marg{property}\meta{macro}]
+    Saves the value of the property \meta{property} for the current
+    exercise in macro \meta{macro}.
+  \command{GlobalSaveExerciseProperty}
+    Globally saves the value of the property \meta{property} for the current
+    exercise in macro \meta{macro}.
+  \command{ExercisePropertyIfSet\TF}[\marg{type}\marg{id}\marg{property}%
+    \marg{true}\marg{false}]
+    Test if the property \meta{property} has been set for the exercise of type
+    \meta{type} with id \meta{id}.
+  \expandable\command{ExercisePropertyGet}[\marg{type}\marg{id}\marg{property}]
+    Retrieves the value of the property \meta{property} for the exercise of type
+    \meta{type} with id \meta{id}.
+  \expandable\command{ExercisePropertyGetAlias}[\marg{type}\marg{id}\marg{property}]
+    Retrieves the value of the property of which \meta{property} is an alias
+    of for the exercise of type \meta{type} with id \meta{id}.
+  \command{ExercisePropertySave}[\marg{type}\marg{id}\marg{property}\meta{macro}]
+    Saves the value of the property \meta{property} for the exercise of type
+    \meta{type} with id \meta{id} in macro \meta{macro}.
+  \command{ExercisePropertyGlobalSave}[\marg{type}\marg{id}\marg{property}\meta{macro}]
+    Globally saves the value of the property \meta{property} for the exercise
+    of type \meta{type} with id \meta{id} in macro \meta{macro}.
+\end{commands}
+
+\subsubsection{Parameters}
+\begin{commands}
+  \expandable\command{GetExerciseParameter}[\marg{parameter}]
+    Retrieves the value of the parameter \meta{paramater} for the current exercise.
+  \expandable\command{GetExerciseName}
+    Retrieves the value of the parameter \parameter{exercise-name} for the
+    current exercise or of the parameter \parameter{solution-name} for the
+    current solution.
+  \expandable\command{ExerciseParameterGet}[\marg{type}\marg{id}\marg{parameter}]
+    Retrieves the value of the parameter \meta{parameter} for the exercise of type
+    \meta{type} with id \meta{id}.
+\end{commands}
+
+\subsubsection{Tags}
+\begin{commands}
+  \command{ForEachExerciseTag}[\marg{type}\marg{code}]
+    Loops over all tags of tag type \meta{type} for the current exercise
+    applying \meta{code} each time.  Inside \meta{code} you can refer to the
+    corresponding tag with \code{\#1}.
+  \command{ListExerciseTags}[\marg{type}\marg{between}]
+    Lists all tags of tag type \meta{type} for the current exercise using
+    \meta{between} as a separator.
+  \command{UseExerciseTags}[\marg{type}\marg{between
+    two}\marg{between}\marg{between last two}]
+    Lists all tags of tag type \meta{type} for the current exercise using
+    \meta{between} as a separator and \meta{between last two} as separator
+    between the last two tags of the list.  If the list only consists of two
+    tags \meta{between two} is used as separator.
+\end{commands}
+
+\subsubsection{Further Commands for Usage in Template Definitions}
+\begin{commands}
+  \expandable\command{ExerciseType}
+    Can be used to refer to the current exercise type.
+  \expandable\command{ExerciseID}
+    Can be used to refer to the current exercise id.
+  \expandable\command{ExerciseCollection}
+    Can be used in certain templates to refer to the collection that is
+    currently inserted.
+  \expandable\command{numberofusedexercises}
+    Holds the total number of used exercises.  Useful in table template
+    definitions.
+  \expandable\command{ExerciseTableType}[\marg{code}]
+    In table template definitions this macro either expands to the given
+    exercise type or -- if no type has been given -- to \meta{code}.
+  \expandable\command{IfInsideSolution\TF}[\marg{true}\marg{false}]
+    Tests if the template is used inside a solution environment or not.
+  \expandable\command{IfPrintSolution\TF}[\marg{true}\marg{false}]
+    Tests if the option \option{print} for the solutions of the current
+    \cs{ExerciseType} is set to \code{true} or \code{false}.
+  \command{ForEachPrintedExerciseByType}[\marg{code}]
+    Loops over each \emph{printed} exercise ordered by the exercise types and
+    within each type by id.  Inside \meta{code} you can refer to several
+    properties of the corresponding exercise:
+    \begin{itemize}
+      \item \code{\#1}: the type of the exercise
+      \item \code{\#2}: the id of the exercise
+      \item \code{\#3}: the \property{counter} property of the exercise
+      \item \code{\#4}: the \property{subtitle} property of the exercise
+      \item \code{\#5}: the \property{points} property of the exercise
+      \item \code{\#6}: the \property{bonus-points} property of the exercise
+    \end{itemize}
+  \command{ForEachUsedExerciseByType}[\marg{code}]
+    Loops over each \emph{used} exercise ordered by the exercise types and
+    within each type by id.  Inside \meta{code} you can refer to several
+    properties of the corresponding exercise:
+    \begin{itemize}
+      \item \code{\#1}: the type of the exercise
+      \item \code{\#2}: the id of the exercise
+      \item \code{\#3}: the \property{counter} property of the exercise
+      \item \code{\#4}: the \property{subtitle} property of the exercise
+      \item \code{\#5}: the \property{points} property of the exercise
+      \item \code{\#6}: the \property{bonus-points} property of the exercise
+    \end{itemize}
+  \command{ForEachPrintedExerciseByID}
+    Loops over each \emph{printed} exercise order by the exercise id.  Inside
+    \meta{code} you can refer to several properties of the corresponding
+    exercise:
+    \begin{itemize}
+      \item \code{\#1}: the type of the exercise
+      \item \code{\#2}: the id of the exercise
+      \item \code{\#3}: the \property{counter} property of the exercise
+      \item \code{\#4}: the \property{subtitle} property of the exercise
+      \item \code{\#5}: the \property{points} property of the exercise
+      \item \code{\#6}: the \property{bonus-points} property of the exercise
+    \end{itemize}
+  \command{ForEachUsedExerciseByID}
+    Loops over each \emph{used} exercise order by the exercise id.  Inside
+    \meta{code} you can refer to several properties of the corresponding
+    exercise:
+    \begin{itemize}
+      \item \code{\#1}: the type of the exercise
+      \item \code{\#2}: the id of the exercise
+      \item \code{\#3}: the \property{counter} property of the exercise
+      \item \code{\#4}: the \property{subtitle} property of the exercise
+      \item \code{\#5}: the \property{points} property of the exercise
+      \item \code{\#6}: the \property{bonus-points} property of the exercise
+    \end{itemize}
+  \expandable\command{XSIMtranslate}[\marg{keyword}]
+    Delivers the translation of \meta{keyword} according to the current
+    document language (in the meaning of a \pkg{babel}~\cite{pkg:babel} or
+    \pkg{polyglossia}~\cite{pkg:polyglossia} language).  Existing keywords and
+    keyword translations (and how to add new ones) are explained in
+    section~\vref{sec:exerc-transl}.
+  \command{XSIMexpandcode}[\marg{code}]
+    Expands \meta{code} like \cs*{edef} does and leaves the result in the
+    input stream.
+  \expandable\command{XSIMifchapter\TF}[\marg{true}\marg{false}]
+    Returns \meta{true} if both a macro \cs*{chapter} and a counter
+    \code{chapter} are defined and \meta{false} otherwise.
+  \command{XSIMmixedcase}[\marg{code}]
+    Converts the full expansion\footnote{This is a \cs*{romannumeral}
+      expansion~\cite{texsx:romannumeral}.\label{fn:romannumeral}} of
+    \meta{code} to mixed case: \\
+    \verbcode+\XSIMmixedcase{this is some text}+ \XSIMmixedcase{this is some
+      text} \\
+    \emph{This command expands \meta{code} before converting it}.
+  \command{XSIMputright}[\meta{macro}\marg{code}]
+    Extends the macro definition of \meta{macro} with \meta{code} putting it
+    to the right.  This is more or less a local version of the LaTeX kernel
+    macro \cs*{g@addto@macro}.
+  \expandable\command{XSIMifeq\TF}[\marg{code 1}\marg{code
+    2}\marg{true}\marg{false}]
+    Checks if the full expansion\footref{fn:romannumeral} of \meta{code 1} and
+    \meta{code 2} is the same tokenlist.
+  \expandable\command{XSIMifblank\TF}[\marg{code}\marg{true}\marg{false}]
+    Checks if the full expansion\footref{fn:romannumeral} of \meta{code} is
+    blank (\ie, if it is empty or only consists of spaces). 
+\end{commands}
+
+\subsection{Declaring Templates}
+\subsubsection{Environment Templates}\label{sec:envir-templ}
+\begin{commands}
+  \command{DeclareExerciseEnvironmentTemplate}[\marg{name}\marg{begin
+    code}\marg{end code}]
+    Declare the environment template \meta{name}.
+\end{commands}
+Environment templates are used by the exercise and solution environments.
+Those are the templates set with the parameters \parameter{exercise-template}
+and \parameter{solution-template}.
+
+The predefined template is called \enquote{\code{default}}, see
+section~\vref{sec:exercise-templ-default}.
+
+\subsubsection{Heading Templates}\label{sec:heading-templates}
+\begin{commands}
+  \command{DeclareExerciseHeadingTemplate}[\marg{name}\marg{code}]
+    Declare the heading template \meta{name}.
+\end{commands}
+Heading templates are used by \cs{printsolutions}, \cs{printsolutionstype} and
+\cs{printcollection}.  Those are the templates set with the option
+\option{headings-template} of the modules \module{print-solutions} and
+\module{print-collection}.
+
+The predefined templates are \enquote{\code{default}},
+\enquote{\code{collection}}, \enquote{\code{per-section}} and
+\enquote{\code{per-chapter}} see section~\vref{sec:headings-templates}.
+
+\subsubsection{Grading Table Templates}\label{sec:grad-table-templ}
+\begin{commands}
+  \command{DeclareExerciseTableTemplate}[\marg{name}\marg{code}]
+    Declare the grading table template \meta{name}.
+\end{commands}
+Table templates are used by \cs{gradingtable}.  Those are the templates set
+with the option \option{template} of module \module{grading-table}
+
+The predefined templates are \enquote{\code{default}} and
+\enquote{\code{default}}, see sections~\vref{sec:table-templ-default}
+and~\vref{sec:table-templ-default*}.
+
+\subsection{Examples}\label{sec:template-examples}
+
+The repository of this package\footnote{GitHub:
+  \url{https://github.com/cgnieder/xsim/}, CTAN:
+  \url{http://www.ctan.org/pkg/xsim/}} currently includes
+\theexamplefiles~example documents demonstrating how different aspects of this
+package work or how different kinds of problems can be solved or how different
+kinds of layouts can be achieved as well as how solve concrete problems that
+have come up in different \LaTeX\ forums, see
+section~\vref{sec:example-files}.
+
+\subsubsection{The \code{default} Exercise Template}\label{sec:exercise-templ-default}
+
+Below the definition of the \code{default} exercise template provided by
+\xsim\ is shown:
+
+\begin{sourcecode}
+  \DeclareExerciseEnvironmentTemplate{default}{%
+    \subsection*
+      {%
+        \XSIMmixedcase{\GetExerciseName}\nobreakspace
+        \GetExerciseProperty{counter}%
+        \IfInsideSolutionF
+          {%
+            \GetExercisePropertyT{subtitle}
+              { {\normalfont\itshape\PropertyValue}}%
+          }%
+      }
+    \GetExercisePropertyT{points}
+      {%
+        \marginpar
+          {%
+            \IfInsideSolutionF{\rule{1.2cm}{1pt}\slash}%
+            \PropertyValue
+            \GetExercisePropertyT{bonus-points}{~(+\PropertyValue)}%
+            ~\XSIMtranslate {point-abbr}%
+          }%
+      }%
+  }
+  {}
+\end{sourcecode}
+
+\subsubsection{A New Exercise Type Using \pkg*{tcolorbox}}
+Let's say we want exercises to be put in a \env*{tcolorbox}. We want a bold
+title and. if given, an italic subtitle.  Exercises should also have the
+points after the subtitle in parentheses if given.  Let's also say we want
+those to be an additional exercise type in addition to the ones \xsim\ already
+provides.  This is shown with the following code which is also how the
+problems in this manual have been defined:
+
+\begin{sourcecode}
+  \DeclareExerciseEnvironmentTemplate{tcolorbox}
+    {%
+      \tcolorbox[
+        colback = red!5!white ,
+        colframe = red!75!black ,
+        colbacktitle = yellow!50!red ,
+        coltitle = red!25!black ,
+        breakable ,
+        drop shadow ,
+        beforeafter skip = .5\baselineskip ,
+        title =
+          \textbf{\GetExerciseName~\GetExerciseProperty{counter}}%
+          \GetExercisePropertyT{subtitle}{ \textit{\PropertyValue}}%
+          \IfInsideSolutionF{%
+            \GetExercisePropertyT{points}{ % notice the space
+              (%
+                \PropertyValue
+                \IfExerciseGoalSingularTF{points}
+                  {\XSIMtranslate{point}}
+                  {\XSIMtranslate{points}}%
+              )%
+            }%
+          }%
+      ]%
+    }
+    {\endtcolorbox}
+
+  \DeclareExerciseType{problem}{
+    exercise-env = problem ,
+    solution-env = answer ,
+    exercise-name = Problem ,
+    solution-name = Answer ,
+    exercise-template = tcolorbox ,
+    solution-template = tcolorbox
+  }
+\end{sourcecode}
+
+See it in action:
+\begin{example}
+  \begin{problem}[subtitle=My subtitle,points=5]
+    This is a problem using a subtitle and points.
+  \end{problem}
+  \begin{answer}
+    This is the answer to problem~\GetExerciseProperty{counter}.
+  \end{answer}
+\end{example}
+
+\subsubsection{Mimicking \pkg*{exsheets}' \code{runin} Template}
+
+The following example shows how you could mimick \pkg*{exsheets}' \code{runin}
+template.  The outcome isn't exactly the same since \pkg{exsheets} doesn't use
+\cs*{marginpar} but the result should look very similar.  A safer definition
+would use a real sectioning command for the title.
+
+\begin{sourcecode}
+  \usepackage{needspace}
+  \DeclareExerciseEnvironmentTemplate{runin}
+    {%
+      \par\vspace{\baselineskip}
+      \Needspace*{2\baselineskip}
+      \noindent
+      \textbf{\XSIMmixedcase{\GetExerciseName}~\GetExerciseProperty{counter}}%
+      \GetExercisePropertyT{subtitle}{ \textit{#1}} %
+      \GetExercisePropertyT{points}{%
+        \marginpar{%
+          \PropertyValue
+          \GetExercisePropertyT{bonus-points}{+\PropertyValue}%
+          \,\IfExerciseGoalSingularTF{points}
+              {\XSIMtranslate{point}}
+              {\XSIMtranslate{points}}%
+        }%
+      }%
+    }
+    {}
+\end{sourcecode}
+
+See it in action:
+\begin{example}
+  \xsimsetup{exercise/template=runin}
+  \renewcommand*\theexercise{\arabic{exercise}.}
+  \begin{exercise}[subtitle=exsheets' runin,points=2.5]
+    \lipsum[4]
+  \end{exercise}
+\end{example}
+
+\subsubsection{Mimicking \pkg*{exsheets}' \code{margin} Template}
+
+The following example shows how you could mimick \pkg*{exsheets}'
+\code{margin} template.
+
+\begin{sourcecode}
+  \usepackage{needspace}
+  \DeclareExerciseEnvironmentTemplate{margin}
+    {%
+      \par\vspace{\baselineskip}
+      \Needspace*{2\baselineskip}
+      \noindent
+      \llap{%
+        \smash{%
+          \tabular[t]{@{}r@{}}
+            \textbf{\XSIMmixedcase{\GetExerciseName}~\GetExerciseProperty{counter}}
+            \IfExercisePropertySetT{points}{%
+              \tabularnewline
+              (%
+                \GetExerciseProperty{points}%
+                \GetExercisePropertyT{bonus-points}{+#1}%
+                \,\XSIMtranslate{point-abbr}%
+              )%
+            }%
+          \endtabular
+        } % notice the space
+      }%
+    }
+    {}
+\end{sourcecode}
+
+See it in action:
+\begin{example}
+  \xsimsetup{exercise/template=margin}
+  \renewcommand*\theexercise{\arabic{exercise}.}
+  \begin{exercise}[subtitle=exsheets' margin,points=2.5]
+    \lipsum[4]
+  \end{exercise}
+\end{example}
+
+\subsubsection{The Headings Templates}\label{sec:headings-templates}
+\xsim\ defines four heading templates which only differ by which text they
+output:
+\begin{sourcecode}
+  \DeclareExerciseHeadingTemplate{default}
+    {\section*{\XSIMtranslate{default-heading}}}
+  \DeclareExerciseHeadingTemplate{collection}
+    {\section*{\XSIMtranslate{collection-heading}}}
+  \DeclareExerciseHeadingTemplate{per-section}
+    {\section*{\XSIMtranslate{per-section-heading}}}
+  \DeclareExerciseHeadingTemplate{per-chapter}
+    {\section*{\XSIMtranslate{per-chapter-heading}}}
+\end{sourcecode}
+Section~\vref{sec:exerc-transl} shows how the translations are defined.
+
+\subsubsection{The \code{default} Table Template}\label{sec:table-templ-default}
+This template is the one used for grading tables per default.  It has a
+vertical layout.
+
+\begin{sourcecode}
+  \DeclareExerciseTableTemplate{default}{%
+    \XSIMputright\ExerciseTableCode{%
+      \toprule
+      \XSIMifblankTF{\ExerciseType}
+        {}
+        {\XSIMmixedcase{\GetExerciseParameter{exercise-name}}}
+      &
+      \XSIMmixedcase{\XSIMtranslate{points}} &
+      \XSIMtranslate{reached} \\
+      \midrule
+    }%
+    \ForEachUsedExerciseByType{%
+      \XSIMifeqTF{#1}{\ExerciseTableType{#1}}
+        {%
+          \XSIMifblankTF{\ExerciseType}
+            {%
+              \XSIMputright\ExerciseTableCode{%
+                \XSIMmixedcase{\ExerciseParameterGet{#1}{exercise-name} }%
+              }%
+            }
+            {}%
+          \XSIMputright\ExerciseTableCode
+            {#3 & \XSIMifblankTF{#5}{\printgoal{0}}{\printgoal{#5}} & \\ }%
+        }
+        {}%
+    }
+    \XSIMputright\ExerciseTableCode{%
+      \midrule
+      \XSIMtranslate{total} &
+      \XSIMifblankTF{\ExerciseType}
+        {\TotalExerciseGoal{points}{}{}}
+        {\TotalExerciseTypeGoal{\ExerciseType}{points}{}{}} &
+      \\ \bottomrule
+    }%
+    \XSIMexpandcode{%
+      \noexpand\begin{tabular}{\XSIMifblankTF{\ExerciseType}{l}{c}cc}
+        \noexpand\ExerciseTableCode
+      \noexpand\end{tabular}%
+    }%
+  }
+\end{sourcecode}
+
+The part
+\begin{sourcecode}
+  \XSIMifblankTF{\ExerciseType}{ ... }{ ... }
+\end{sourcecode}
+repeatedly checks if an exercise type has been given for the table.  This
+makes it possible to design the table differently if it is for one exercise
+type only (the \code{true} case) or for all exercise types (the \code{false}
+case).  \cs*{ExerciseTableType}\marg{code} either expands to the given
+exercise type or to \meta{code}.
+
+\subsubsection{The \code{default*} Table Template}\label{sec:table-templ-default*}
+The second of the predefined grading table templates.  It has a horizontal
+layout.
+\begin{bewareofthedog}
+  If you have a lot of exercises the width of a table with this layout may
+  exceed the text width of the document!
+\end{bewareofthedog}
+
+\begin{sourcecode}
+  \DeclareExerciseTableTemplate{default*}{%
+    \XSIMputright\ExerciseTableCode{%
+      \toprule
+      \XSIMifblankTF{\ExerciseType}
+        {}
+        {\XSIMmixedcase{\GetExerciseParameter{exercise-name}}}
+        &%
+    }%
+    \ForEachUsedExerciseByType{%
+      \XSIMifeqTF {#1} { \ExerciseTableType {#1} }
+        {
+          \XSIMifblankTF{\ExerciseType}
+            {%
+              \XSIMputright\ExerciseTableCode{%
+                \XSIMmixedcase{\ExerciseParameterGet{#1}{exercise-name} }%
+              }%
+            }
+            {}%
+          \XSIMputright\ExerciseTableCode{#3 &}
+        }
+        {}%
+    }%
+    \XSIMputright\ExerciseTableCode{%
+      \XSIMtranslate{total} \\
+      \midrule
+      \XSIMmixedcase{\XSIMtranslate{points}} &
+    }%
+    \ForEachUsedExerciseByType{%
+      \XSIMifeqTF{#1}{\ExerciseTableType{#1}}
+        {%
+          \XSIMputright\ExerciseTableCode{%
+            \XSIMifblankTF{#5}{\printgoal{0}}{\printgoal{#5}} &}%
+        }
+        {}%
+    }%
+    \XSIMputright\ExerciseTableCode{%
+      \XSIMifblankTF{\ExerciseType}
+        {\TotalExerciseGoal{points}{}{}}
+        {\TotalExerciseTypeGoal{\ExerciseType}{points}{}{}}%
+      \\ \midrule
+      \XSIMtranslate{reached} &%
+    }%
+    \ForEachUsedExerciseByType{%
+      \XSIMifeqTF{#1}{\ExerciseTableType{#1}}
+        {\XSIMputright\ExerciseTableCode{&}}
+        {}%
+    }%
+    \XSIMputright\ExerciseTableCode{ \\ \bottomrule }%
+    \def\numberofcolumns{%
+      \XSIMifblankTF{\ExerciseType}
+        {\numberofusedexercises}
+        {\csname numberof \ExerciseType s\endcsname}%
+    }%
+    \XSIMifeqF{\numberofcolumns}{0}
+      {%
+        \begin{tabular}{l*{\numberofcolumns}{c}c}
+          \ExerciseTableCode
+        \end {tabular}%
+      }%
+  }
+\end{sourcecode}
+
+The part
+\begin{sourcecode}
+  \XSIMifblankTF{\ExerciseType}{ ... }{ ... }
+\end{sourcecode}
+repeatedly checks if an exercise type has been given for the table.  This
+makes it possible to design the table differently if it is for one exercise
+type only (the \code{true} case) or for all exercise types (the \code{false}
+case).  \cs*{ExerciseTableType}\marg{code} either expands to the given
+exercise type or to \meta{code}.
+
+\section{Exercise Translations}\label{sec:exerc-transl}
+
+\begin{commands}
+  \command{DeclareExerciseTranslation}[\marg{keyword}\marg{language}\marg{translation}]
+    Declare the translation of \meta{keyword} for language \meta{language}.
+  \command{DeclareExerciseTranslations}[\marg{keyword}\marg{translations}]
+    Declare the translations of \meta{keyword} for several languages at once.
+    See an example of the usage below.
+  \expandable\command{XSIMtranslate}[\marg{keyword}]
+    Delivers the translation of \meta{keyword} according to the current
+    document language (in the meaning of a \pkg{babel}~\cite{pkg:babel} or
+    \pkg{polyglossia}~\cite{pkg:polyglossia} language).
+  \command{ForEachExerciseTranslation}[\marg{code}]
+    Loops over all translations of all keywords known to \xsim.  Inside
+    \meta{code} you can refer to the keyword with \code{\#1}, to the language
+    with \code{\#2}, and to the translation with \code{\#3}.
+\end{commands}
+
+As an example how to use \cs{DeclareExerciseTranslations} here is how the
+translations for \code{exercise} have been defined:
+
+\begin{sourcecode}
+  \DeclareExerciseTranslations{exercise}{
+    Fallback = exercise ,
+    English  = exercise ,
+    French   = exercice ,
+    German   = \"Ubung
+  }
+\end{sourcecode}
+
+Table~\vref{tab:translation-keys} shows all existing keywords with all
+predefined translations.
+
+\ForEachExerciseTranslation{
+  \appto\translationtable{\texttt{#1} & #2 & \texttt{\detokenize{#3}} \\}
+}
+
+\begin{longtable}{llp{.55\linewidth}}
+    \caption{Translation keywords predefined by \xsim.}
+    \label{tab:translation-keys} \\
+    \toprule
+    \bfseries keyword & \bfseries language & \bfseries translation \\
+    \midrule
+  \endfirsthead
+    \toprule
+    \bfseries keyword & \bfseries language & \bfseries translation \\
+    \midrule
+  \endhead
+    \bottomrule
+  \endlastfoot
+    \midrule
+    & & \hfill\emph{continues} \\
+  \endfoot
+    \translationtable
+\end{longtable}
+
+\section{Cloze Tests and Blank Lines}
+
+Similar to \pkg{exsheets} \xsim\ provides a command \cs{blank}:
+\begin{commands}
+  \command{blank}[\sarg\oarg{options}\marg{text to be filled in}]
+    Creates a blank in normal text or in an exercise but fills the text of its
+    argument if inside a solution.  If used at the \emph{begin of a paragraph}
+    \cs{blank} will do two things: it will set the linespread according to an
+    option explained below and will insert \cs*{par} after the lines.  The
+    starred version doesn't do these things.
+\end{commands}
+
+Those are the options for customization:
+\begin{options}
+  \keyval{blank-style}{code}\Module{blank}\Default{\cs*{underline}\Marg{\#1}}
+    Instructions for typesetting the blank cloze.  Refer to the filled in
+    space with \code{\#1}.
+  \keyval{filled-style}{code}\Module{blank}\Default{\cs*{underline}\Marg{\#1}}
+    Instructions for typesetting the filled cloze.  Refer to the filled in text
+    with \code{\#1}
+  \keyval{style}{code}
+    Shortcut for setting both \option{blank-style} and \option{filled-style}
+    at once.
+  \keyval{scale}{decimal number}\Module{blank}\Default{\code{1}}
+\textsc{}    Scales the blank to \meta{decimal number} times its natural width.
+  \keyval{width}{dim}\Module{blank}\Default
+    Sets the blank to a width of \meta{dim}.  This takes precendence over
+    \option{scale}.
+  \keyval{linespread}{decimal number}\Module{blank}\Default{\code{1}}
+    Set the linespread for the blank lines. This only has an effect if
+    \cs{blank} is used at the begin of a paragraph.
+  \keyval{line-increment}{dim}\Module{blank}\Default{\code{1pt}}
+    The blank line is built in multiples of this value.  If the value is too
+    large you may end up with uneven lines.  If the value is too small you may
+    end up with a non-ending compilation.  Experiment with values to find the
+    suiting one for your use case.
+  \keyval{line-minimum-length}{dim}\Module{blank}\Default{\code{2em}}
+     The minimal length a line must have before it is built step by step.
+\end{options}
+
+\begin{example}
+  This is a \blank{blank} outside in normal text.
+  \begin{exercise}
+    Try to fill in \blank[width=4cm]{these} blanks.  All of them
+    \blank{are created} by using the \cs{blank} \blank{command}.
+  \end{exercise}
+  \xsimsetup{blank/filled-style=\textcolor{red}{#1}}
+  \begin{solution}[print]
+    Try to fill in \blank[width=4cm]{these} blanks.  All of them
+    \blank{are created} by using the \cs{blank} \blank{command}.
+  \end{solution}
+\end{example}
+A number of empty lines are easily created by setting the \option{width}
+option:
+\begin{example}
+  Write up the pros and cons of \xsim\ over \pkg{exsheets}:
+  
+  \blank[width=4.8\linewidth,linespread=1.5]{}
+\end{example}
+
+\edef\lastsection{\arabic{section}}
+
+\appendix
+
+\section{Future Plans}
+
+\xsim\ is complete in so far as it is perfectly usable to create exams or
+exercise and solution sections in books with the most freedom in layout
+already.  But still there are features which would be useful additions.  Below
+I list all ideas that I currently plan to add to \xsim:
+\begin{itemize}
+  \item a document class \code{xsim-exam} for creating exams; this class
+    should itself feature the possibility of creating different versions of an
+    exam, maybe already provide multiple choice questions and so on; one could
+    also think about automatic creation of running headers and footers, \ie,
+    means for changing the layout of the exam; following the spirit of \xsim\
+    this should probably be done using templates as well.
+\end{itemize}
+I am very open to suggestions regarding features, both in general and
+specifically regarding the document class.
+
+\section{FAQ \& How to\dots}
+This section serves as a kind of gallery showing solutions to common
+problems.  I expect this section to grow over the years.  Some examples
+especially regarding other layouts are also shown in example files added to
+this package.
+
+\subsection{\dots Know if \xsim\ Needs Another Compilation?}
+If \xsim\ wants you to recompile your document it writes the following to the
+logfile:
+\begin{sourcecode}
+  *************************************************
+  * xsim warning: "rerun"
+  * 
+  * Exercise properties may have changed. Rerun to get them synchronized.
+  *************************************************
+\end{sourcecode}
+So just check the logfile regularly (which you should be doing anyway) and
+keep your eyes open.
+
+\subsection{\dots Resolve Getting Repeatedly Wrong Exercise Properties or
+  Wrong Exercise Lists?}\label{sec:resolve-getting}
+\xsim\ writes a lot of stuff to the auxfile for re-using information on
+subsequent compilations.  If you add exercises, change properties \etc\ it
+might happen that wrong information is staying in the auxfile and is wrongly
+used by \xsim.  In such cases deleting the auxfile and doing a few fresh
+compilations may resolve your problems.
+
+Sometimes the \emph{existence of exercise or solution files from earlier
+  compilations} may lead to wrong lists of exercises or solutions.  In such
+cases it can be useful to delete all those files and doing a fresh
+compilation.  It may be helpful to use a subfolder for those exernal files
+which will make deleting them a little bit easier. (Don't forget to both
+create the subfolder and set \option{path} accordingly then.)
+
+Using the \option{clear-aux} option might help to reduce erroneous exercises.
+
+\subsection{\dots Resolve Strange Errors After Updating?}
+\xsim\ writes a lot of stuff to the auxfile.  An update may well change how
+this is done so deleting the auxfile and doing a few fresh compilations may
+resolve your problems.
+
+\subsection{\code{! TeX capacity exceeded, sorry [text input levels=15].}
+  Why?}
+Did you try to use an exercise or solution in a macro of some sort?  This
+generally will fail\footnote{The reasons are not entirely clear to me.}.  But
+there should never be the need to hide the environments inside of a macro,
+anyway.
+
+\subsection{\code{Runaway argument? !File ended while scanning use of \^\^M.} Why?}
+Did you try to use an exercise or solution in a macro of some sort?  This
+generally will fail.  But there should never be the need to hide the
+environments inside of a macro, anyway.
+
+\subsection{\dots Put a Star (or Another Symbol) in Headings of Exercises That
+  Are Special?}
+
+The code below shows one possible modification of an exercise template which
+allows to easily create bonus exercises:
+\begin{sourcecode}
+  % preamble:
+  \usepackage{amsymb}
+  % declare boolean property:
+  \DeclareExerciseProperty*{bonus}
+  \DeclareExerciseEnvironmentTemplate{bonus}
+    {%
+      \subsection*
+        {%
+          % test for boolean property and insert star symbol if true:
+          \IfExerciseBooleanPropertyT{bonus}{\llap{$\bigstar$ }Bonus }%
+          \XSIMmixedcase{\GetExerciseName}\nobreakspace
+          \GetExerciseProperty{counter}%
+          \IfInsideSolutionF
+            {%
+              \IfExercisePropertySetT{subtitle}
+                { {\normalfont\itshape\GetExerciseProperty{subtitle}}}%
+            }%
+        }
+      \GetExercisePropertyT{points}
+        {%
+          \marginpar
+            {%
+              \IfInsideSolutionF{\rule{1.2cm}{1pt}\slash}%
+              \PropertyValue
+              \GetExercisePropertyT{bonus-points}
+                {\nobreakspace(+\PropertyValue)}%
+              \nobreakspace\XSIMtranslate{point-abbr}%
+            }%
+        }%
+    }
+    {}
+\end{sourcecode}
+
+The usage is now as follows:
+\begin{example}
+  \xsimsetup{exercise/template = bonus}
+  % set the boolean property to true
+  \begin{exercise}[bonus]
+    A bonus question.
+  \end{exercise}
+\end{example}
+
+\subsection{\dots Create and Use \xsim\ Style Files?}
+
+\xsim\ offers you the possibility to create own \emph{style files}.  Let's say
+you want to have a style called \code{math-exam}.  Then you need to save all
+necessary definitions in a file called:
+\begin{center}
+  \code{xsim.math-exam.code.tex}
+\end{center}
+The first command in the file should be \cs{xsimstyle}\Marg{math-exam}.  This
+file can now be loaded into your document using
+\cs{loadxsimstyle}\Marg{math-exam}:
+\begin{sourcecode}
+  \documentclass[DIV=18,parskip=half]{scrartcl}
+  \usepackage[T1]{fontenc}
+  \usepackage[utf8]{inputenc}
+
+  \usepackage[clear-aux]{xsim}
+  \loadxsimstyle{math-exam}
+
+  \title{Math Exam \#3}
+  \date{2017-03-28}
+\end{sourcecode}
+
+In this style file stuff like template and property definitions should
+happen.  This is more or less a convenient way to
+\begin{itemize}
+  \item keep the preamble \enquote{clean} and
+  \item define re-usable styles without the need of copying the document
+    preamble to another document.
+\end{itemize}
+A style file is like a package or class file, \ie, \code{@} has category
+code~11 (letter).
+
+The formal description of the commands:
+\begin{commands}
+  \command{xsimstyle}[\sarg\marg{style name}]
+    The first command in a \xsim\ style file called \code{xsim.\meta{style
+        name}.code.tex} which defines the \xsim\ style \meta{style name}.  The
+    starred version activates expl3 syntax\footnote{Those users who want this
+      will know what it means.  If you don't know what it means you will not
+      need it.}.
+  \command{loadxsimstyle}[\marg{csv list of style names}]
+    Load one or more styles into the document.
+\end{commands}
+
+\begin{bewareofthedog}
+  At the moment this mechanism offers no advantages over creating a custom
+  package or simply \cs*{input}ing a file.  Future versions might provide
+  additional features.
+\end{bewareofthedog}
+
+\subsection{\dots Print All Solutions Grouped by Section?}
+Here is an idea how to get a list of all solutions grouped by the section the
+corresponding exercises are appearing in.
+\begin{sourcecode}
+  % preamble:
+  % \usepackage{etoolbox}
+  % \newcounter{sections}
+
+  % document:
+  \setcounter{sections}{1}
+  \whileboolexpr
+    { test {\ifnumless{\value{sections}}{\value{section}+1}} }
+    {
+      \printsolutions[section=\value{sections},headings-template=per-section]
+      \stepcounter{sections}
+    }
+\end{sourcecode}
+For this manual we then get the following list\footnote{Taking care of the
+  fact that we're in the appendix now which means we can't use
+  \cs*{value}\Marg{section}.  Therefore this manual does
+  \cs*{edef}\cs*{lastsection}\Marg{\cs*{arabic}\Marg{section}} right before
+  \cs*{appendix}}.
+
+\newcounter{sections}
+\setcounter{sections}{1}
+\whileboolexpr
+  { test {\ifnumless{\value{sections}}{\lastsection+1}} }
+  {
+    \printsolutions[section=\value{sections},headings-template=per-section]
+    \stepcounter{sections}
+  }
+    
+\section{The \pkg*{xsimverb} package}\label{sec:xsimverb-package}
+\xsim\ comes bundled with another package called \pkg{xsimverb}.  This package
+loads a very small subset of \xsim\ which allows to create environments which
+write their contents verbatim to external files.  It provides the following
+commands (which of course are also available in \xsim, too):
+
+\begin{commands}
+  \command{XSIMfilewritestart}[\sarg\marg{file name}]
+    Start writing to the file named \meta{file name}.  This should be the
+    \emph{last} command in the \emph{begin} definition of an environment.  If
+    is is used in an environment with arguments where the \emph{last} argument
+    is optional you should check if the optional argument is given and use
+    the starred version if the test is negative.  This is demonstrated in an
+    example below using \pkg{xparse}'s \cs{NewDocumentEnvironment}.  \emph{If
+      you want an environment with only an optional argument you \emph{should}
+      use \pkg{xparse}'s commands to define it.  Due to the way how
+      \cs*{newenvironment} scans for optional arguments you'll otherwise may
+      end up with leading spaces gobbled from the first line in your
+      environment.}
+  \command{XSIMfilewritestop}
+    Stop writing to the file.  This should be the \emph{first} command in the
+    \emph{end} definition of an environment.
+  \command{XSIMsetfilebegin}[\marg{code}]
+    This command can be used to write something to the external file
+    \emph{before} the environment contents.  Must be set before
+    \cs{XSIMfilewritestart} in the \emph{begin} definition.
+  \command{XSIMsetfileend}[\marg{code}]
+    This command can be used to write something to the external file
+    \emph{after} the environment contents.  Must be set before
+    \cs{XSIMfilewritestart} in the \emph{begin} definition.
+  \command{XSIMgobblechars}[\marg{integer}]
+    Determines how many characters are cut off of the beginning of each line
+    of the environment body before it is written to the file.  The default
+    value is~$0$.
+\end{commands}
+
+An example of how to use those commands:
+\begin{sourcecode}
+  \documentclass{article}
+  \usepackage{xsimverb,listings}
+
+  \makeatletter
+  \NewDocumentEnvironment{example}{o}
+    {%
+      \XSIMsetfilebegin{\@percentchar\space file `\jobname.tmp'}%
+      \XSIMsetfileend{\@percentchar\space bye bye}%
+      \IfNoValueTF{#1}
+        {\XSIMfilewritestart*{\jobname.tmp}}
+        {\XSIMfilewritestart{\jobname.tmp}}%
+    }
+    {%
+      \XSIMfilewritestop
+      \lstinputlisting[language={[LaTeX]TeX}]{\jobname.tmp}%
+      \input{\jobname.tmp}
+    }
+  \makeatother
+
+  \begin{document}
+  
+  \begin{example}
+  bla bla \LaTeX
+  \end{example}
+
+  \end{document}
+\end{sourcecode}
+
+The \code{tmp} file produced by the above example will contain the following
+three lines (if the file itself was called \code{test.tex}):
+\begin{sourcecode}
+  % file `test.tmp'
+  bla bla \LaTeX
+  % bye bye
+\end{sourcecode}
+
+\section{All Exercise Examples}
+
+\begin{bewareofthedog}
+  You will notice that some exercises from
+  section~\vref{sec:template-examples} look differently in this section.  That
+  is because all exercises of a type use the template that's \emph{currently
+    active}.  If you want exercises with a different look you should use
+  different exercises types.
+\end{bewareofthedog}
+
+The following list is created with this code:
+\begin{sourcecode}
+  \xsimsetup{exercise/template = bonus}
+  \printcollection[headings]{all exercises}
+\end{sourcecode}
+
+\xsimsetup{exercise/template = bonus}
+\printcollection[headings]{all exercises}
+
+\section{All Solution Examples}
+\printsolutions
+
+\section{Example Documents Coming With This Package}\label{sec:example-files}
+The repository of this package\footnote{GitHub:
+  \url{https://github.com/cgnieder/xsim/}, CTAN:
+  \url{http://www.ctan.org/pkg/xsim/}} currently includes
+\theexamplefiles~example documents demonstrating how different aspects of this
+package work or how different kinds of problems can be solved or how different
+kinds of layouts can be achieved as well as how solve concrete problems that
+have come up in different \LaTeX\ forums.
+
+\listexamplefiles
+
+\printbibliography
+
+\end{document}
diff --git a/Master/texmf-dist/tex/latex/xsim/xsim-manual.cls b/Master/texmf-dist/tex/latex/xsim/xsim-manual.cls
new file mode 100644
index 00000000000..56121054dd8
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/xsim/xsim-manual.cls
@@ -0,0 +1,755 @@
+% ----------------------------------------------------------------------------
+% the XSIM package
+% 
+%   eXercise Sheets IMproved
+% 
+% ----------------------------------------------------------------------------
+% Clemens Niederberger
+% Web:    https://github.com/cgnieder/xsim
+% E-Mail: contact@mychemistry.eu
+% ----------------------------------------------------------------------------
+% Copyright 2017 Clemens Niederberger
+% 
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+% 
+% This work has the LPPL maintenance status `maintained'.
+% 
+% The Current Maintainer of this work is Clemens Niederberger.
+% ----------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% ----------------------------------------------------------------------------
+%
+% please ignore the contents of this file -- it is not a good example for
+% coding...
+%
+\ProvidesClass{xsim-manual}[2017/04/14]
+
+\LoadClass[load-preamble,add-index]{cnltx-doc}
+\RequirePackage{imakeidx}
+\RequirePackage[utf8]{inputenc}
+\RequirePackage{xsim}
+
+\RequirePackage{geometry}
+\geometry{
+  left = 3.8cm ,
+  right = 2.8cm
+}
+
+\setcnltx{
+  package  = {xsim},
+  info     =
+    \textsc{e\textcolor{cnltx}{X}ercise \textcolor{cnltx}{S}heets
+    \textcolor{cnltx}{IM}proved} \\
+    the official successor of the \cnltxpackagenameformat{exsheets} package ,
+  url      = https://github.com/cgnieder/xsim ,
+  authors  = Clemens Niederberger ,
+  email    = contact@mychemistry.eu ,
+  quote-format = \small\biolinumLF ,
+  add-cmds = {
+    blank ,
+    addbonus ,
+    addpoints ,
+    AddtoExerciseGoal ,
+    AddtoExerciseGoalPrint ,
+    AddtoExerciseTypeGoal ,
+    AddtoExerciseTypeGoalPrint ,
+    blank ,
+    collectexercises ,
+    collectexercisestype ,
+    collectexercisesstop ,
+    DeclareExerciseCollection ,
+    DeclareExerciseEnvironmentTemplate ,
+    DeclareExerciseGoal ,
+    DeclareExerciseHeadingTemplate ,
+    DeclareExerciseProperty ,
+    DeclareExercisePropertyAlias ,
+    DeclareExerciseTableTemplate ,
+    DeclareExerciseTagging ,
+    DeclareExerciseTranslation ,
+    DeclareExerciseTranslations ,
+    DeclareExerciseType ,
+    DeclareGradeDistribution ,
+    ExerciseCollection ,
+    ExerciseGoalValuePrint ,
+    ExerciseID ,
+    ExerciseParameterGet ,
+    ExercisePropertyGet ,
+    ExercisePropertyGetAlias ,
+    ExercisePropertyGlobalSave ,
+    ExercisePropertyIfSetF ,
+    ExercisePropertyIfSetT ,
+    ExercisePropertyIfSetTF ,
+    ExercisePropertySave ,
+    ExerciseTableType ,
+    ExerciseTableCode ,
+    ExerciseType ,
+    ForeachExerciseTag ,
+    ForEachExerciseTranslation ,
+    ForEachPrintedExerciseByType ,
+    ForEachPrintedExerciseByID ,
+    ForEachUsedExerciseByType ,
+    ForEachUsedExerciseByID ,
+    GetExerciseAliasProperty ,
+    GetExerciseName ,
+    GetExerciseParameter ,
+    GetExerciseProperty ,
+    GetExercisePropertyF ,
+    GetExercisePropertyT ,
+    GetExercisePropertyTF ,
+    GlobalSaveExerciseProperty ,
+    gradingtable ,
+    IfExerciseBooleanPropertyF ,
+    IfExerciseBooleanPropertyT ,
+    IfExerciseBooleanPropertyTF ,
+    IfExerciseGoalF ,
+    IfExerciseGoalF ,
+    IfExerciseGoalTF ,
+    IfExerciseGoalSingularF ,
+    IfExerciseGoalSingularT ,
+    IfExerciseGoalSingularTF ,
+    IfExerciseGoalsSumF ,
+    IfExerciseGoalsSumT ,
+    IfExerciseGoalsSumTF ,
+    IfExercisePropertyExistF ,
+    IfExercisePropertyExistT ,
+    IfExercisePropertyExistTF ,
+    IfExercisePropertySetF ,
+    IfExercisePropertySetT ,
+    IfExercisePropertySetTF ,
+    IfExerciseTypeGoalsSumF ,
+    IfExerciseTypeGoalsSumT ,
+    IfExerciseTypeGoalsSumTF ,
+    IfInsideSolutionF ,
+    IfInsideSolutionT ,
+    IfInsideSolutionTF ,
+    loadxsimstyle ,
+    numberofexercises ,
+    numberofusedexercises ,
+    points ,
+    printallsolutions ,
+    printcollection ,
+    printexercise ,
+    printgoal ,
+    printpoints ,
+    printrandomexercises ,
+    printsolution ,
+    printsolutions ,
+    printsolutionstype ,
+    PropertyValue ,
+    SaveExerciseProperty ,
+    SetExerciseParameter ,
+    SetExerciseParameters ,
+    theexercise ,
+    TotalExerciseGoal ,
+    TotalExerciseGoals ,
+    TotalExerciseTypeGoal ,
+    TotalExerciseTypeGoals ,
+    UseExerciseTags ,
+    UseExerciseTagsX ,
+    UseExerciseTemplate ,
+    XSIMexpandcode ,
+    XSIMsetfilebegin ,
+    XSIMfilewritestart ,
+    XSIMfilewritestop ,
+    XSIMgobblechars ,
+    XSIMsetfileend ,
+    XSIMifblankT ,
+    XSIMifblankF ,
+    XSIMifblankTF ,
+    XSIMifchapterF ,
+    XSIMifchapterT ,
+    XSIMifchapterTF ,
+    XSIMifeqF ,
+    XSIMifeqT ,
+    XSIMifeqTF ,
+    XSIMmixedcase ,
+    XSIMputright ,
+    xsimsetup ,
+    xsimstyle ,
+    XSIMtranslate
+  } ,
+  add-envs = { exercise , solution } ,
+  add-silent-cmds = {
+    @percentchar ,
+    bottomrule ,
+    breite ,
+    choice ,
+    cs ,
+    DeclareFloatingEnvironment ,
+    enddescription ,
+    endtcolorbox ,
+    hoehe ,
+    iflist ,
+    IfNoValueTF ,
+    ifnumless ,
+    lipsum ,
+    lstdefinestyle ,
+    lstset ,
+    midrule ,
+    Needspace ,
+    NewDocumentCommand ,
+    NewDocumentEnvironment ,
+    newlist ,
+    numberofcolumns ,
+    numberofproblems ,
+    pkg ,
+    pointsandbonus ,
+    printA, printC, printE ,
+    printcompletepoints ,
+    printsumofpointsandbonus ,
+    setlist ,
+    settasks ,
+    tcbuselibrary ,
+    tcolorbox ,
+    thesection ,
+    toprule ,
+    whileboolexpr ,
+    xsim
+  } ,
+  pre-output = { \let\marginpar\marginnote } ,
+  add-listings-options = {
+    numberstyle = \tiny\noncopy
+  } ,
+  index-setup = { level = \section } ,
+  makeindex-setup = { columns = 2 , columnsep = 1em } ,
+  module-sep = {\texttt{/}}%
+}
+
+\renewcommand*\cnltx@module@text[2]{%
+  \begingroup
+    \reversemarginpar
+    \setlength\marginparsep{1em}%
+    \marginnote{\hfill\llap{\module#1{#2}\cnltx@module@sep}}%
+  \endgroup
+}
+
+\RequirePackage{accsupp}
+\newcommand*\noncopy[1]{%
+  \BeginAccSupp{method=escape,ActualText={}}%
+    #1%
+  \EndAccSupp{}%
+}
+
+\def\libertine@figurestyle{LF}
+\RequirePackage[libertine]{newtxmath}
+\def\libertine@figurestyle{OsF}
+
+\RequirePackage{refcount}
+
+\renewcommand*\footref[1]{%
+  \begingroup
+    \unrestored@protected@xdef\@thefnmark{\getrefnumber{#1}}%
+  \endgroup
+  \@footnotemark
+}
+
+\newcommand*\eTeX{%
+  \texorpdfstring
+    {\mbox{$\epsilon$-\TeX}}
+    {e-TeX}%
+}
+
+\RequirePackage[
+  backend=biber,
+  style=cnltx,
+  sortlocale=en_US,
+  indexing=cite]{biblatex}
+\addbibresource{cnltx.bib}
+
+\RequirePackage[biblatex]{embrac}
+\ChangeEmph{[}[,.02em]{]}[.055em,-.08em]
+\ChangeEmph{(}[-.01em,.04em]{)}[.04em,-.05em]
+
+\defbibheading{bibliography}{\section{References}}
+
+\colorlet{property}{orange}
+\newidxcmd\property{\code{\textcolor{property}{#1}}}[ (property)]
+\newrobustcmd*\prop{\@ifstar{\cnltx@prop@star}{\cnltx@prop@nostar}}
+
+\RequirePackage{marginnote}
+
+\renewcommand*\module@idx@app{ (option class)}
+
+\newrobustcmd*\cnltx@prop@star{%
+  \cnltx@ifdash
+    {\cnltx@prop@aux*\meta}
+    {\cnltx@prop@aux*\marg}%
+}
+\newrobustcmd*\cnltx@prop@nostar{%
+  \cnltx@ifdash
+    {\cnltx@prop@aux{}\meta}
+    {\cnltx@prop@aux{}\marg}%
+}
+\newcommand*\cnltx@prop@aux[4]{%
+  \code{\property#1{#3}\cnltx@isvalue#2{#4}}%
+}
+
+\newrobustcmd*\propis{%
+  \@ifstar
+    {\cnltx@propis*}
+    {\cnltx@propis{}}%
+}
+\newrobustcmd*\cnltx@propis[1]{%
+  \cnltx@ifdash
+    {\cnltx@prop@aux{#1}\@firstofone}
+    {\cnltx@prop@aux{#1}\Marg}%
+}
+\newrobustcmd*\choiceprop{%
+  \@ifstar
+    {\cnltx@choiceprop@star}
+    {\cnltx@choiceprop@nostar}%
+}
+\def\cnltx@choiceprop@star#1#2{%
+  \code{\property*{#1}\cnltx@isvalue\choices{#2}}}
+\def\cnltx@choiceprop@nostar#1#2{%
+  \code{\property{#1}\cnltx@isvalue\choices{#2}}}
+\newcommand*\boolprop{%
+  \@ifstar
+    {\cnltx@boolprop@star}
+    {\cnltx@boolprop@nostar}%
+}
+\def\cnltx@boolprop@star#1{\choiceprop*{#1}{\default{true},false}}
+\def\cnltx@boolprop@nostar#1{\choiceprop{#1}{\default{true},false}}
+
+\newenvironment{properties}
+  {%
+    \def\propert{\@cnltx@option@item\property}%
+    \def\propval{\@cnltx@option@item\prop}%
+    \def\proplit{\@cnltx@option@item\propis}%
+    \def\propchoice{\@cnltx@option@item\choiceprop}%
+    \def\propbool{\@cnltx@option@item\boolprop}%
+    \cnltxlist
+  }
+  {\endcnltxlist}
+
+\colorlet{parameter}{blue}
+\newidxcmd\parameter{\code{\textcolor{parameter}{#1}}}[ (parameter)]
+\newrobustcmd*\para{\@ifstar{\cnltx@para@star}{\cnltx@para@nostar}}
+
+\newrobustcmd*\cnltx@para@star{%
+  \cnltx@ifdash
+    {\cnltx@para@aux*\meta}
+    {\cnltx@para@aux*\marg}%
+}
+\newrobustcmd*\cnltx@para@nostar{%
+  \cnltx@ifdash
+    {\cnltx@para@aux{}\meta}
+    {\cnltx@para@aux{}\marg}%
+}
+\newcommand*\cnltx@para@aux[4]{%
+  \code{\parameter#1{#3}\cnltx@isvalue#2{#4}}%
+}
+
+\newrobustcmd*\parais{%
+  \@ifstar
+    {\cnltx@parais*}
+    {\cnltx@parais{}}%
+}
+\newrobustcmd*\cnltx@parais[1]{%
+  \cnltx@ifdash
+    {\cnltx@para@aux{#1}\@firstofone}
+    {\cnltx@para@aux{#1}\Marg}%
+}
+\newrobustcmd*\choicepara{%
+  \@ifstar
+    {\cnltx@choicepara@star}
+    {\cnltx@choicepara@nostar}%
+}
+\def\cnltx@choicepara@star#1#2{%
+  \code{\parameter*{#1}\cnltx@isvalue\choices{#2}}}
+\def\cnltx@choicepara@nostar#1#2{%
+  \code{\parameter{#1}\cnltx@isvalue\choices{#2}}}
+\newcommand*\boolpara{%
+  \@ifstar
+    {\cnltx@boolpara@star}
+    {\cnltx@boolpara@nostar}%
+}
+\def\cnltx@boolpara@star#1{\choicepara*{#1}{\default{true},false}}
+\def\cnltx@boolpara@nostar#1{\choicepara{#1}{\default{true},false}}
+
+\newenvironment{parameters}
+  {%
+    \def\param{\@cnltx@option@item\parameter}%
+    \def\paraval{\@cnltx@option@item\para}%
+    \def\paralit{\@cnltx@option@item\parais}%
+    \def\parachoice{\@cnltx@option@item\choicepara}%
+    \def\parabool{\@cnltx@option@item\boolpara}%
+    \cnltxlist
+  }
+  {\endcnltxlist}
+
+\RequirePackage{acro}
+
+\DeclareAcronym{prop}{
+  short = property ,
+  long  = \emph{Properties} are options of exercises which are individual for
+    each exercise and can be retrieved and used in exercise templates. ,
+  short-plural-form = properties
+}
+
+\DeclareAcronym{para}{
+  short = parameter ,
+  long  = \emph{Parameters} are options of exercise types which are the same
+    for each exercise of a type and can be retrieved and used in exercise
+    templates.
+}
+
+\DeclareAcronym{goal}{
+  short = goal ,
+  long  = \emph{Goals} are a certain type of \acsp*{prop} with a numerical
+    value the sum of which is available throughout the document.
+}
+
+\DeclareAcronym{tag}{
+  short = tag ,
+  long  = \emph{Tags} are a certain type of \acsp*{prop} with a csv list as
+    value which can be used for selective usage of exercises.
+}
+
+\DeclareAcronym{coll}{
+  short = collection ,
+  long  = A \emph{collection} bundles a number of exercises of one type or all
+    types of exercises within certain barriers in the document.  Those
+    exercise collections can be printed at any place in the document.
+}
+
+\DeclareAcronym{tmpl}{
+  short = template ,
+  long  = {\emph{Templates} are generic code frameworks which are used for
+    typesetting \xsim's objects such as exercises, solutions, or grading
+    tables.}
+}
+
+\ExplSyntaxOn
+\NewAcroCommand \Acs
+  {
+    \acro_first_upper:
+    \acro_short:n {#1}
+  }
+\NewAcroCommand \Acsp
+  {
+    \acro_first_upper:
+    \acro_plural:
+    \acro_short:n {#1}
+  }
+\ExplSyntaxOff
+
+\newcommand*\environ{\@ifstar\environ@star\environ@nostar}
+\newcommand*\environ@star[1]{\beginenv*\Marg{\env*{#1}}}
+\newcommand*\environ@nostar[1]{\beginenv*\Marg{\env{#1}}}
+
+\RequirePackage{tcolorbox}
+\tcbuselibrary{skins,breakable}
+\tcbset{enhanced,enhanced jigsaw}
+
+\newtcolorbox{bewareofthedog}{
+  colback  = white ,
+  colframe = red ,
+  underlay={%
+    \path[draw=none]
+      (interior.south west)
+      rectangle node[red]{\Huge\bfseries !}
+      ([xshift=-4mm]interior.north west);
+    }%
+}
+
+\newtcolorbox{cnltxcode}[1][]{
+  boxrule = 1pt ,
+  colback = cnltxbg ,
+  colframe = cnltx ,
+  arc = 5pt ,
+  beforeafter skip = .5\baselineskip ,%
+  #1%
+}
+
+\RenewDocumentEnvironment{sourcecode}{O{}}
+  {%
+    \pgfqkeys{/cnltx}{#1}%
+    \setlength\cnltx@sidebysidewidth
+      {\dimexpr .45\columnwidth -\lst@xleftmargin -\lst@xrightmargin\relax}%
+    \XSIMexpandcode{%
+      \noexpand\lstset{
+        style=cnltx,
+        \ifboolexpe{ bool {cnltx@sidebyside} and not bool {cnltx@codeonly} }
+          {linewidth=\cnltx@sidebysidewidth,}{}%
+        \expandonce\cnltx@local@listings@options
+      }%
+    }%
+    \XSIMgobblechars{2}%
+    \XSIMifblankTF{#1}
+      {\XSIMfilewritestart*{\jobname.tmp}}
+      {\XSIMfilewritestart{\jobname.tmp}}%
+  }
+  {%
+    \XSIMfilewritestop
+    \cnltxcode[breakable]%
+    \lstinputlisting[style=cnltx]{\jobname.tmp}%
+    \endcnltxcode
+  }
+
+\RenewDocumentEnvironment{example} {O{}}
+  {%
+    \pgfqkeys{/cnltx}{#1}%
+    \setlength\cnltx@sidebysidewidth
+      {\dimexpr .45\columnwidth -\lst@xleftmargin -\lst@xrightmargin\relax}%
+    \XSIMexpandcode{%
+      \noexpand\lstset{
+        style=cnltx,
+        \ifboolexpe{ bool {cnltx@sidebyside} and not bool {cnltx@codeonly} }
+          {linewidth=\cnltx@sidebysidewidth,}{}%
+        \expandonce\cnltx@local@listings@options
+      }%
+    }%
+    \XSIMgobblechars{2}%
+    \XSIMifblankTF{#1}
+      {\XSIMfilewritestart*{\jobname.tmp}}
+      {\XSIMfilewritestart{\jobname.tmp}}%
+  }
+  {%
+    \XSIMfilewritestop
+    \ifbool{cnltx@sidebyside}
+      {%
+        \cnltxcode
+        \noindent
+        \minipage[c]{\cnltx@sidebysidewidth}%
+          \cnltx@pre@source@hook
+          \lstinputlisting[style=cnltx] {\jobname.tmp}%
+          \cnltx@after@source@hook
+        \endminipage\hfill
+        \minipage[c]{\cnltx@sidebysidewidth}%
+          \cnltx@pre@example@hook
+          \input {\jobname.tmp}%
+          \cnltx@after@example@hook
+        \endminipage
+      }
+      {%
+        \cnltxcode[breakable]%
+        \cnltx@pre@source@hook
+        \lstinputlisting{\jobname.tmp}%
+        \cnltx@after@source@hook
+        \tcblower
+        \cnltx@pre@example@hook
+        \input {\jobname.tmp}%
+        \cnltx@after@example@hook
+      }%
+    \endcnltxcode
+  }
+
+\renewrobustcmd*\inputsourcecode[2][]{%
+  \begingroup
+    \pgfqkeys{/cnltx}{#1}%
+    \XSIMexpandcode{%
+      \noexpand\lstset{
+        style=cnltx,%
+        \expandonce\cnltx@local@listings@options
+      }%
+    }%
+    \cnltxcode[breakable]%
+      \lstinputlisting{#2}%
+    \endcnltxcode
+  \endgroup
+}
+
+\RequirePackage{longtable,booktabs}
+
+\RequirePackage{lipsum}
+\RequirePackage{varioref}
+\RequirePackage{bookmark}
+
+\xsimsetup{
+  clear-aux ,
+  path = exercises
+}
+
+\DeclareExerciseCollection{foo}
+
+\newrobustcmd*\TF{%
+  \colorlet{outside}{.}%
+  \textcolor{red}{\underline{\textcolor{outside}{TF}}}%
+}
+
+\newcommand*\narg{\textcolor{argument}{\code{-}}}
+\newcommand*\barg{\textcolor{argument}{\code{\bang}}}
+
+\newrobustcmd\bang{!}
+
+\renewrobustcmd*\code[1]{\begingroup\codefont\let\^\textasciicircum#1\endgroup}
+
+\DeclareExerciseEnvironmentTemplate{tcolorbox}
+  {%
+    \tcolorbox[
+      colback = red!5!white ,
+      colframe = red!75!black ,
+      colbacktitle = yellow!50!red ,
+      coltitle = red!25!black ,
+      subtitle style = {
+        boxrule = 0.4pt ,
+        colback = yellow!50!red!25!white
+      } ,
+      breakable ,
+      drop shadow ,
+      beforeafter skip = .5\baselineskip ,
+      title =
+        \textbf{\GetExerciseName~\GetExerciseProperty{counter}}%
+        \GetExercisePropertyT{subtitle}
+          { \textit{\PropertyValue}}%
+        \IfInsideSolutionF{%
+          \GetExercisePropertyT{points}
+            { % notice the space
+              (\PropertyValue
+              \IfExerciseGoalSingularTF{points}
+                {\XSIMtranslate{point}}
+                {\XSIMtranslate{points}})%
+            }%
+        }%
+    ]%
+  }
+  {\endtcolorbox}
+
+\RequirePackage{needspace}
+  
+\DeclareExerciseEnvironmentTemplate{runin}
+  {%
+    \par\vspace{\baselineskip}
+    \Needspace*{2\baselineskip}
+    \noindent
+    \textbf{\XSIMmixedcase{\GetExerciseName}~\GetExerciseProperty{counter}}%
+    \GetExercisePropertyT{subtitle}{ \textit{#1}} %
+    \GetExercisePropertyT{points}{%
+      \marginpar{%
+        \PropertyValue
+        \GetExercisePropertyT{bonus-points}{+\PropertyValue}%
+        \,\IfExerciseGoalSingularTF{points}
+            {\XSIMtranslate{point}}
+            {\XSIMtranslate{points}}%
+      }%
+    }%
+  }
+  {}
+
+\DeclareExerciseEnvironmentTemplate{margin}
+  {%
+    \par\vspace{\baselineskip}
+    \Needspace*{2\baselineskip}
+    \noindent
+    \llap{%
+      \smash{%
+        \tabular[t]{@{}r@{}}
+          \textbf{\XSIMmixedcase{\GetExerciseName}~\GetExerciseProperty{counter}}
+          \IfExercisePropertySetT{points}{%
+            \tabularnewline
+            (%
+              \GetExerciseProperty{points}%
+              \GetExercisePropertyT{bonus-points}{+#1}%
+              \,\XSIMtranslate{point-abbr}%
+            )%
+          }%
+        \endtabular
+      } % notice the space
+    }%
+  }
+  {}
+
+\DeclareExerciseProperty*{bonus}
+\DeclareExerciseEnvironmentTemplate{bonus}
+  {%
+    \subsection*
+      {%
+        \IfExerciseBooleanPropertyT{bonus}{\llap{$\bigstar$ }Bonus }%
+        \XSIMmixedcase{\GetExerciseName}\nobreakspace
+        \GetExerciseProperty{counter}%
+        \IfInsideSolutionF
+          {%
+            \IfExercisePropertySetT{subtitle}
+              { {\normalfont\itshape\GetExerciseProperty{subtitle}}}%
+          }%
+      }
+    \GetExercisePropertyT{points}
+      {%
+        \marginpar
+          {%
+            \IfInsideSolutionF{\rule{1.2cm}{1pt}\slash}%
+            \PropertyValue
+            \GetExercisePropertyT{bonus-points}
+              {\nobreakspace(+\PropertyValue)}%
+            \nobreakspace\XSIMtranslate{point-abbr}%
+          }%
+      }%
+  }
+  {}
+
+\DeclareExerciseType{problem}{
+  exercise-env = problem ,
+  solution-env = answer ,
+  exercise-name = Problem ,
+  solution-name = Answer ,
+  exercise-template = tcolorbox ,
+  solution-template = tcolorbox
+}
+
+\RequirePackage{hyperref,bookmark}
+
+\newcounter{examplefile}
+\newcounter{examplefiles}
+\newcommand*\xsim@add@example[1]{%
+  \listadd\xsim@examplefiles{#1}%
+  \stepcounter{examplefiles}%
+}
+\newcommand*\listexamplefiles{%
+  \def\do##1{%
+    \stepcounter{examplefile}%
+    \begin{cnltxcode}[
+      sidebyside align=top seam,sidebyside,
+      righthand width=\linewidth/4,
+      sidebyside gap=0pt,
+      lower separated=false,
+      title=Example~\theexamplefile\ \enquote{##1}
+        \href{../examples/xsim.##1.tex}{\color{white}[\TeX]}
+        \href{../examples/xsim.##1.pdf}{\color{white}[PDF]}%
+    ]
+    \lstinputlisting[style=cnltx,lastline=10]{../examples/xsim.##1.tex}
+    \tcblower
+    \fbox{%
+      \href{../examples/xsim.##1.pdf}{%
+        \includegraphics[width=.8\linewidth]{../examples/{xsim.##1}.pdf}}}%
+    \end{cnltxcode}
+  }%
+  \dolistloop\xsim@examplefiles
+}
+
+\xsim@add@example{blanks}
+\xsim@add@example{boxed-headings}
+\xsim@add@example{code-and-output}
+\xsim@add@example{collections}
+\xsim@add@example{crossref}
+\xsim@add@example{description-list}
+\xsim@add@example{different-point-types}
+\xsim@add@example{difficulties}
+\xsim@add@example{floating}
+\xsim@add@example{grade-distribution}
+\xsim@add@example{listings}
+\xsim@add@example{multiplechoice}
+\xsim@add@example{pointsums}
+\xsim@add@example{randomexercises}
+\xsim@add@example{various}
+\xsim@add@example{texsx-199360}
+\xsim@add@example{texsx-299534}
+\xsim@add@example{texsx-305110}
+\xsim@add@example{texsx-338165}
+\xsim@add@example{texsx-350028}
+\xsim@add@example{texsx-369065}
+\xsim@add@example{texsx-369636}
+\xsim@add@example{texsx-369803}
+\xsim@add@example{texwelt-6698}
+\xsim@add@example{texwelt-15093}
+\xsim@add@example{golatex-16824}
+\xsim@add@example{golatex-18844}
+
+\endinput
diff --git a/Master/texmf-dist/tex/latex/xsim/xsim.auxfile.code.tex b/Master/texmf-dist/tex/latex/xsim/xsim.auxfile.code.tex
new file mode 100644
index 00000000000..2a0f95846f3
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/xsim/xsim.auxfile.code.tex
@@ -0,0 +1,182 @@
+% ----------------------------------------------------------------------------
+% the XSIM package - auxfile module
+% 
+%   eXercise Sheets IMproved
+% 
+% ----------------------------------------------------------------------------
+% Clemens Niederberger
+% Web:    https://github.com/cgnieder/xsim
+% E-Mail: contact@mychemistry.eu
+% ----------------------------------------------------------------------------
+% Copyright 2017 Clemens Niederberger
+% 
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+% 
+% This work has the LPPL maintenance status `maintained'.
+% 
+% The Current Maintainer of this work is Clemens Niederberger.
+% ----------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% ----------------------------------------------------------------------------
+\XSIMmodule{auxfile}{writing stuff to the aux file}
+
+\cs_new_protected:Npn \xsim_write_to_aux:n #1
+  { \iow_now:Nn \@auxout {#1} }
+\cs_generate_variant:Nn \xsim_write_to_aux:n {x}
+
+% --------------------------------------------------------------------------
+
+\cs_new_protected:Npn \XSIM #1 { \use:c {XSIMaux#1} }
+
+\AtBeginDocument
+  {
+    \xsim_write_to_aux:x
+      { \token_to_str:N \providecommand \token_to_str:N \XSIM [1] {} }
+  }
+
+\cs_new_protected:Npn \xsim_new_aux_cs:cpn #1
+  { \cs_new_protected:cpn {XSIMaux#1} }
+
+\cs_new_protected:Npn \xsim_add_cs_to_aux:nn #1#2
+  {
+    \xsim_verbose:n { Writing~ command~ \XSIM {#1}~ to~ aux~ file }
+    \xsim_write_to_aux:x { \XSIM {#1} #2 }
+  }
+
+% ----------------------------------------------------------------------------
+% list for recording values that need to be written to the aux file and
+% updated at begin document
+
+% define list:
+% #1: name
+\cs_new_protected:Npn \xsim_new_list:n #1
+  {
+    \xsim_verbose:n { Defining~ new~ auxfile~ list~ `#1'. }
+    \prop_new:c {g__xsim_list_#1_prop}
+    \seq_new:c {g__xsim_list_#1_seq}
+    \seq_new:c {g__xsim_list_recorded_#1_seq}
+    \xsim_new_aux_cs:cpn {#1} ##1
+      {
+        \prop_gclear:c {g__xsim_list_#1_prop}
+        \tl_if_blank:nF {##1}
+          {
+            \seq_gset_split:cnx {g__xsim_list_#1_seq} {|}
+              { \tl_to_str:n {##1} }
+            \seq_map_inline:cn {g__xsim_list_#1_seq}
+              { \prop_gput:cnn {g__xsim_list_#1_prop} {####1} {} }
+          }
+      }
+    \AtBeginDocument
+      {
+        \seq_gclear:c {g__xsim_list_recorded_#1_seq}
+        \seq_set_eq:Nc \l__xsim_tmpa_seq {g__xsim_list_#1_seq}
+        \seq_map_inline:Nn \l__xsim_tmpa_seq
+          {
+            \str_set:Nn \l__xsim_tmpa_str {##1}
+            \seq_gput_right:cV {g__xsim_list_recorded_#1_seq} \l__xsim_tmpa_str
+          }
+        \seq_gremove_duplicates:c {g__xsim_list_recorded_#1_seq}
+      }
+  }
+
+% add to or remove from list:
+% #1: name
+% #2: entry
+\cs_new_protected:Npn \xsim_add_to_list:nn #1#2
+  {
+    \xsim_verbose:n { Adding~ `#2'~ to~ list~ `#1'. }
+    \str_set:Nn \l__xsim_tmpa_str {#2}
+    \prop_gput:cnn {g__xsim_list_#1_prop} {#2} {}
+    \seq_if_in:cVT {g__xsim_list_#1_seq} \l__xsim_tmpa_str
+      { \seq_gremove_all:cV {g__xsim_list_#1_seq} \l__xsim_tmpa_str }
+    \seq_gput_right:cV {g__xsim_list_#1_seq} \l__xsim_tmpa_str
+  }
+\cs_generate_variant:Nn \xsim_add_to_list:nn {nx}
+\cs_generate_variant:Nn \seq_if_in:NnT {cV}
+\cs_generate_variant:Nn \seq_gremove_all:Nn {cV}
+\cs_generate_variant:Nn \seq_gput_right:Nn {cV}
+\cs_generate_variant:Nn \seq_gset_split:Nnn {cnx}
+
+% #1: name
+% #2: entry
+\cs_new_protected:Npn \xsim_remove_from_list:nn #1#2
+  {
+    \xsim_verbose:n { Removing~ `#2'~ to~ list~ `#1'. }
+    \str_set:Nn \l__xsim_tmpa_str {#2}
+    \prop_if_in:cnT {g__xsim_list_#1_prop} {#2}
+      { \prop_gremove:cn {g__xsim_list_#1_prop} {#2} }
+    \seq_if_in:cVT {g__xsim_list_#1_seq} \l__xsim_tmpa_str
+      { \seq_gremove_all:cV {g__xsim_list_#1_seq} \l__xsim_tmpa_str }
+    \seq_if_in:cVT {g__xsim_list_recorded#1_seq} \l__xsim_tmpa_str
+      { \seq_gremove_all:cV {g__xsim_list_recorded_#1_seq} \l__xsim_tmpa_str }
+  }
+\cs_generate_variant:Nn \xsim_remove_from_list:nn {nx}
+
+% check if in list:
+% #1: name
+% #2: entry
+\prg_new_conditional:Npnn \xsim_if_in_list:nn #1#2 {p,T,F,TF}
+  {
+    \prop_if_in:cnTF {g__xsim_list_#1_prop} {#2}
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+\cs_generate_variant:Nn \xsim_if_in_list:nnTF {nx}
+\cs_generate_variant:Nn \xsim_if_in_list:nnT  {nx}
+
+\cs_new:Npn \xsim_list_show:n #1
+  { \prop_show:c {g__xsim_list_#1_prop}  }
+
+\bool_new:N \l__xsim_empty_lists_bool
+\cs_new_protected:Npn \xsim_empty_lists:
+  { \bool_set_true:N \l__xsim_empty_lists_bool }
+
+% update list -- should be used inside \AtEndDocument:
+% #1: name
+\cs_new_protected:Npn \xsim_update_list:n #1
+  {
+    \xsim_verbose:n { Updating~ list~ `#1'. }
+    \seq_remove_duplicates:c {g__xsim_list_#1_seq}
+    \seq_remove_duplicates:c {g__xsim_list_recorded_#1_seq}
+    \str_set:Nx \l__xsim_tmpa_str
+      { \seq_use:cn {g__xsim_list_#1_seq} {} }
+    \str_set:Nx \l__xsim_tmpb_str
+      { \seq_use:cn {g__xsim_list_recorded_#1_seq} {} }
+    \str_if_eq:NNF \l__xsim_tmpa_str \l__xsim_tmpb_str
+      { \xsim_rerun: }
+    \bool_if:NF \l__xsim_empty_lists_bool
+      {
+        \xsim_add_cs_to_aux:nn {#1}
+          { { \seq_use:cn {g__xsim_list_#1_seq} {|} } }
+      }
+  }
+
+% loop over list:
+% #1: name
+% #2: code
+\cs_new_protected:Npn \xsim_foreach_list_entry:nn #1#2
+  { \seq_map_inline:cn {g__xsim_list_recorded_#1_seq} {#2} }
+
+\cs_new_protected:Npn \xsim_foreach_new_list_entry:nn #1#2
+  { \seq_map_inline:cn {g__xsim_list_#1_seq} {#2} }
+
+% length of a list:
+% #1: name
+\cs_new:Npn \xsim_list_count:n #1
+  { \seq_count:c {g__xsim_list_recorded_#1_seq} }
+
+% item of a list:
+% #1: name
+% #2: integer
+\cs_new:Npn \xsim_list_item:nn #1#2
+  { \seq_item:cn {g__xsim_list_recorded_#1_seq} {#2} }
+
+% ----------------------------------------------------------------------------
+\tex_endinput:D
diff --git a/Master/texmf-dist/tex/latex/xsim/xsim.base.code.tex b/Master/texmf-dist/tex/latex/xsim/xsim.base.code.tex
new file mode 100644
index 00000000000..30be8b9d18f
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/xsim/xsim.base.code.tex
@@ -0,0 +1,169 @@
+% ----------------------------------------------------------------------------
+% the XSIM package - base module
+% 
+%   eXercise Sheets IMproved
+% 
+% ----------------------------------------------------------------------------
+% Clemens Niederberger
+% Web:    https://github.com/cgnieder/xsim
+% E-Mail: contact@mychemistry.eu
+% ----------------------------------------------------------------------------
+% Copyright 2017 Clemens Niederberger
+% 
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+% 
+% This work has the LPPL maintenance status `maintained'.
+% 
+% The Current Maintainer of this work is Clemens Niederberger.
+% ----------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% ----------------------------------------------------------------------------
+\XSIMmodule{base}{basic functionality of the package}
+
+\xsim_load_modules:n {auxfile}
+
+% ----------------------------------------------------------------------------
+% variants of kernel functions:
+\cs_generate_variant:Nn \seq_set_split:Nnn  {Nnx,NV}
+\cs_generate_variant:Nn \seq_gset_split:Nnn {c}
+\cs_generate_variant:Nn \seq_count:N        {c}
+\cs_generate_variant:Nn \seq_if_empty:NT    {c}
+\cs_generate_variant:Nn \prop_put:Nnn       {cxx}
+\cs_generate_variant:Nn \prop_gput:Nnn      {Nx,Nnx,cxx}
+\cs_generate_variant:Nn \prop_item:Nn       {c}
+\cs_generate_variant:Nn \prop_if_in:NnTF    {Nx}
+\cs_generate_variant:Nn \use:nn             {nx}
+\cs_generate_variant:Nn \file_input:n       {V,x}
+\cs_generate_variant:Nn \file_if_exist:nT   {V,x}
+\cs_generate_variant:Nn \file_if_exist:nTF  {V}
+\cs_generate_variant:Nn \msg_error:nnnnn    {nnnxx}
+\cs_generate_variant:Nn \keys_define:nn     {nx}
+\cs_generate_variant:Nn \keys_set:nn        {xn}
+\cs_generate_variant:Nn \tl_mixed_case:n    {x,f}
+\cs_generate_variant:Nn \tl_if_eq:nnTF      {ff,V}
+\cs_generate_variant:Nn \tl_if_eq:nnT       {x}
+\cs_generate_variant:Nn \tl_if_blank:nTF    {f}
+\cs_generate_variant:Nn \tl_set_rescan:Nnn  {Nnn}
+\cs_generate_variant:Nn \iow_now:Nn         {NV}
+\cs_generate_variant:Nn \str_if_eq:nnT      {x}
+\cs_generate_variant:Nn \iow_now:Nn         {NV}
+
+% ----------------------------------------------------------------------------
+% temporary variables:
+\tl_new:N    \l__xsim_tmpa_tl
+\tl_new:N    \l__xsim_tmpb_tl
+\tl_new:N    \l__xsim_tmpc_tl
+\tl_new:N    \l__xsim_tmpd_tl
+
+\str_new:N   \l__xsim_tmpa_str
+\str_new:N   \l__xsim_tmpb_str
+\str_new:N   \l__xsim_tmpc_str
+
+\bool_new:N  \l__xsim_tmpa_bool
+\bool_new:N  \l__xsim_tmpb_bool
+\bool_new:N  \l__xsim_tmpc_bool
+
+\dim_new:N   \l__xsim_tmpa_dim
+\dim_new:N   \l__xsim_tmpb_dim
+\dim_new:N   \l__xsim_tmpc_dim
+
+\seq_new:N   \l__xsim_tmpa_seq
+\seq_new:N   \l__xsim_tmpb_seq
+\seq_new:N   \l__xsim_tmpc_seq
+
+\int_new:N   \l__xsim_tmpa_int
+\int_new:N   \l__xsim_tmpb_int
+\int_new:N   \l__xsim_tmpc_int
+
+\box_new:N   \l__xsim_tmpa_box
+\box_new:N   \l__xsim_tmpb_box
+\box_new:N   \l__xsim_tmpc_box
+
+\clist_new:N \l__xsim_tmpa_clist
+\clist_new:N \l__xsim_tmpb_clist
+\clist_new:N \l__xsim_tmpc_clist
+
+% ----------------------------------------------------------------------------
+
+\prg_new_conditional:Npnn \xsim_if_komascript: {T,F,TF}
+  {
+    \cs_if_exist:cTF {KOMAClassName}
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+% ----------------------------------------------------------------------------
+
+\prg_new_conditional:Npnn \xsim_if_final: {p,T,F,TF}
+  {
+    \bool_if:NTF \g_xsim_final_bool
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+\prg_new_conditional:Npnn \xsim_if_verbose: {p,T,F,TF}
+  {
+    \bool_if:NTF \g_xsim_verbose_bool
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+\prg_new_conditional:Npnn \xsim_if_rerun: {p,T,F,TF}
+  {
+    \bool_if:NTF \g__xsim_rerun_bool
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+\prg_new_conditional:Npnn \xsim_if_clear_aux: {p,T,F,TF}
+  {
+    \xsim_if_final:TF
+      { \prg_return_false: }
+      {
+        \bool_if:NTF \g_xsim_clear_aux_bool
+          { \prg_return_true: }
+          { \prg_return_false: }
+      }
+  }
+
+\cs_new_protected:Npn \xsim_verbose:n #1
+  { \xsim_if_verbose:T { \msg_info:nnn {xsim} {verbose} {#1} } }
+\cs_generate_variant:Nn \xsim_verbose:n {x}
+
+\cs_new_protected:Npn \xsim_rerun:
+  { \bool_gset_true:N \g__xsim_rerun_bool }
+
+\prg_new_conditional:Npnn \xsim_if_chapter: {p,T,F,TF}
+  {
+    \bool_if:nTF
+      { \cs_if_exist_p:N \chapter && \cs_if_exist_p:N \c@chapter }
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+% ----------------------------------------------------------------------------
+
+% #1: macro name
+% #2: 0 to 9 times `n' (= number of arguments of internal item)
+% #3: code; may contain a suiting \__xsim_loop_item:<nnn>
+\cs_new_protected:Npn \xsim_define_loop_macro:Nnn #1#2#3
+  {
+    \xsim_verbose:n { Defining~ loop~ macro~ #1 }
+    \cs_new_protected:Npn #1 ##1##2
+      { \cs_set:cn {__xsim_loop_item:#2} {##2} #3 }
+  }
+
+% ----------------------------------------------------------------------------
+
+\cs_new_protected:Npn \xsim_setup:n #1
+  { \keys_set:nn {xsim} {#1} }
+
+% ----------------------------------------------------------------------------
+\tex_endinput:D
diff --git a/Master/texmf-dist/tex/latex/xsim/xsim.blanks.code.tex b/Master/texmf-dist/tex/latex/xsim/xsim.blanks.code.tex
new file mode 100644
index 00000000000..323b7bd52f9
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/xsim/xsim.blanks.code.tex
@@ -0,0 +1,154 @@
+% ----------------------------------------------------------------------------
+% the XSIM package - blanks module
+% 
+%   eXercise Sheets IMproved
+% 
+% ----------------------------------------------------------------------------
+% Clemens Niederberger
+% Web:    https://github.com/cgnieder/xsim
+% E-Mail: contact@mychemistry.eu
+% ----------------------------------------------------------------------------
+% Copyright 2017 Clemens Niederberger
+% 
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+% 
+% This work has the LPPL maintenance status `maintained'.
+% 
+% The Current Maintainer of this work is Clemens Niederberger.
+% ----------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% ----------------------------------------------------------------------------
+\XSIMmodule{blanks}{add blanks, cloze}
+
+\bool_new:N \l__xsim_blank_width_bool
+\bool_new:N \l__xsim_blank_linespread_bool
+\tl_new:N   \l__xsim_blank_linespread_tl
+\tl_new:N   \l__xsim_blank_scale_tl
+\dim_new:N  \l__xsim_blank_dim
+\dim_new:N  \l__xsim_blank_line_increment_dim
+\dim_new:N  \l__xsim_blank_line_minimum_length_dim
+\box_new:N  \l__xsim_blank_box
+
+\cs_new_protected:Npn \xsim_write_cloze_blank:n #1 {#1}
+\cs_new_protected:Npn \xsim_write_cloze_filled:n #1 {#1}
+
+\keys_define:nn {xsim/blank}
+  {
+    blank-style         .code:n    =
+      \cs_set_protected:Npn \xsim_write_cloze_blank:n ##1 {#1} ,
+    blank-style         .initial:n = \underline {#1} ,
+    filled-style        .code:n    =
+      \cs_set_protected:Npn \xsim_write_cloze_filled:n ##1 {#1} ,
+    filled-style        .initial:n = \underline {#1} ,
+    style               .meta:n    =
+      {
+        blank-style = #1 ,
+        filled-style = #1
+      } ,
+    scale               .tl_set:N  = \l__xsim_blank_scale_tl ,
+    scale               .initial:n = 1 ,
+    width               .code:n    =
+      {
+        \bool_set_true:N \l__xsim_blank_width_bool
+        \dim_set:Nn \l__xsim_blank_dim {#1}
+      } ,
+    linespread          .code:n    =
+      \bool_set_true:N \l__xsim_blank_linespread_bool
+      \tl_set:Nn \l__xsim_blank_linespread_tl {#1} ,
+    linespread          .initial:n = 1 ,
+    line-increment      .dim_set:N = \l__xsim_blank_line_increment_dim ,
+    line-increment      .initial:n = 1pt ,
+    line-minimum-length .dim_set:N = \l__xsim_blank_line_minimum_length_dim ,
+    line-minimum-length .initial:n = 2em
+  }
+
+\cs_new_protected:Npn \xsim_blank:n #1
+  {
+    \box_clear:N \l__xsim_blank_box
+    \mode_if_math:TF
+      { \hbox_set:Nn \l__xsim_blank_box { $ \m@th \mathpalette{}{#1} $ } }
+      { \hbox_set:Nn \l__xsim_blank_box {#1} }
+    \xsim_if_inside_solution:TF
+      { \xsim_write_cloze_filled:n {#1} }
+      {
+        \bool_if:NTF \l__xsim_blank_width_bool
+          { \__xsim_blank_skip:V \l__xsim_blank_dim }
+          { \__xsim_blank_skip:n { \box_wd:N \l__xsim_blank_box } }
+      }
+  }
+  
+\cs_new_protected:Npn \__xsim_blank_skip:n #1
+  {
+    \bool_if:NTF \l__xsim_blank_width_bool
+      { \dim_set:Nn \l__xsim_tmpa_dim {#1} }
+      {
+        \fp_set:Nn \l__xsim_tmpa_fp
+          { \dim_to_fp:n {#1} * \l__xsim_blank_scale_tl }
+        \dim_set:Nn \l__xsim_tmpa_dim { \fp_to_dim:N \l__xsim_tmpa_fp }
+      }
+    \dim_compare:nTF
+      { \l__xsim_tmpa_dim > \l__xsim_blank_line_minimum_length_dim }
+      {
+        \mode_if_math:TF
+          { \xsim_write_cloze_blank:n { \skip_horizontal:N \l__xsim_tmpa_dim } }
+          {
+            \dim_do_while:nn { \l__xsim_tmpa_dim > \c_zero_dim }
+              {
+                % I wonder what the correct l3 way would be -- if there is
+                % one, yet:
+                \tex_hfil:D
+                \tex_penalty:D \hyphenpenalty
+                \tex_hfilneg:D
+                \dim_compare:nTF
+                  { \l__xsim_tmpa_dim < \l__xsim_blank_line_increment_dim }
+                  { \xsim_write_cloze_blank:n { \skip_horizontal:N \l__xsim_tmpa_dim } }
+                  {
+                    \xsim_write_cloze_blank:n
+                      { \skip_horizontal:N \l__xsim_blank_line_increment_dim }
+                  }
+                \dim_sub:Nn \l__xsim_tmpa_dim { \l__xsim_blank_line_increment_dim }
+              }
+          }
+      }
+      { \xsim_write_cloze_blank:n { \skip_horizontal:N \l__xsim_tmpa_dim } }
+  }
+\cs_generate_variant:Nn \__xsim_blank_skip:n { V }
+
+% ----------------------------------------------------------------------------
+\tex_endinput:D
+
+the following code from Heiko Oberdieck in d.c.t.t served as inspiration
+and basis for the \blank command:
+https://groups.google.com/d/msg/de.comp.text.tex/fZLwraH04jE/o1RSdFXjGuIJ
+
+\makeatletter
+\newcommand*{\luecke}{%
+  \begingroup
+    \setlength{\dimen@}{6cm}%
+    \ifdim\dimen@>2em %
+      \underline{\hspace{1em}}%
+      \advance\dimen@ by -2em\relax
+      \@whiledim\dimen@>0pt\do{%
+        \penalty\hyphenpenalty
+        \ifdim\dimen@<1pt %
+          \underline{\hspace{\dimen@}}%
+        \else
+          \underline{\hspace{1pt}}%
+        \fi
+        \advance\dimen@ by -1pt %
+      }%
+      \underline{\hspace{1em}}%
+    \else
+      \underline{\hspace{\dimen@}}%
+    \fi
+  \endgroup
+  \xspace
+}
+\makeatother
diff --git a/Master/texmf-dist/tex/latex/xsim/xsim.collections.code.tex b/Master/texmf-dist/tex/latex/xsim/xsim.collections.code.tex
new file mode 100644
index 00000000000..8bf0c0bc705
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/xsim/xsim.collections.code.tex
@@ -0,0 +1,395 @@
+% ----------------------------------------------------------------------------
+% the XSIM package - collections module
+% 
+%   eXercise Sheets IMproved
+% 
+% ----------------------------------------------------------------------------
+% Clemens Niederberger
+% Web:    https://github.com/cgnieder/xsim
+% E-Mail: contact@mychemistry.eu
+% ----------------------------------------------------------------------------
+% Copyright 2017 Clemens Niederberger
+% 
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+% 
+% This work has the LPPL maintenance status `maintained'.
+% 
+% The Current Maintainer of this work is Clemens Niederberger.
+% ----------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% ----------------------------------------------------------------------------
+\XSIMmodule{collections}{collect exercises and print collected exercises}
+
+\xsim_load_modules:n {base}
+
+\prop_new:N \g__xsim_collections_prop
+\bool_new:N \l____xsim_active_bool
+
+\msg_new:nnn {xsim} {collection-exists}
+  {
+    The~ collection~ `#1'~ you're~ trying~ to~ define~ \msg_line_context:
+    \c_space_tl already~ exists.
+  }
+
+\msg_new:nnn {xsim} {collection-active}
+  {
+    You~ can't~ print~ collection~ `#1'~ while~ it~ is~ still~ active~
+    \msg_line_context:
+  }
+
+\msg_new:nnn {xsim} {unknown-collection}
+  {
+    You're~ trying~ to~ use~ the~ collection~ `#1'~ \msg_line_context:
+    \c_space_tl but~ no~ collection~ with~ that~ name~ exists.~ You~ need~ to~
+    define~ it~ first!
+  }
+
+\msg_new:nnn {xsim} {print-collection-choice}
+  {
+    The~ choice~ `#1'~ for~ the~ option~ `print-collection/print'~ does~ not~
+    exist.~ I'm~ using~ `exercises'~ instead~ \msg_line_context:
+  }
+
+% ----------------------------------------------------------------------------
+
+% #1: collection name
+\cs_new_protected:Npn \xsim_new_collection:n #1
+  {
+    \xsim_if_collection_exists:nTF {#1}
+      { \msg_error:nnn {xsim} {collection-exists} {#1} }
+      {
+        \xsim_verbose:n { Declaring~ new~ collection~ `#1'. }
+        \prop_gput:Nnn \g__xsim_collections_prop {#1} { \c_false_bool }
+        \xsim_new_list:n {collection:#1}
+        \seq_new:c {g__xsim_collection_#1_seq}
+      }
+  }
+
+% #1: collection name
+\prg_new_conditional:Npnn \xsim_if_collection_exists:n #1 {T,F,TF}
+  {
+    \prop_if_in:NnTF \g__xsim_collections_prop {#1}
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+\xsim_new_collection:n {all~ exercises}
+
+\cs_new_protected:Npn \xsim_foreach_collection:n #1
+  { \prop_map_inline:Nn \g__xsim_collections_prop {#1} }
+
+% ----------------------------------------------------------------------------
+
+% #1: collection name
+% #2: type
+\cs_new_protected:Npn \xsim_activate_collection:nn #1#2
+  {
+    \xsim_if_collection_active:nTF {#1}
+      { % TODO: error
+      }
+      {
+        \xsim_verbose:n { Activating~ collection~ `#1'. }
+        \prop_gput:Nnn \g__xsim_collections_prop {#1} { \c_true_bool }
+        \tl_if_blank:nF {#2}
+          { \seq_gput_right:cn {g__xsim_collection_#1_seq} {#2} }
+      }
+  }
+
+\cs_new_protected:Npn \xsim_activate_collection:n #1
+  { \xsim_activate_collection:nn {#1} {} }
+
+% #1: collection name
+\cs_new_protected:Npn \xsim_deactivate_collection:n #1
+  {
+    \xsim_if_collection_active:nTF {#1}
+      {
+        \xsim_verbose:n { Deactivating~ collection~ `#1'. }
+        \prop_gput:Nnn \g__xsim_collections_prop {#1} { \c_false_bool }
+        \seq_gclear:c {g__xsim_collection_#1_seq}
+      }
+      { % TODO: warning
+      }
+  }
+
+% start collection for an exercise type:
+% #1: collection name
+% #2: type
+\cs_new_protected:Npn \xsim_start_collection:nn #1#2
+  {
+    \group_begin:
+    \xsim_if_collection_exists:nF {#1}
+      { \msg_error:nnn {xsim} {unknown-collection} {#1} }
+    \xsim_activate_collection:nn {#1} {#2}
+    \xsim_setup:n { #2/print = false }
+  }
+
+% start collection for all exercise types:
+% #1: collection name
+\cs_new_protected:Npn \xsim_start_collection:n #1
+  {
+    \group_begin:
+    \xsim_if_collection_exists:nF {#1}
+      { \msg_error:nnn {xsim} {unknown-collection} {#1} }
+    \xsim_activate_collection:n {#1}
+    \xsim_foreach_exercise_type:n
+      { \xsim_setup:n { ##1/print = false } }
+  }
+
+% stop collection:
+% #1: collection name
+\cs_new_protected:Npn \xsim_stop_collection:n #1
+  {
+    \xsim_deactivate_collection:n {#1}
+    \group_end:
+  }
+
+% ----------------------------------------------------------------------------
+
+% #1: collection name
+% #2: type
+% #3: id
+\cs_new_protected:Npn \xsim_add_to_collection:nnn #1#2#3
+  {
+    \seq_if_empty:cTF {g__xsim_collection_#1_seq}
+      { \__xsim_add_to_collection:nnn {#1} {#2} {#3} }
+      {
+        \seq_if_in:cnT {g__xsim_collection_#1_seq} {#2}
+          { \__xsim_add_to_collection:nnn {#1} {#2} {#3} }
+      }
+  }
+
+% #1: collection name
+% #2: type
+% #3: id
+\cs_new_protected:Npn \__xsim_add_to_collection:nnn #1#2#3
+  {
+    \xsim_verbose:n
+      { Adding~ exercise~ type~ `#2'~ id~ `#3'~ to~ collection~ `#1'. } 
+    \xsim_add_to_list:nn {collection:#1} {#2-#3}
+  }
+
+\cs_new:Npn \xsim_collection_count:n #1
+  { \xsim_list_count:n {collection:#1} }
+
+% #1: type
+% #2: id
+\cs_new_protected:Npn \xsim_update_collections:nn #1#2
+  {
+    \xsim_if_insert_mode:F
+      {
+        \xsim_exercise_if_use:nnT {#1} {#2}
+          { \xsim_add_to_collection:nnn {all~ exercises} {#1} {#2} }
+        \xsim_foreach_collection:n
+          {
+            \xsim_exercise_if_use:nnTF {#1} {#2}
+              {
+                \xsim_if_collection_active:nT {##1}
+                  { \xsim_add_to_collection:nnn {##1} {#1} {#2} }
+              }
+              { \xsim_remove_from_list:nn {collection:##1} {#1-#2} }
+          }
+      }
+  }
+\cs_generate_variant:Nn \xsim_update_collections:nn {nV}
+
+% #1: collection name
+\cs_new_protected:Npn \xsim_get_collections:
+  {
+    \xsim_foreach_collection:n
+      {
+        \xsim_foreach_list_entry:nn {collection:##1}
+          { \__xsim_list_to_collection:nww {##1} ####1 \q_stop }
+      }
+  }
+
+\cs_new_protected:Npn \__xsim_list_to_collection:nww #1#2-#3 \q_stop
+  { \xsim_add_to_collection:nnn {#1} {#2} {#3} }
+
+% ----------------------------------------------------------------------------
+
+% #1: collection name
+% #2: type
+% #3: id
+\prg_new_conditional:Npnn \xsim_if_in_collection:nnn #1#2#3 {T,F,TF}
+  {
+    \xsim_if_in_list:nnTF {collection:#1} {#2-#3}
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+\cs_generate_variant:Nn \xsim_if_in_collection:nnnTF {V}
+\cs_generate_variant:Nn \xsim_if_in_collection:nnnT  {x,nV}
+
+% ----------------------------------------------------------------------------
+
+\bool_new:N \l__xsim_printcollection_headings_bool
+\tl_new:N   \l__xsim_printcollection_headings_template_tl
+\tl_new:N   \l__xsim_print_collection_choice_tl
+
+\keys_define:nn {xsim/print-collection}
+  {
+    headings          .bool_set:N = \l__xsim_printcollection_headings_bool ,
+    headings          .initial:n  = false ,
+    headings-template .tl_set:N  = \l__xsim_printcollection_headings_template_tl ,
+    headings-template .initial:n = collection ,
+    print             .choice: ,
+    print/exercises   .code:n =
+      \tl_set:Nn \l__xsim_print_collection_choice_tl {exercise} ,
+    print/solutions   .code:n =
+      \tl_set:Nn \l__xsim_print_collection_choice_tl {solution} ,
+    print/both        .code:n =
+      \tl_set:Nn \l__xsim_print_collection_choice_tl {both} ,
+    print/unknown     .code:n =
+      \msg_warning:nnn {xsim} {print-collection-choice} {#1}
+      \tl_set:Nn \l__xsim_print_collection_choice_tl {exercise} ,
+    print             .initial:n = exercises
+  }
+
+% #1: options
+% #2: collection name
+\cs_new_protected:Npn \xsim_print_collection:nn #1#2
+  {
+    \xsim_if_collection_active:nTF {#2}
+      { \msg_error:nnn {xsim} {collection-active} {#2} }
+      {
+        \xsim_verbose:x
+          {
+            Printing~
+            \l__xsim_print_collection_choice_tl \c_space_tl
+            \str_if_eq:onT { \l__xsim_print_collection_choice_tl } {both}
+              { exercises~ and~ solutions~ }
+            of~ collection~ `#2'
+          }
+        \group_begin:
+          \keys_set:nn {xsim/print-collection} {#1} 
+          \tl_set:Nn \ExerciseCollection {#2}
+          \xsim_foreach_exercise_type:n
+            {
+              \tl_set:Nn \ExerciseType {##1}
+              \bool_if:NT \l__xsim_printcollection_headings_bool
+                {
+                  \bool_set_false:N \l__xsim_tmpa_bool
+                  \xsim_foreach_exercise_id:n
+                    {
+                      \xsim_if_in_collection:nnnT {#2} {##1} {####1}
+                        {
+                          \tl_if_eq:VnTF
+                            \l__xsim_print_collection_choice_tl
+                            {both}
+                            {
+                              \xsim_if_exercise_exists:nnT {##1} {####1}
+                                { \bool_set_true:N \l__xsim_tmpa_bool }
+                            }
+                            {
+                              \use:c
+                                {
+                                  xsim_if_
+                                  \l__xsim_print_collection_choice_tl
+                                  _exists:nnT
+                                }
+                                {##1}
+                                {####1}
+                                { \bool_set_true:N \l__xsim_tmpa_bool }
+                            }
+                        }
+                    }
+                  \bool_if:NT \l__xsim_tmpa_bool
+                    {
+                      \xsim_use_template:nV
+                      {heading}
+                      \l__xsim_printcollection_headings_template_tl
+                    }
+                }
+              \xsim_foreach_exercise_id:n
+                {
+                  \xsim_if_in_collection:nnnT {#2} {##1} {####1}
+                    {
+                      \tl_if_eq:VnTF
+                        \l__xsim_print_collection_choice_tl
+                        {both}
+                        {
+                          \xsim_if_exercise_exists:nnT {##1} {####1}
+                            { \xsim_insert:nnnn {##1} {####1} {} {exercise} }
+                          \xsim_if_solution_exists:nnT {##1} {####1}
+                            { \xsim_insert:nnnn {##1} {####1} {} {solution} }
+                        }
+                        {
+                          \use:c
+                            {
+                              xsim_if_
+                              \l__xsim_print_collection_choice_tl
+                              _exists:nnT
+                            }
+                            {##1}
+                            {####1}
+                            {
+                              \xsim_insert:nnnV
+                                {##1}
+                                {####1}
+                                {}
+                                \l__xsim_print_collection_choice_tl
+                            }
+                        }
+                    }
+                }
+            }
+        \group_end:
+      }
+  }
+
+% ----------------------------------------------------------------------------
+
+% #1: collection name
+\prg_new_conditional:Npnn \xsim_if_collection_active:n #1 {T,F,TF}
+  {
+    \prop_if_in:NnTF \g__xsim_collections_prop {#1}
+      {
+        \bool_if:nTF
+          {
+            !\str_if_eq_x_p:nn {#1} {all~ exercises} &&
+            \prop_item:Nn \g__xsim_collections_prop {#1}
+          }
+          { \prg_return_true: }
+          { \prg_return_false: }
+      }
+      { \prg_return_false: }
+  }
+
+\prg_new_protected_conditional:Npnn \xsim_if_collections_active: {T,F,TF}
+  {
+    \bool_set_false:N \l____xsim_active_bool
+    \prop_map_inline:Nn \g__xsim_collections_prop
+      {
+        \xsim_if_collection_active:nT {##1}
+          {
+            \bool_set_true:N \l____xsim_active_bool
+            \prop_map_break:
+          }
+      }
+    \bool_if:NTF \l____xsim_active_bool
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+% ----------------------------------------------------------------------------
+
+\AtBeginDocument
+  {
+    \xsim_get_collections:
+    \xsim_activate_collection:n   {all~ exercises}
+  }
+
+\AtEndDocument
+  {
+    \xsim_deactivate_collection:n {all~ exercises}
+    \xsim_foreach_collection:n { \xsim_update_list:n {collection:#1} }
+  }
+  
+% ----------------------------------------------------------------------------
+\tex_endinput:D
diff --git a/Master/texmf-dist/tex/latex/xsim/xsim.definitions.code.tex b/Master/texmf-dist/tex/latex/xsim/xsim.definitions.code.tex
new file mode 100644
index 00000000000..a30c44a76fc
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/xsim/xsim.definitions.code.tex
@@ -0,0 +1,430 @@
+% ----------------------------------------------------------------------------
+% the XSIM package - definitions module
+% 
+%   eXercise Sheets IMproved
+% 
+% ----------------------------------------------------------------------------
+% Clemens Niederberger
+% Web:    https://github.com/cgnieder/xsim
+% E-Mail: contact@mychemistry.eu
+% ----------------------------------------------------------------------------
+% Copyright 2017 Clemens Niederberger
+% 
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+% 
+% This work has the LPPL maintenance status `maintained'.
+% 
+% The Current Maintainer of this work is Clemens Niederberger.
+% ----------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% ----------------------------------------------------------------------------
+\XSIMmodule{definitions}{definition of user commands}
+
+\xsim_load_modules:n {base,exercises,blanks,translations,interface,grades,random}
+
+% not exactly a user choice: the `exercises' environments rely on them:
+\DeclareExerciseParameter*!{exercise-env}
+\DeclareExerciseParameter*!{solution-env}
+\DeclareExerciseParameter !{exercise-name}
+\DeclareExerciseParameter !{solution-name}
+\DeclareExerciseParameter !{exercise-template}
+\DeclareExerciseParameter !{solution-template}
+\DeclareExerciseParameter* {counter}
+\DeclareExerciseParameter* {solution-counter}
+\DeclareExerciseParameter* {number}
+
+% ----------------------------------------------------------------------------
+
+% not exactly a user choice, must be present at various places:
+\DeclareExerciseProperty!  {id}
+\DeclareExerciseProperty!  {ID}
+\DeclareExerciseProperty   {counter}
+\DeclareExerciseProperty   {counter-value}
+\DeclareExerciseProperty * {print}
+\DeclareExerciseProperty *-{print!}
+\DeclareExerciseProperty * {use}
+\DeclareExerciseProperty * {used}
+\DeclareExerciseProperty *-{use!}
+\XSIMifchapterT{
+  \DeclareExerciseProperty {chapter-value}
+  \DeclareExerciseProperty {chapter}
+}
+\DeclareExerciseProperty  {section-value}
+\DeclareExerciseProperty  {section}
+
+% those are additional and wouldn't *need* to be present except for
+% pre-defined templates which make use of them:
+\DeclareExerciseProperty  {subtitle}
+\DeclareExerciseProperty  {points}
+\DeclareExerciseProperty  {bonus-points}
+\DeclareExerciseProperty  {page-value}
+\DeclareExerciseProperty  {page}
+
+\DeclareExercisePropertyAlias {ID} {id}
+
+% ----------------------------------------------------------------------------
+
+\DeclareExerciseTagging {tags}
+\DeclareExerciseTagging {topics}
+
+\xsimsetup{tags/ingore-untagged=false}
+
+% ----------------------------------------------------------------------------
+
+\DeclareExerciseGoal {points}
+\DeclareExerciseGoal {bonus-points}
+
+\NewDocumentCommand \printgoal {m}
+  { \ExerciseGoalValuePrint {#1} {} {} }
+
+\NewDocumentCommand \points {m}
+  {
+    \ExerciseGoalValuePrint {#1}
+      { \, \XSIMtranslate {point} }
+      { \, \XSIMtranslate {points} }
+  }
+
+\NewDocumentCommand \addpoints {sm}
+  {
+    \AddtoExerciseGoal {points} {#2}
+    \IfBooleanF {#1} { \points {#2} }
+  }
+
+\NewDocumentCommand \printpoints {m}
+  {
+    \TotalExerciseTypeGoal {#1} {points}
+      { \, \XSIMtranslate {point} }
+      { \, \XSIMtranslate {points} }
+  }
+
+\NewDocumentCommand \printtotalpoints {}
+  {
+    \TotalExerciseGoal {points}
+      { \, \XSIMtranslate {point} }
+      { \, \XSIMtranslate {points} }
+  }
+
+\NewDocumentCommand \addbonus {sm}
+  {
+    \AddtoExerciseGoal {bonus-points} {#2}
+    \IfBooleanF {#1} { \points {#2} }
+  }
+
+\NewDocumentCommand \printbonus {m}
+  {
+    \TotalExerciseTypeGoal {#1} {bonus-points}
+      { \, \XSIMtranslate {point} }
+      { \, \XSIMtranslate {points} }
+  }
+
+\NewDocumentCommand \printtotalbonus {}
+  {
+    \TotalExerciseGoal {bonus-points}
+      { \, \XSIMtranslate {point} }
+      { \, \XSIMtranslate {points} }
+  }
+
+% ----------------------------------------------------------------------------
+\NewDocumentCommand \pointsforgrade {m}
+  {
+    \GetGradeRequirementForGoal {#1} {points}
+      { \, \XSIMtranslate {point} }
+      { \, \XSIMtranslate {points} }
+  }
+
+\NewDocumentCommand \goalsforgrade {mm}
+  {
+    \GetGradeRequirementForGoals {#2} {#1}
+      { \, \XSIMtranslate {point} }
+      { \, \XSIMtranslate {points} }
+  }
+
+\NewDocumentCommand \totalgoalforgrade {m}
+  {
+    \GetGradeRequirement {#1}
+      { \, \XSIMtranslate {point} }
+      { \, \XSIMtranslate {points} }
+  }
+
+% ----------------------------------------------------------------------------
+
+\DeclareExerciseType {exercise} {
+  exercise-env      = exercise ,
+  solution-env      = solution ,
+  exercise-name     = \XSIMtranslate {exercise} ,
+  solution-name     = \XSIMtranslate {solution} ,
+  exercise-template = default ,
+  solution-template = default
+}
+
+% ----------------------------------------------------------------------------
+
+\DeclareExerciseEnvironmentTemplate {default}
+  {
+    \subsection*
+      {
+        \XSIMmixedcase { \GetExerciseName } \nobreakspace
+        \GetExerciseProperty {counter}
+        \IfInsideSolutionF
+          {
+            \IfExercisePropertySetT {subtitle}
+              { ~ { \normalfont \itshape \GetExerciseProperty {subtitle} } }
+          }
+      }
+    \GetExercisePropertyT {points}
+      {
+        \marginpar
+          {
+            \IfInsideSolutionF { \rule {1.2cm} {1pt} \slash }
+            \PropertyValue
+            \GetExercisePropertyT {bonus-points}
+              { \nobreakspace ( + \PropertyValue ) }
+            \nobreakspace\XSIMtranslate {point-abbr}
+          }
+      }
+  }
+  {}
+
+% ----------------------------------------------------------------------------
+
+\DeclareExerciseHeadingTemplate {none} {}
+
+\DeclareExerciseHeadingTemplate {default}
+  { \section* { \XSIMtranslate {default-heading} } }
+
+\DeclareExerciseHeadingTemplate {collection}
+  { \section* { \XSIMtranslate {collection-heading} } }
+
+\DeclareExerciseHeadingTemplate {per-section}
+  { \section* { \XSIMtranslate {per-section-heading} } }
+  
+\DeclareExerciseHeadingTemplate {per-chapter}
+  { \section* { \XSIMtranslate {per-chapter-heading} } }
+
+% ----------------------------------------------------------------------------
+
+\RequirePackage{array,booktabs}
+
+\DeclareExerciseTableTemplate {default*}
+  {
+    \XSIMputright \ExerciseTableCode
+      {
+        \toprule
+        \XSIMifblankTF {\ExerciseType}
+          {}
+          { \XSIMmixedcase { \GetExerciseParameter {exercise-name} } }
+        &
+      }
+    \ForEachUsedExerciseByType
+      {
+        \XSIMifeqTF {#1} { \ExerciseTableType {#1} }
+          {
+            \XSIMifblankTF { \ExerciseType }
+              {
+                \XSIMputright \ExerciseTableCode
+                  {
+                    \XSIMmixedcase
+                      { \ExerciseParameterGet {#1} {exercise-name} ~ }
+                  }
+              }
+              {}
+            \XSIMputright \ExerciseTableCode { #3 & }
+          }
+          {}
+      }
+    \XSIMputright \ExerciseTableCode
+      {
+        \XSIMtranslate {total} \\
+        \midrule \XSIMmixedcase { \XSIMtranslate {points} } &
+      }
+    \ForEachUsedExerciseByType
+      {
+        \XSIMifeqTF {#1} { \ExerciseTableType {#1} }
+          {
+            \XSIMputright \ExerciseTableCode
+              { \XSIMifblankTF {#5} {\printgoal{0}} {\printgoal{#5}} & }
+          }
+          {}
+      }
+    \XSIMputright \ExerciseTableCode
+      {
+        \XSIMifblankTF {\ExerciseType}
+          { \TotalExerciseGoal {points} {} {} }
+          { \TotalExerciseTypeGoal {\ExerciseType} {points} {} {} }
+        \\ \midrule
+        \XSIMtranslate {reached} &
+      }
+    \ForEachUsedExerciseByType
+      {
+        \XSIMifeqTF {#1} { \ExerciseTableType {#1} }
+          { \XSIMputright \ExerciseTableCode {&} }
+          {}
+      }
+    \XSIMputright \ExerciseTableCode { \\ \bottomrule }
+    \def\numberofcolumns{
+      \XSIMifblankTF {\ExerciseType}
+        {\numberofusedexercises}
+        {\csname numberof \ExerciseType s\endcsname}
+      }
+    \XSIMifeqF{\numberofcolumns}{0}
+      {
+        \begin {tabular} {l*{\numberofcolumns}{c}c}
+          \ExerciseTableCode
+        \end {tabular}
+      }
+  }
+
+\DeclareExerciseTableTemplate {default}
+  {
+    \XSIMputright \ExerciseTableCode
+      {
+        \toprule
+        \XSIMifblankTF {\ExerciseType}
+          {}
+          { \XSIMmixedcase { \GetExerciseParameter {exercise-name} } }
+        &
+        \XSIMmixedcase { \XSIMtranslate {points} } &
+        \XSIMtranslate {reached} \\
+        \midrule
+      }
+    \ForEachUsedExerciseByType
+      {
+        \XSIMifeqTF {#1} { \ExerciseTableType {#1} }
+          {
+            \XSIMifblankTF { \ExerciseType }
+              {
+                \XSIMputright \ExerciseTableCode
+                  {
+                    \XSIMmixedcase
+                      { \ExerciseParameterGet {#1} {exercise-name} ~ }
+                  }
+              }
+              {}
+            \XSIMputright \ExerciseTableCode
+              { #3 & \XSIMifblankTF {#5} {\printgoal{0}} {\printgoal{#5}} & \\ }
+          }
+          {}
+      }
+    \XSIMputright \ExerciseTableCode
+      {
+        \midrule
+        \XSIMtranslate {total} &
+        \XSIMifblankTF {\ExerciseType}
+          { \TotalExerciseGoal {points} {} {} }
+          { \TotalExerciseTypeGoal {\ExerciseType} {points} {} {} } &
+        \\ \bottomrule
+      }
+    \XSIMexpandcode
+      {
+        \noexpand \begin {tabular} {\XSIMifblankTF{\ExerciseType}{l}{c}cc}
+          \noexpand \ExerciseTableCode
+        \noexpand \end {tabular}
+      }
+  }
+
+% ----------------------------------------------------------------------------
+
+\DeclareExerciseTranslations {exercise} {
+  Fallback = exercise ,
+  English  = exercise ,
+  French   = exercice ,
+  German   = \"Ubung
+}
+
+\DeclareExerciseTranslations {question} {
+  Fallback = question ,
+  English  = question ,
+  French   = question ,
+  German   = Aufgabe
+}
+
+\DeclareExerciseTranslations {solution} {
+  Fallback = solution ,
+  English  = solution ,
+  French   = solution ,
+  German   = L\"osung
+}
+
+\DeclareExerciseTranslations {point-abbr} {
+  Fallback = p. ,
+  English  = p. ,
+  French   = p. ,
+  German   = P.
+}
+
+\DeclareExerciseTranslations {point} {
+  Fallback = point ,
+  English  = point ,
+  French   = point ,
+  German   = Punkt
+}
+
+\DeclareExerciseTranslations {points} {
+  Fallback = points ,
+  English  = points ,
+  French   = points ,
+  German   = Punkte
+}
+
+\DeclareExerciseTranslations {reached} {
+  Fallback = reached ,
+  English  = reached ,
+  French   = atteint ,
+  German   = erreicht
+}
+
+\DeclareExerciseTranslations {total} {
+  Fallback = total ,
+  English  = total ,
+  French   = totalement ,
+  German   = insgesamt
+}
+
+\DeclareExerciseTranslations {default-heading} {
+  Fallback = \XSIMmixedcase { \GetExerciseParameter {solution-name} s }~
+             to~ the~ \XSIMmixedcase { \GetExerciseParameter {exercise-name} s} ,
+  English  = \XSIMmixedcase { \GetExerciseParameter {solution-name} s }~
+             to~ the~ \XSIMmixedcase { \GetExerciseParameter {exercise-name} s} ,
+  German   = \XSIMmixedcase { \GetExerciseParameter {solution-name} en }~
+             zu~ den~ \XSIMmixedcase { \GetExerciseParameter {exercise-name} en}
+}
+
+\DeclareExerciseTranslations {collection-heading} {
+  Fallback = \XSIMmixedcase { \GetExerciseParameter {exercise-name} s } ,
+  English  = \XSIMmixedcase { \GetExerciseParameter {exercise-name} s } ,
+  German   = \XSIMmixedcase { \GetExerciseParameter {exercise-name} en }
+}
+
+\DeclareExerciseTranslations {per-section-heading} {
+  Fallback = \XSIMmixedcase { \GetExerciseParameter {solution-name} s }~
+             to~ the~ \XSIMmixedcase { \GetExerciseParameter {exercise-name} s}~
+             of~ Section \nobreakspace \ExerciseSection ,
+  English  = \XSIMmixedcase { \GetExerciseParameter {solution-name} s }~
+             to~ the~ \XSIMmixedcase { \GetExerciseParameter {exercise-name} s}~
+             of~ Section \nobreakspace \ExerciseSection ,
+  German   = \XSIMmixedcase { \GetExerciseParameter {solution-name} en }~
+             zu~ den~ \XSIMmixedcase { \GetExerciseParameter {exercise-name} en}~
+             in~ Abschnitt \nobreakspace \ExerciseSection
+}
+
+\DeclareExerciseTranslations {per-chapter-heading} {
+  Fallback = \XSIMmixedcase { \GetExerciseParameter {solution-name} s }~
+             to~ the~ \XSIMmixedcase { \GetExerciseParameter {exercise-name} s}~
+             of~ Chapter \nobreakspace \ExerciseChapter ,
+  English  = \XSIMmixedcase { \GetExerciseParameter {solution-name} s }~
+             to~ the~ \XSIMmixedcase { \GetExerciseParameter {exercise-name} s}~
+             of~ Chapter \nobreakspace \ExerciseChapter ,
+  German   = \XSIMmixedcase { \GetExerciseParameter {solution-name} en }~
+             zu~ den~ \XSIMmixedcase { \GetExerciseParameter {exercise-name} en}~
+             in~ Kapitel \nobreakspace \ExerciseChapter
+}
+
+% ----------------------------------------------------------------------------
+\tex_endinput:D
diff --git a/Master/texmf-dist/tex/latex/xsim/xsim.environments.code.tex b/Master/texmf-dist/tex/latex/xsim/xsim.environments.code.tex
new file mode 100644
index 00000000000..43a46ab6146
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/xsim/xsim.environments.code.tex
@@ -0,0 +1,345 @@
+% ----------------------------------------------------------------------------
+% the XSIM package - environments module
+% 
+%   eXercise Sheets IMproved
+% 
+% ----------------------------------------------------------------------------
+% Clemens Niederberger
+% Web:    https://github.com/cgnieder/xsim
+% E-Mail: contact@mychemistry.eu
+% ----------------------------------------------------------------------------
+% Copyright 2017 Clemens Niederberger
+% 
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+% 
+% This work has the LPPL maintenance status `maintained'.
+% 
+% The Current Maintainer of this work is Clemens Niederberger.
+% ----------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% ----------------------------------------------------------------------------
+\XSIMmodule{environments}{generic code for exercise and solution environments}
+
+\xsim_load_modules:n {templates,verbwrite}
+
+\tl_new:N   \l__xsim_file_name_signature_tl
+\tl_new:N   \l__xsim_file_path_tl
+\tl_new:N   \l__xsim_file_path_and_name_tl
+\tl_new:N   \l__xsim_file_name_tl
+\bool_new:N \l__xsim_options_given_bool
+\bool_new:N \l__xsim_insert_mode_bool
+
+% ----------------------------------------------------------------------------
+
+\keys_define:nn {xsim}
+  { path .tl_set:N = \l__xsim_file_path_tl }
+
+% ----------------------------------------------------------------------------
+
+\tl_const:Nn \c__xsim_comment_line_tl { \c__xsim_percent_char_tl }
+\tl_const:Nn \c__xsim_comment_line_fill_tl { \prg_replicate:nn {72} {-} }
+\tl_const:Nn \c__xsim_comment_line_indent_tl { \c_space_tl \c_space_tl }
+
+\cs_new:Npn \__xsim_comment_line_and_feed:n #1
+  { \__xsim_comment_line:n {#1} ^^J }
+
+\cs_new:Npn \__xsim_comment_line:n #1
+  {
+    \c__xsim_comment_line_tl
+    \tl_if_blank:nF {#1} { \c_space_tl }
+    #1
+  }
+
+\cs_new:Npn \__xsim_two_digits:n #1
+  { \int_compare:nT { #1 < 10 } {0} \int_eval:n {#1} }
+  
+% #1: type
+% #2: id
+% #3: exercise|solution
+\cs_new_protected:Npn \__xsim_set_file_signature:nnn #1#2#3
+  { \tl_set:Nn \l__xsim_file_name_signature_tl {#1-#2-#3} }
+\cs_generate_variant:Nn \__xsim_set_file_signature:nnn {nx,nV}
+
+\tl_set:Nn \l__xsim_file_name_tl
+  { \c_sys_jobname_str - \l__xsim_file_name_signature_tl -body.tex }
+
+\tl_set:Nn \l__xsim_file_path_and_name_tl
+  {
+    \tl_if_blank:VF \l__xsim_file_path_tl
+      { \l__xsim_file_path_tl / }
+    \l__xsim_file_name_tl
+  }
+
+% #1: type
+% #2: id
+% #3: exercise|solution
+% #4: file name
+% #5: path
+\cs_new_protected:Npn \__xsim_file_info:nnnnn #1#2#3#4#5
+  {
+    \tl_set:Nn \l_xsim_file_begin_tl
+      {
+        \__xsim_comment_line_and_feed:n { \c__xsim_comment_line_fill_tl }
+        \__xsim_comment_line_and_feed:n {file~ `#4'}
+        \tl_if_blank:nF {#5}
+          {
+            \__xsim_comment_line_and_feed:n
+              { \c__xsim_comment_line_indent_tl in~ folder~ `#5/'}
+          }
+        \__xsim_comment_line_and_feed:n {}
+        \__xsim_comment_line_and_feed:n
+          {
+            \c__xsim_comment_line_indent_tl
+            \c__xsim_comment_line_indent_tl
+            #3~ of~ type~ `#1'~ with~ id~ `#2'
+          }
+        \__xsim_comment_line_and_feed:n {}
+        \__xsim_comment_line_and_feed:n
+          {generated~ by~ the~ `\@currenvir'~ environment~ of~ the}
+        \__xsim_comment_line_and_feed:n
+          {
+            \c__xsim_comment_line_indent_tl
+            `xsim'~ package~ v \c_xsim_version_tl
+            \c_space_tl (\c_xsim_date_tl)
+          }
+        \__xsim_comment_line_and_feed:n
+          {
+            from~ source~ `\c_sys_jobname_str'~ on~
+            \int_use:N \c_sys_year_int /
+            \__xsim_two_digits:n { \c_sys_month_int } /
+            \__xsim_two_digits:n { \c_sys_day_int } ~
+            \msg_line_context:
+          }
+        \__xsim_comment_line:n { \c__xsim_comment_line_fill_tl }
+      }
+  }
+\cs_generate_variant:Nn \__xsim_file_info:nnnnn {nnnVV}
+
+% ----------------------------------------------------------------------------
+
+% #1: type
+% #2: id
+% #3: exercise|solution
+\cs_new_protected:Npn \xsim_save_environment_body:nnn #1#2#3
+  {
+    \xsim_verbose:n
+      { Starting~ to~ write~ #3~ environment~ type~ `#1'~ id~ `#2' }
+    \__xsim_set_file_signature:nnn {#1} {#2} {#3}
+    \__xsim_file_info:nnnVV {#1} {#2} {#3}
+      \l__xsim_file_name_tl
+      \l__xsim_file_path_tl
+    \int_zero:N \l_xsim_line_gobble_int
+    \xsim_file_write_start:nV
+      { \l__xsim_options_given_bool }
+      \l__xsim_file_path_and_name_tl
+  }
+
+\cs_new_protected:Npn \xsim_save_environment_body_end:
+  { \xsim_file_write_stop: }
+
+% ----------------------------------------------------------------------------
+% #1: type
+% #2: exercise|solution
+% #3: hook
+\cs_new_protected:Npn \xsim_new_hook:nnn #1#2#3
+  {
+    \xsim_verbose:n { Defining~ new~ #1~ (#2)~ hook~ `#3' }
+    \tl_new:c {l__xsim_#1_#2_#3_hook_tl}
+    \keys_define:nx {xsim}
+      {
+        \xsim_get_parameter:nn {#1} {#2-env}/#3-hook .tl_set:N =
+          \exp_not:c {l__xsim_#1_#2_#3_hook_tl}
+      }
+  }
+
+% #1: type
+% #2: exercise|solution
+% #3: hook
+\cs_new:Npn \xsim_use_hook:nnn #1#2#3
+  { \exp_not:v {l__xsim_#1_#2_#3_hook_tl} }
+
+% #1: type
+% #2: exercise|solution
+% #3: hook
+% #4: code
+\cs_new_protected:Npn \xsim_set_hook:nnnn #1#2#3#4
+  {
+    \xsim_verbose:n { Setting~ #1~ (#2)~ hook~ `#3' }
+    \tl_set:cn {l__xsim_#1_#2_#3_hook_tl} {#4}
+  }
+
+% #1: type
+% #2: exercise|solution
+% #3: hook
+% #4: code
+\cs_new_protected:Npn \xsim_addto_hook:nnnn #1#2#3#4
+  {
+    \xsim_verbose:n { Adding~ to~ #1~ (#2)~ hook~ `#3' }
+    \tl_put_right:cn {l__xsim_#1_#2_#3_hook_tl} {#4}
+  }
+
+% ----------------------------------------------------------------------------
+
+% #1: type
+% #2: id
+% #3: exercise|solution
+\cs_new_protected:Npn \xsim_start_environment:nnn #1#2#3
+  { \xsim_save_environment_body:nnn {#1} {#2} {#3} }
+\cs_generate_variant:Nn \xsim_start_environment:nnn {nV}
+
+% #1: type
+% #2: id
+% #3: exercise|solution
+\cs_new_protected:Npn \xsim_stop_environment:nnn #1#2#3
+  {
+    \xsim_save_environment_body_end:
+    \xsim_if_print:nnnTF {#1} {#2} {#3}
+      { \xsim_typeset_environment:nnn {#1} {#2} {#3} }
+      { \xsim_use_hook:nnn {#1} {#3} {print-false} }
+  }
+\cs_generate_variant:Nn \xsim_stop_environment:nnn {nV}
+
+% #1: type
+% #2: id
+% #3: exercise|solution
+\cs_new_protected:Npn \xsim_typeset_environment:nnn #1#2#3
+  {
+    \xsim_verbose:n
+      { Typesetting~ #3~ environment~ type~ `#1'~ id~ `#2' }
+    \use:x
+      {
+        \exp_not:N \par
+        \xsim_use_hook:nnn {#1} {#3} {pre}
+        \xsim_use_template:nn
+          {begin}
+          { \xsim_get_parameter:nn {#1} {#3-template} }
+        \xsim_use_hook:nnn {#1} {#3} {begin}
+        \file_if_exist:nTF { \exp_not:V \l__xsim_file_path_and_name_tl }
+          { \file_input:n { \exp_not:V \l__xsim_file_path_and_name_tl } }
+          {
+            \xsim_verbose:n
+              { File~ `\l__xsim_file_path_and_name_tl'~ doesn't~ exist. }
+          }
+        \xsim_use_hook:nnn {#1} {#3} {end}
+        \xsim_use_template:nn
+          {end}
+          { \xsim_get_parameter:nn {#1} {#3-template} }
+        \xsim_use_hook:nnn {#1} {#3} {post}
+        \exp_not:N \par
+      }
+  }
+
+% #1: type
+% #2: id
+% #3: options
+% #4: exercise|solution
+\cs_new_protected:Npn \xsim_insert:nnnn #1#2#3#4
+  {
+    \__xsim_set_file_signature:nnn {#1} {#2} {#4}
+    \file_if_exist:VTF \l__xsim_file_path_and_name_tl
+      {
+        \xsim_verbose:n
+          { Inserting~ #4~ type~ `#1'~ id~ `#2'. }
+        \group_begin:
+          \xsim_insert_mode:
+          \use:c {xsim_start_#4:nn} {#1} {#3}
+          \tl_set:Nn \ExerciseType {#1}
+          \tl_set:Nn \ExerciseID {#2}
+          \str_if_eq:nnT {#4} {exercise}
+            {
+              \xsim_if_boolean_property:nnnF {#1} {#2} {used}
+                {
+                  \xsim_step_exercise_counter:nn {#1} {#2}
+                  \xsim_set_properties:nnx {#1} {#2}
+                    {
+                      page-value = \arabic{page} ,
+                      page = \thepage ,
+                      section-value = \arabic{section} ,
+                      section = \thesection
+                    }
+                }
+              \xsim_if_property_exist:nT {chapter}
+                {
+                  \xsim_set_properties:nnx {#1} {#2}
+                    {
+                      chapter-value = \arabic{chapter} ,
+                      chapter = \thechapter
+                    }
+                }
+              \xsim_set_properties:nnn {#1} {#2}
+                { print=true , used=true }
+            }
+          \use:x
+            {
+              \xsim_use_hook:nnn {#1} {#4} {pre}
+              \xsim_use_template:nn
+                {begin}
+                { \xsim_get_parameter:nn {#1} {#4-template} }
+              \xsim_use_hook:nnn {#1} {#4} {begin}
+              \file_input:n { \exp_not:V \l__xsim_file_path_and_name_tl }
+              \xsim_use_hook:nnn {#1} {#4} {end}
+              \xsim_use_template:nn
+                {end}
+                { \xsim_get_parameter:nn {#1} {#4-template} }
+              \xsim_use_hook:nnn {#1} {#4} {post}
+            }
+        \group_end:
+      }
+      {
+        \xsim_verbose:n
+          { File~ `\l__xsim_file_path_and_name_tl'~ doesn't~ exist. }
+      }
+  }
+\cs_generate_variant:Nn \xsim_insert:nnnn {nV,VV,nnnV}
+
+\prg_new_conditional:Npnn \xsim_if_insert_mode: {T,F,TF}
+  {
+    \bool_if:NTF \l__xsim_insert_mode_bool
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+\cs_new_protected:Npn \xsim_insert_mode:
+  { \bool_set_true:N \l__xsim_insert_mode_bool }
+
+% ----------------------------------------------------------------------------
+
+% #1: type
+% #2: exercise|solution
+\cs_new_protected:Npn \xsim_new_environment:nn #1#2
+  {
+    \xsim_verbose:n { Defining~ #2~ environment~ type~ `#1'. }
+    \xsim_new_hook:nnn {#1} {#2} {pre}
+    \xsim_new_hook:nnn {#1} {#2} {begin}
+    \xsim_new_hook:nnn {#1} {#2} {end}
+    \xsim_new_hook:nnn {#1} {#2} {post}
+    \xsim_new_hook:nnn {#1} {#2} {print-false}
+    \NewDocumentEnvironment
+      { \xsim_get_parameter:nn {#1} {#2-env} } {o}
+      {
+        \IfNoValueTF {##1}
+          {
+            \bool_set_false:N \l__xsim_options_given_bool
+            \use:c {xsim_start_#2:nn} {#1} {}
+          }
+          {
+            \bool_set_true:N \l__xsim_options_given_bool
+            \use:c {xsim_start_#2:nn} {#1} {##1}
+          }
+        \xsim_start_environment:nVn {#1} \g_xsim_exercise_id_tl {#2}
+      }
+      {
+        \xsim_stop_environment:nVn {#1} \g_xsim_exercise_id_tl {#2}
+        \use:c {xsim_stop_#2:n} {#1}
+      }
+  }
+
+% ----------------------------------------------------------------------------
+\tex_endinput:D
diff --git a/Master/texmf-dist/tex/latex/xsim/xsim.exercises.code.tex b/Master/texmf-dist/tex/latex/xsim/xsim.exercises.code.tex
new file mode 100644
index 00000000000..59434ec3071
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/xsim/xsim.exercises.code.tex
@@ -0,0 +1,515 @@
+% ----------------------------------------------------------------------------
+% the XSIM package - exercises module
+% 
+%   eXercise Sheets IMproved
+% 
+% ----------------------------------------------------------------------------
+% Clemens Niederberger
+% Web:    https://github.com/cgnieder/xsim
+% E-Mail: contact@mychemistry.eu
+% ----------------------------------------------------------------------------
+% Copyright 2017 Clemens Niederberger
+% 
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+% 
+% This work has the LPPL maintenance status `maintained'.
+% 
+% The Current Maintainer of this work is Clemens Niederberger.
+% ----------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% ----------------------------------------------------------------------------
+\XSIMmodule{exercises}{main exercises definitions}
+
+\xsim_load_modules:n
+  {
+    base, properties, environments, templates, solutions, tags, goals,
+    collections
+  }
+
+\seq_new:N  \l__xsim_parameters_seq
+\seq_new:N  \l__xsim_fixed_parameters_seq
+\seq_new:N  \l__xsim_mandatory_parameters_seq
+\prop_new:N \g__xsim_exercises_prop
+\int_gzero_new:N  \g_xsim_id_int
+\int_gzero_new:N  \g_xsim_max_id_int
+\tl_new:N   \l_xsim_current_id_tl
+\tl_new:N   \g_xsim_exercise_id_tl
+\tl_new:N   \ExerciseID
+\bool_new:N \l____xsim_print_bool
+
+% ----------------------------------------------------------------------------
+
+\msg_new:nnn {xsim} {parameter-fixed}
+  {
+    You~ tried~ to~ set~ parameter~ `#2'~ for~ type~ `#1'~ \msg_line_context:
+    . ~ However,~ parameter~ `#2'~ is~ a~ fixed~ parameter~ that~ already~
+    has~ been~ set~ for~ type~ `#1'.~ Its~ value~ can't~ be~ changed!
+  }
+
+\msg_new:nnn {xsim} {type-exists}
+  {
+    You~ try~ to~ define~ exercise~ type~ `#1'~ \msg_line_context: .~
+    However,~ the~ exercise~ type~ `#1'~ already~ exists.
+  }
+
+\msg_new:nnn {xsim} {mandatory-parameter}
+  {
+    You~ forget~ to~ set~ the~ mandatory~ parameter~ `#1'~ when~ defining~
+    exercise~ type~ `#2'.
+  }
+
+% ----------------------------------------------------------------------------
+
+\xsim_new_list:n {types}
+
+% #1: true|false (fixed parameter)
+% #2: true|false (mandatory parameter)
+% #3: parameter name
+\cs_new_protected:Npn \xsim_declare_parameter:nnn #1#2#3
+  {
+    \xsim_verbose:n { Declaring~ parameter~ `#3'. }
+    \xsim_if_parameter_exist:nF {#3}
+      {
+        \seq_put_right:Nn \l__xsim_parameters_seq {#3}
+        \bool_if:cT {c_#1_bool}
+          { \seq_put_right:Nn \l__xsim_fixed_parameters_seq {#3} }
+        \bool_if:cT {c_#2_bool}
+          { \seq_put_right:Nn \l__xsim_mandatory_parameters_seq {#3} }
+      }
+  }
+  
+\cs_new_protected:Npn \xsim_remove_parameter:n #1
+  {
+    \xsim_verbose:n { Removing~ parameter~ `#1'. }
+    \xsim_if_parameter_exist:nT {#1}
+      { \seq_remove_all:Nn \l__xsim_parameters_seq {#1} }
+  }
+
+\prg_new_conditional:Npnn \xsim_if_parameter_exist:n #1 {p,T,F,TF}
+  {
+    \seq_if_in:NnTF \l__xsim_parameters_seq {#1}
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+\cs_generate_variant:Nn \xsim_if_parameter_exist:nT {x}
+
+\prg_new_conditional:Npnn \xsim_if_parameter_fixed:n #1 {p,T,F,TF}
+  {
+    \seq_if_in:NnTF \l__xsim_fixed_parameters_seq {#1}
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+% #1: type
+% #2: csv list of parameters
+\cs_new_protected:Npn \xsim_set_parameters:nn #1#2
+  {
+    \clist_map_inline:nn {#2}
+      {
+        \seq_set_split:Nnx \l__xsim_tmpa_seq {=} { \tl_trim_spaces:n {##1} }
+        \xsim_set_parameter:nxx {#1}
+          { \seq_item:Nn \l__xsim_tmpa_seq {1} }
+          { \seq_item:Nn \l__xsim_tmpa_seq {2} }
+      }
+  }
+\cs_generate_variant:Nn \xsim_set_parameters:nn {nx}
+
+% #1: type
+\cs_new_protected:Npn \xsim_check_mandatory_parameters:n #1
+  {
+    \seq_map_inline:Nn \l__xsim_mandatory_parameters_seq
+      {
+        \xsim_if_parameter:nnF {#1} {##1}
+          { \msg_error:nnnn {xsim} {mandatory-parameter} {##1} {#1} }
+      }
+  }
+
+% #1: type
+\prg_new_conditional:Npnn \xsim_if_type:n #1 {p,T,F,TF}
+  {
+    \prop_if_exist:cTF {l__xsim_#1_type_parameters_prop}
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+% #1: type
+% #2: parameter
+% #3: value
+\cs_new_protected:Npn \xsim_set_parameter:nnn #1#2#3
+  {
+    \xsim_if_parameter_exist:nT {#2}
+      {
+        \xsim_if_parameter_fixed:nTF {#1}
+          {
+            \xsim_if_parameter:nnTF {#1} {#2}
+              {
+                \msg_warning:nnnn {xsim} {parameter-fixed} {#1} {#2}
+                \xsim_verbose:n
+                  {
+                    Not~ setting~ already~ set~ and~ fixed~ parameter~ `#2'~
+                    for~ type~ `#1'.
+                  }
+              }
+              {
+                \xsim_verbose:n
+                  { Setting~ parameter~ `#2'~ for~ type~ `#1'~ to~ `#3'. }
+                \prop_put:cnn {l__xsim_#1_type_parameters_prop} {#2} {#3}
+              }
+          }
+          {
+            \xsim_verbose:n
+              { Setting~ parameter~ `#2'~ for~ type~ `#1'~ to~ `#3'. }
+            \prop_put:cnn {l__xsim_#1_type_parameters_prop} {#2} {#3}
+          }
+      }
+  }
+\cs_generate_variant:Nn \xsim_set_parameter:nnn {nnx,nxx}
+
+% #1: type
+% #2: parameter
+\cs_new:Npn \xsim_get_parameter:nn #1#2
+  { \prop_item:cn {l__xsim_#1_type_parameters_prop} {#2} }
+\cs_generate_variant:Nn \xsim_get_parameter:nn {o}
+
+\prg_new_conditional:Npnn \xsim_if_parameter:nn #1#2 {p,T,F,TF}
+  {
+    \prop_if_in:cnTF {l__xsim_#1_type_parameters_prop} {#2}
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+% ----------------------------------------------------------------------------
+% inside the argument `#1' refers to the type
+\cs_new_protected:Npn \xsim_foreach_exercise_type:n #1
+  { \xsim_foreach_new_list_entry:nn {types} {#1} }
+
+\cs_new_protected:Npn \xsim_foreach_exercise_id:n #1
+  { \int_step_inline:nnnn {1} {1} { \g_xsim_max_id_int } {#1} }
+
+\cs_new:Npn \__xsim_loop_item:nnnnnn #1#2#3#4#5#6 {}
+\cs_generate_variant:Nn \__xsim_loop_item:nnnnnn {VVxxxx}
+
+% #1: type
+% #2: id
+% #3: boolean property
+\cs_new:Npn \__xsim_deliver_exercise_details:nnn #1#2#3
+  {
+    \xsim_if_in_list:nnT {#3} {#1-#2=={true}}
+      {
+        \tl_set_rescan:Nnx \l__xsim_tmpa_tl {} {#1}
+        \tl_set_rescan:Nnx \l__xsim_tmpb_tl {} {#2}
+        \__xsim_loop_item:VVxxxx
+          \l__xsim_tmpa_tl                                    % #1
+          \l__xsim_tmpb_tl                                    % #2
+          { \xsim_get_property:nnn {#1} {#2} {counter} }      % #3
+          { \xsim_get_property:nnn {#1} {#2} {subtitle} }     % #4
+          { \xsim_get_property:nnn {#1} {#2} {points} }       % #5
+          { \xsim_get_property:nnn {#1} {#2} {bonus-points} } % #6
+       }
+  }
+
+% #1: boolean property
+% #2: loop code
+\xsim_define_loop_macro:Nnn \xsim_foreach_exercise_type_id:nn
+  {nnnnnn}
+  {
+    \xsim_foreach_exercise_type:n
+      {
+        \xsim_foreach_exercise_id:n
+          { \__xsim_deliver_exercise_details:nnn {##1} {####1} {#1} }
+      }
+  }
+
+\xsim_define_loop_macro:Nnn \xsim_foreach_exercise_id_type:nn
+  {nnnnnn}
+  {
+    \xsim_foreach_exercise_id:n
+      {
+        \xsim_foreach_exercise_type:n
+          { \__xsim_deliver_exercise_details:nnn {####1} {##1} {#1} }
+      }
+  }
+
+\cs_new_protected:Npn \xsim_define_exercise_type_variables:n #1
+  {
+    \prop_new:c {l__xsim_#1_type_parameters_prop}
+    \bool_new:c {l__xsim_#1_solution_print_bool}
+    \bool_new:c {l__xsim_#1_exercise_print_bool}
+    \bool_new:c {l__xsim_#1_exercise_use_bool}
+  }
+
+\cs_new_protected:Npn \xsim_define_counters:n #1
+  {
+    \xsim_verbose:n { Defining~ counters~ for~ new~ exercise~ type~ `#1' }
+    \cs_if_exist:cF { c@ \xsim_get_parameter:nn {#1} {counter} }
+      { \newcounter { \xsim_get_parameter:nn {#1} {counter} } }
+    \cs_if_exist:cF { c@ \xsim_get_parameter:nn {#1} {solution-counter} }
+      { \newcounter { \xsim_get_parameter:nn {#1} {solution-counter} } }
+    \cs_if_exist:cF { c@ number of \xsim_get_parameter:nn {#1} {exercise-env} s }
+      { \newcounter { number of \xsim_get_parameter:nn {#1} {exercise-env} s } }
+  }
+
+% #1: type
+% #2: id
+\cs_new_protected:Npn \xsim_step_exercise_counter:nn #1#2
+  {
+    \refstepcounter { \xsim_get_parameter:nn {#1} {counter} }
+    \xsim_set_properties:nnx {#1} {#2}
+      {
+        counter = \use:c { the \xsim_get_parameter:nn {#1} {counter} } ,
+        counter-value = \arabic { \xsim_get_parameter:nn {#1} {counter} }
+      }
+  }
+\cs_generate_variant:Nn \xsim_step_exercise_counter:nn {nV}
+
+% #1: type
+\cs_new_protected:Npn \xsim_declare_exercise_type:nn #1#2
+  {
+    \xsim_if_type:nTF {#1}
+      { \msg_error:nnn {xsim} {type-exists} {#1} }
+      {
+        \xsim_verbose:n { Declaring~ new~ exercise~ type~ `#1'. }
+        \xsim_define_exercise_type_variables:n {#1}
+        \xsim_add_to_list:nn {types} {#1}
+        \xsim_set_parameters:nn {#1} {#2}
+        \xsim_set_parameter:nnx {#1} {number}
+          { number of \xsim_get_parameter:nn {#1} {exercise-env} s }
+        \xsim_check_mandatory_parameters:n {#1}
+        \xsim_if_parameter:nnF {#1} {counter}
+          {
+            \xsim_set_parameters:nx {#1}
+              { counter =  \xsim_get_parameter:nn {#1} {exercise-env} }
+          }
+        \xsim_if_parameter:nnF {#1} {solution-counter}
+          {
+            \xsim_set_parameters:nx {#1}
+              { solution-counter =  \xsim_get_parameter:nn {#1} {solution-env} }
+          }
+        \xsim_define_counters:n {#1}
+        \xsim_verbose:n { Defining~ options~ for~ new~ exercise~ type~ `#1' }
+        \keys_define:nx {xsim}
+          {
+            \xsim_get_parameter:nn {#1} {solution-env} / print
+              .bool_set:N = \exp_not:c {l__xsim_#1_solution_print_bool} ,
+            \xsim_get_parameter:nn {#1} {solution-env} / print
+              .initial:n  = false ,
+            \xsim_get_parameter:nn {#1} {exercise-env} / print
+              .bool_set:N = \exp_not:c {l__xsim_#1_exercise_print_bool} ,
+            \xsim_get_parameter:nn {#1} {exercise-env} / print
+              .initial:n  = true ,
+            \xsim_get_parameter:nn {#1} {exercise-env} / use
+              .bool_set:N = \exp_not:c {l__xsim_#1_exercise_use_bool} ,
+            \xsim_get_parameter:nn {#1} {exercise-env} / use
+              .initial:n  = true ,
+            \xsim_get_parameter:nn {#1} {exercise-env} / within .code:n =
+              \exp_not:N \@addtoreset { \xsim_get_parameter:nn {#1} {counter} } {####1},
+            \xsim_get_parameter:nn {#1} {exercise-env} / the-counter .code:n =
+              \cs_set:cpn {the \xsim_get_parameter:nn {#1} {counter} } {####1} ,
+            \xsim_get_parameter:nn {#1} {exercise-env} / template
+              .code:n = \xsim_set_parameter:nnn {#1} {exercise-template} {####1} ,
+            \xsim_get_parameter:nn {#1} {solution-env} / template
+              .code:n = \xsim_set_parameter:nnn {#1} {solution-template} {####1} ,
+            \xsim_get_parameter:nn {#1} {exercise-env} / name
+              .code:n = \xsim_set_parameter:nnn {#1} {exercise-name} {####1} ,
+            \xsim_get_parameter:nn {#1} {solution-env} / name
+              .code:n = \xsim_set_parameter:nnn {#1} {solution-name} {####1}
+          }
+        \xsim_new_environment:nn {#1} {exercise}
+        \xsim_new_environment:nn {#1} {solution}
+      }
+  }
+  
+% #1: type
+% #2: id
+\prg_new_conditional:Npnn \xsim_if_exercise_exists:nn #1#2 {T,F,TF}
+  {
+    \__xsim_set_file_signature:nnn {#1} {#2} {exercise}
+    \file_if_exist:VTF \l__xsim_file_path_and_name_tl
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+\cs_generate_variant:Nn \xsim_if_exercise_exists:nnT {VV}
+
+% #1: type
+% #2: options
+\cs_new_protected:Npn \xsim_start_exercise:nn #1#2
+  {
+    \xsim_if_insert_mode:F
+      {
+        \int_gincr:N \g_xsim_id_int
+        \int_compare:nF { \g_xsim_max_id_int > \g_xsim_id_int }
+          { \int_gset_eq:NN \g_xsim_max_id_int \g_xsim_id_int }
+        \xsim_set_properties:nxx {#1} { \int_use:N \g_xsim_id_int }
+          {
+            print = true ,
+            use = true ,
+            \exp_not:n {#2} ,
+            id = \int_use:N \g_xsim_id_int ,
+            section-value = \arabic{section} ,
+            section = \thesection ,
+            page-value = \arabic{page} ,
+            page = \thepage ,
+            used = false
+          }
+        \xsim_if_property_exist:nT {chapter}
+          {
+            \xsim_set_properties:nxx {#1} { \int_use:N \g_xsim_id_int }
+              {
+                chapter-value = \arabic{chapter} ,
+                chapter = \thechapter
+              }
+          }
+        \tl_gclear:N \g_xsim_exercise_id_tl
+        \xsim_gsave_property:nxnN {#1} { \int_use:N \g_xsim_id_int } {id}
+          \g_xsim_exercise_id_tl
+        \tl_gset_eq:NN \ExerciseID \g_xsim_exercise_id_tl
+        \tl_gset:Nn \ExerciseType {#1}
+        \xsim_verbose:x
+          {
+            Starting~ exercise~ type~ `#1' with~ id~
+            ` \g_xsim_exercise_id_tl '.
+          }
+        \xsim_exercise_if_use:nVTF {#1} \g_xsim_exercise_id_tl
+          {
+            \stepcounter { \xsim_get_parameter:nn {#1} {number} }
+            % don't step if in active collection:
+            \xsim_if_collections_active:TF
+              {
+                \xsim_set_property:nVnn {#1} \g_xsim_exercise_id_tl
+                  {print}
+                  {false}
+              }
+              {
+                \xsim_step_exercise_counter:nV {#1} \g_xsim_exercise_id_tl
+                \xsim_set_property:nVnn {#1} \g_xsim_exercise_id_tl
+                  {used}
+                  {true}
+              }
+            \xsim_set_property:nVnn {#1} \g_xsim_exercise_id_tl
+              {use}
+              {true}
+            \xsim_update_goals:nV {#1} \g_xsim_exercise_id_tl
+          }
+          {
+            \xsim_set_properties:nVn {#1} \g_xsim_exercise_id_tl
+              { use = false , print = false }
+          }
+        \xsim_update_collections:nV {#1} \g_xsim_exercise_id_tl
+      }
+  }
+
+\cs_new_protected:Npn \xsim_stop_exercise:n #1 {}
+
+% ----------------------------------------------------------------------------
+% #1: type
+% #2: id
+\prg_new_protected_conditional:Npnn \xsim_exercise_if_print:nn #1#2 {T,F,TF}
+  {
+    \xsim_if_boolean_property:nnnTF {#1} {#2} {print!}
+      { \prg_return_true: }
+      {
+        \bool_set_true:N \l____xsim_print_bool
+        \bool_if:cF {l__xsim_#1_exercise_print_bool}
+          { \bool_set_false:N \l____xsim_print_bool }
+        \xsim_if_tagged:nnF {#1} {#2}
+          { \bool_set_false:N \l____xsim_print_bool }
+        \xsim_if_boolean_property:nnnF {#1} {#2} {print}
+          { \bool_set_false:N \l____xsim_print_bool }
+        \bool_if:NTF \l____xsim_print_bool
+          { \prg_return_true: }
+          { \prg_return_false: }
+      }
+  }
+\cs_generate_variant:Nn \xsim_exercise_if_print:nnT  {nV}
+\cs_generate_variant:Nn \xsim_exercise_if_print:nnTF {nV}
+
+% #1: type
+% #2: id
+\prg_new_protected_conditional:Npnn \xsim_exercise_if_use:nn #1#2 {T,F,TF}
+  {
+    \xsim_if_boolean_property:nnnTF {#1} {#2} {use!}
+      { \prg_return_true: }
+      {
+        \xsim_exercise_if_print:nnTF {#1} {#2}
+          { \prg_return_true: }
+          {
+            \bool_if:cTF {l__xsim_#1_exercise_use_bool}
+              {
+                \xsim_if_boolean_property:nnnTF {#1} {#2} {use}
+                  {
+                    \xsim_if_tagged:nnTF {#1} {#2}
+                      { \prg_return_true: }
+                      { \prg_return_false: }
+                  }
+                  { \prg_return_false: }
+              }
+              { \prg_return_false: }
+          }
+          
+      }
+  }
+\cs_generate_variant:Nn \xsim_exercise_if_use:nnT  {nV}
+\cs_generate_variant:Nn \xsim_exercise_if_use:nnTF {nV}
+
+% #1: type
+% #2: id
+% #3: exercise|solution
+\prg_new_protected_conditional:Npnn \xsim_if_print:nnn #1#2#3 {T,F,TF}
+  {
+    \use:c {xsim_#3_if_print:nnTF} {#1} {#2}
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+% ----------------------------------------------------------------------------
+
+\xsim_new_aux_cs:cpn {total-number} #1
+  { \int_gset:Nn \g_xsim_max_id_int {#1} }
+
+\RequirePackage {etoolbox}
+
+\AtEndPreamble
+  {
+    \xsim_foreach_exercise_type:n
+      {
+        \tl_new:c { number of #1 s }
+        \tl_set:cn { number of #1 s } {0}
+        \xsim_new_aux_cs:cpn {#1} ##1
+          { \tl_gset:cn { number of #1 s } {##1} }
+      }
+  }
+
+\AtBeginDocument
+  {
+    \xsim_foreach_exercise_type:n
+      {
+        \xsim_write_to_aux:x
+          { \token_to_str:N \providecommand \token_to_str:N \numberof #1 s {} }
+      }
+  }
+
+\AtEndDocument
+  {
+    \xsim_if_clear_aux:T
+      {
+        \int_compare:nNnF { \g_xsim_max_id_int } = { \g_xsim_id_int }
+          { \xsim_empty_lists: }
+      }
+    \xsim_add_cs_to_aux:nn {total-number} { { \int_use:N \g_xsim_id_int } }
+    \xsim_foreach_exercise_type:n
+      {
+        \xsim_add_cs_to_aux:nn {#1}
+          { { \arabic { \xsim_get_parameter:nn {#1} {number} } } }
+      }
+    \xsim_update_list:n {types}
+  }
+
+% ----------------------------------------------------------------------------  
+\tex_endinput:D
diff --git a/Master/texmf-dist/tex/latex/xsim/xsim.goals.code.tex b/Master/texmf-dist/tex/latex/xsim/xsim.goals.code.tex
new file mode 100644
index 00000000000..8a881eb22ad
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/xsim/xsim.goals.code.tex
@@ -0,0 +1,307 @@
+% ----------------------------------------------------------------------------
+% the XSIM package - goals module
+% 
+%   eXercise Sheets IMproved
+% 
+% ----------------------------------------------------------------------------
+% Clemens Niederberger
+% Web:    https://github.com/cgnieder/xsim
+% E-Mail: contact@mychemistry.eu
+% ----------------------------------------------------------------------------
+% Copyright 2017 Clemens Niederberger
+% 
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+% 
+% This work has the LPPL maintenance status `maintained'.
+% 
+% The Current Maintainer of this work is Clemens Niederberger.
+% ----------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% ----------------------------------------------------------------------------
+\XSIMmodule{goals}{counting of points and bonus points}
+
+\xsim_load_modules:n {properties,exercises}
+
+\msg_new:nnn {xsim} {goal-unknown}
+  { The~ goal~ `#1'~ has~ never~ been~ declared~ \msg_line_context: }
+
+\seq_new:N \l__xsim_goals_seq
+\tl_new:N  \l_xism_grading_table_template_tl
+\tl_new:N  \l_xism_grading_table_exercise_type_tl
+
+% #1: name
+\cs_new_protected:Npn \xsim_declare_exercise_goal:n #1
+  {
+    \xsim_if_goal_exists:nF {#1}
+      {
+        \xsim_verbose:n { Declaring~ new~ goal~ `#1'. }
+        \xsim_declare_property:nnnn
+          { \c_false_bool }
+          { \c_false_bool }
+          { \c_false_bool }
+          {#1}
+        \seq_put_right:Nn \l__xsim_goals_seq {#1}
+        \fp_gzero_new:c {g__xsim_goal_#1_fp}
+        \fp_gzero_new:c {l__xsim_current_goal_#1_fp}
+        \fp_if_exist:cF {g__xsim_total_goal_#1_fp}
+          { \fp_new:c {g__xsim_total_goal_#1_fp} }
+        \fp_if_exist:cF {g__xsim_total_goal_recorded_#1_fp}
+          { \fp_new:c {g__xsim_total_goal_recorded_#1_fp} }
+        \AtBeginDocument
+          {
+            \xsim_foreach_exercise_type:n
+              {
+                \fp_gzero_new:c {g__xsim_##1_goal_#1_fp}
+                \fp_if_exist:cF {g__xsim_total_##1_goal_#1_fp}
+                  { \fp_new:c {g__xsim_total_##1_goal_#1_fp} }
+              }
+          }
+      }
+  }
+
+\prg_new_conditional:Npnn \xsim_if_goal_exists:n #1 {p,T,F,TF}
+  {
+    \seq_if_in:NnTF \l__xsim_goals_seq {#1}
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+% #1: exercise type
+% #2: id
+% #3: goal
+\cs_new_protected:Npn \xsim_update_goal:nnn #1#2#3
+  {
+    \xsim_if_goal_exists:nT {#3}
+      {
+        \fp_gadd:cn {g__xsim_goal_#3_fp}
+          { 0 \xsim_get_property:nnn {#1} {#2} {#3} }
+        \fp_gadd:cn {g__xsim_#1_goal_#3_fp}
+          { 0 \xsim_get_property:nnn {#1} {#2} {#3} }
+      }
+  }
+
+% #1: exercise type
+% #2: id
+\cs_new_protected:Npn \xsim_update_goals:nn #1#2
+  {
+    \xsim_foreach_goal:n
+      { \xsim_update_goal:nnn {#1} {#2} {##1} }
+  }
+\cs_generate_variant:Nn \xsim_update_goals:nn {nV}
+
+\cs_new_protected:Npn \xsim_foreach_goal:n #1
+  { \seq_map_inline:Nn \l__xsim_goals_seq {#1} }
+
+% #1: exercise type
+% #2: id
+% #3: goal
+% #4: value
+\cs_new_protected:Npn \xsim_addto_goal:nnnn #1#2#3#4
+  {
+    \xsim_if_goal_exists:nT {#3}
+      {
+        \xsim_verbose:n { Adding~ `#4'~ to~ `#3'~ goal~ of~ #1~ #2 }
+        \fp_gadd:cn {g__xsim_goal_#3_fp} {#4}
+        \fp_gadd:cn {g__xsim_#1_goal_#3_fp} {#4}
+        \fp_add:cn {l__xsim_current_goal_#3_fp} {#4}
+      }
+  }
+\cs_generate_variant:Nn \xsim_addto_goal:nnnn {xx,nVnx}
+
+% #1: exercise type
+% #2: id
+% #3: goal
+% #4: relation and value
+\prg_new_conditional:Npnn \xsim_if_goal_value:nnnn #1#2#3#4 {p,T,F,TF}
+  {
+    \fp_compare:nTF
+      { (0 \xsim_get_property:nnn {#1} {#2} {#3}) #4 }
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+\cs_generate_variant:Nn \xsim_if_goal_value:nnnnTF {xx}
+
+% ----------------------------------------------------------------------------
+% a function which can be used to modify how the numbers of a goal are
+% printed:
+\cs_new_protected:Npn \__xsim_print_goal:n #1 {#1}
+\cs_generate_variant:Nn \__xsim_print_goal:n {x}
+
+% #1: value
+% #2: value == 1
+% #3: value != 1
+\cs_new_protected:Npn \xsim_print_goal:nnn #1#2#3
+  {
+    \__xsim_print_goal:n { \fp_to_decimal:n {#1} }
+    \fp_compare:nTF { (#1) = 1 } {#2} {#3}
+  }
+
+% #1: exercise type
+% #2: goal
+% #3: sum == 1
+% #4: sum != 1
+\cs_new_protected:Npn \xsim_print_goal_sum:nnnn #1#2#3#4
+  { \xsim_print_goal:nnn { \use:c {g__xsim_total_#1_goal_#2_fp} } {#3} {#4} }
+
+% #1: goal
+% #2: sum == 1
+% #3: sum != 1
+\cs_new_protected:Npn \xsim_print_total_goal_sum:nnn #1#2#3
+  { \xsim_print_goal:nnn { \use:c {g__xsim_total_goal_#1_fp} } {#2} {#3} }
+
+% ----------------------------------------------------------------------------
+% the same as the last to functions but for a list of goals:
+
+% #1: fp variable to be set
+% #2: list of goals (separated with +)
+% #3: function to be applied to goal names
+\cs_new_protected:Npn \__xsim_exercise_goals_sum_aux:Nnn #1#2#3
+  {
+    \seq_set_split:Nnn \l__xsim_tmpa_seq {+} {#2}
+    \seq_set_map:NNn \l__xsim_tmpb_seq \l__xsim_tmpa_seq {#3}
+    \fp_set:Nn #1 { \seq_use:Nn \l__xsim_tmpb_seq {+} }
+  }
+
+% #1: fp variable
+% #2: exercise type
+% #3: list of goals (separated with +)
+\cs_new_protected:Npn \__xsim_exercise_goals_sum:Nnn #1#2#3
+  {
+    \__xsim_exercise_goals_sum_aux:Nnn #1 {#3}
+      { \exp_not:c {g__xsim_total_#2_goal_ \tl_trim_spaces:n {##1} _fp} }
+  }
+
+% #1: fp variable
+% #2: list of goals (separated with +)
+\cs_new_protected:Npn \__xsim_exercise_goals_sum:Nn #1#2
+  {
+    \__xsim_exercise_goals_sum_aux:Nnn #1 {#2}
+      { \exp_not:c {g__xsim_total_goal_ \tl_trim_spaces:n {##1} _fp} }
+  }
+
+% #1: exercise type
+% #2: list of goals (separated with +)
+% #3: sum == 1
+% #4: sum != 1
+\cs_new_protected:Npn \xsim_print_goals_sum:nnnn #1#2#3#4
+  {
+    \__xsim_exercise_goals_sum:Nnn \l__xsim_tmpa_fp {#1} {#2}
+    \xsim_print_goal:nnn { \l__xsim_tmpa_fp } {#3} {#4}
+  }
+
+% #1: list of goals (separated with +)
+% #2: sum == 1
+% #3: sum != 1
+\cs_new_protected:Npn \xsim_print_total_goals_sum:nnn #1#2#3
+  {
+    \__xsim_exercise_goals_sum:Nn \l__xsim_tmpa_fp {#1}
+    \xsim_print_goal:nnn { \l__xsim_tmpa_fp } {#2} {#3}
+  }
+
+% ----------------------------------------------------------------------------
+% #1: exercise type
+% #2: goal
+% #3: relation and value
+\prg_new_conditional:Npnn \xsim_if_goal_sum:nnn #1#2#3 {p,T,F,TF}
+  {
+    \fp_compare:nTF
+      { ( \use:c {g__xsim_total_#1_goal_#2_fp} ) #3 }
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+% #1: exercise type
+% #2: list of goals (separated with +)
+% #3: relation and value
+\prg_new_protected_conditional:Npnn \xsim_if_goals_sum:nnn #1#2#3 {T,F,TF}
+  {
+    \__xsim_exercise_goals_sum:Nnn \l__xsim_tmpa_fp {#1} {#2}
+    \fp_compare:nTF
+      { ( \l__xsim_tmpa_fp ) #3 }
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+% #1: goal
+% #2: relation and value
+\prg_new_conditional:Npnn \xsim_if_total_goal_sum:nn #1#2 {p,T,F,TF}
+  {
+    \fp_compare:nTF
+      { ( \use:c {g__xsim_total_goal_#1_fp} ) #2 }
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+% #1: list of goals (separated with +)
+% #2: relation and value
+\prg_new_protected_conditional:Npnn \xsim_if_total_goals_sum:nn #1#2 {T,F,TF}
+  {
+    \__xsim_exercise_goals_sum:Nn \l__xsim_tmpa_fp {#1}
+    \fp_compare:nTF
+      { ( \l__xsim_tmpa_fp ) #2 }
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+% ----------------------------------------------------------------------------
+% #1: exercise type
+% #2: goal
+% #3: value
+\xsim_new_aux_cs:cpn {goal} #1#2#3
+  { \fp_gset:cn {g__xsim_total_#1_goal_#2_fp} {#3} }
+
+% #1: goal
+% #2: value
+\xsim_new_aux_cs:cpn {totalgoal} #1#2
+  { \fp_gset:cn {g__xsim_total_goal_#1_fp} {#2} }
+
+\AtBeginDocument
+  {
+    \seq_map_inline:Nn \l__xsim_goals_seq
+      {
+        \fp_gset_eq:cc
+          {g__xsim_total_goal_recorded_#1_fp}
+          {g__xsim_total_goal_#1_fp}
+      }
+  }
+  
+\AtEndDocument
+  {
+    \seq_map_inline:Nn \l__xsim_goals_seq
+      {
+        \xsim_foreach_exercise_type:n
+          {
+            \xsim_add_cs_to_aux:nn {goal}
+              { {##1} {#1} { \fp_to_decimal:c {g__xsim_##1_goal_#1_fp} } }
+          }
+        \tl_set:Nx \l__xsim_tmpa_tl
+          { \fp_to_decimal:c {g__xsim_total_goal_#1_fp} }
+        \tl_set:Nx \l__xsim_tmpb_tl
+          { \fp_to_decimal:c {g__xsim_total_goal_recorded_#1_fp} }
+        \tl_if_eq:NNF \l__xsim_tmpa_tl \l__xsim_tmpb_tl { \xsim_rerun: }
+        \xsim_add_cs_to_aux:nn {totalgoal}
+          { {#1} { \fp_to_decimal:c {g__xsim_goal_#1_fp} } }
+      }
+  }
+
+% ----------------------------------------------------------------------------
+
+\keys_define:nn {xsim}
+  {
+    goal-print .code:n =
+      \cs_set_protected:Npn \__xsim_print_goal:n ##1 {#1} ,
+    grading-table/template .tl_set:N  = \l_xism_grading_table_template_tl ,
+    grading-table/template .initial:n = default ,
+    grading-table/type     .tl_set:N  = \l_xism_grading_table_exercise_type_tl ,
+    grading-table/type     .initial:n =
+  }
+
+% ----------------------------------------------------------------------------
+\tex_endinput:D
diff --git a/Master/texmf-dist/tex/latex/xsim/xsim.grades.code.tex b/Master/texmf-dist/tex/latex/xsim/xsim.grades.code.tex
new file mode 100644
index 00000000000..0fe0d162db5
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/xsim/xsim.grades.code.tex
@@ -0,0 +1,153 @@
+% ----------------------------------------------------------------------------
+% the XSIM package - grades module
+% 
+%   eXercise Sheets IMproved
+% 
+% ----------------------------------------------------------------------------
+% Clemens Niederberger
+% Web:    https://github.com/cgnieder/xsim
+% E-Mail: contact@mychemistry.eu
+% ----------------------------------------------------------------------------
+% Copyright 2017 Clemens Niederberger
+% 
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+% 
+% This work has the LPPL maintenance status `maintained'.
+% 
+% The Current Maintainer of this work is Clemens Niederberger.
+% ----------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% ----------------------------------------------------------------------------
+\XSIMmodule{grades}{distribute goal sums to grades}
+
+\xsim_load_modules:n {goals}
+
+\msg_new:nnn {xsim} {grade-unknown}
+  { The~ grade~ `#1'~ has~ never~ been~ declared~ \msg_line_context: }
+
+\bool_new:N \l__xsim_grades_half_bool
+\fp_new:N   \l__xsim_grade_round_fp
+\fp_zero:N  \l__xsim_grade_round_fp
+\prop_new:N \l__xsim_relative_grades_prop
+\tl_new:N   \l__xsim_grade_split_tl
+
+\cs_new:Npn \__xsim_fp_round_to_half:n #1
+  { round( 2*(#1),0)/2 }
+
+\cs_new:Npn \__xsim_grades_round:n #1
+  { round ( #1 , \l__xsim_grade_round_fp ) }
+
+% #1: factor
+% #2: goal sum
+\cs_new:Npn \__xsim_grade_rounded:nn #1#2
+  {
+    \bool_if:NTF \l__xsim_grades_half_bool
+      { \__xsim_fp_round_to_half:n }
+      { \__xsim_grades_round:n }
+    { (#1) * (#2) }
+  }
+
+\cs_new_protected:Npn \xsim_declare_relative_grades:n #1
+  {
+    \seq_set_split:NVn \l__xsim_tmpa_seq \l__xsim_grade_split_tl {#1}
+    \seq_map_inline:Nn \l__xsim_tmpa_seq
+      { \__xsim_declare_relative_grade:w ##1 \q_stop }
+    \xsim_verbose:n {Declaring~ relative~ grade~ distribution}
+  }
+
+\cs_new_protected:Npn \__xsim_declare_relative_grade:w #1 = #2 \q_stop
+  {
+    \tl_set:Nx \l__xsim_tmpa_tl { \tl_trim_spaces:n {#1} }
+    \tl_set:Nx \l__xsim_tmpb_tl { \tl_trim_spaces:n {#2} }
+    \prop_put:NVV \l__xsim_relative_grades_prop
+      \l__xsim_tmpa_tl
+      \l__xsim_tmpb_tl
+  }
+
+% #1: grade
+% #2: sum of points
+% #3: code after grade requirement if == 1
+% #4: code after grade requirement if != 1
+\cs_new_protected:Npn \xsim_get_grade:nnnn #1#2#3#4
+  {
+    \prop_get:NnNTF \l__xsim_relative_grades_prop {#1} \l__xsim_tmpa_tl
+      {
+        \xsim_print_goal:nnn
+          {
+            min(
+              \__xsim_grade_rounded:nn
+                { \l__xsim_tmpa_tl }
+                {#2} ,
+              #2
+            )
+          }
+          {#3}
+          {#4}
+      }
+      { \msg_error:nnn {xsim} {grade-unknown} {#1} }
+  }
+
+% #1: grade
+% #2: goal
+% #3: code after grade requirement if == 1
+% #4: code after grade requirement if != 1
+\cs_new_protected:Npn \xsim_get_grade_goal:nnnn #1#2#3#4
+  {
+    \xsim_if_goal_exists:nTF {#2}
+      {
+        \xsim_get_grade:nnnn
+          {#1}
+          { \use:c {g__xsim_total_goal_#2_fp} }
+          {#3}
+          {#4}
+      }
+      { \msg_error:nnn {xsim} {goal-unknown} {#2} }
+  }
+
+% #1: grade
+% #2: goal list (separated with +)
+% #3: code after grade requirement if == 1
+% #4: code after grade requirement if != 1
+\cs_new_protected:Npn \xsim_get_grade_requirement:nnnn #1#2#3#4
+  {
+    \seq_set_split:Nnn \l__xsim_tmpa_seq {+} {#2}
+    \fp_zero:N \l__xsim_tmpa_fp
+    \seq_map_inline:Nn \l__xsim_tmpa_seq
+      {
+        \fp_add:Nn \l__xsim_tmpa_fp
+          { \use:c {g__xsim_total_goal_\tl_trim_spaces:n {##1} _fp} }
+      }
+    \xsim_get_grade:nnnn {#1} { \l__xsim_tmpa_fp } {#3} {#4}
+  }
+
+% #1: grade
+% #2: code after grade requirement if == 1
+% #3: code after grade requirement if != 1
+\cs_new_protected:Npn \xsim_get_absolute_grade_requirement:nnn #1#2#3
+  {
+    \fp_zero:N \l__xsim_tmpa_fp
+    \xsim_foreach_goal:n
+      {
+        \fp_add:Nn \l__xsim_tmpa_fp
+          { \use:c {g__xsim_total_goal_##1_fp} }
+      }
+    \xsim_get_grade:nnnn {#1} { \l__xsim_tmpa_fp } {#2} {#3}
+  }
+
+\keys_define:nn {xsim/grades}
+  {
+    round .fp_set:N   = \l__xsim_grade_round_fp ,
+    half  .bool_set:N = \l__xsim_grades_half_bool ,
+    split .tl_set:N   = \l__xsim_grade_split_tl ,
+    split .initial:n  = {,}
+  }
+
+% ----------------------------------------------------------------------------
+\tex_endinput:D
diff --git a/Master/texmf-dist/tex/latex/xsim/xsim.interface.code.tex b/Master/texmf-dist/tex/latex/xsim/xsim.interface.code.tex
new file mode 100644
index 00000000000..b1006f49356
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/xsim/xsim.interface.code.tex
@@ -0,0 +1,565 @@
+% ----------------------------------------------------------------------------
+% the XSIM package - interface module
+% 
+%   eXercise Sheets IMproved
+% 
+% ----------------------------------------------------------------------------
+% Clemens Niederberger
+% Web:    https://github.com/cgnieder/xsim
+% E-Mail: contact@mychemistry.eu
+% ----------------------------------------------------------------------------
+% Copyright 2017 Clemens Niederberger
+% 
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+% 
+% This work has the LPPL maintenance status `maintained'.
+% 
+% The Current Maintainer of this work is Clemens Niederberger.
+% ----------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% ----------------------------------------------------------------------------
+\XSIMmodule{interface}{user interface}
+
+\NewDocumentCommand \DeclareExerciseEnvironmentTemplate {m+m+m}
+  { \xsim_declare_environment_template:nnn {#1} {#2} {#3} }
+\@onlypreamble \DeclareExerciseEnvironmentTemplate
+
+\NewDocumentCommand \DeclareExerciseHeadingTemplate {m+m}
+  { \xsim_declare_heading_template:nn {#1} {#2} }
+\@onlypreamble \DeclareExerciseHeadingTemplate
+
+\NewDocumentCommand \DeclareExerciseTableTemplate {m+m}
+  { \xsim_declare_table_template:nn {#1} {#2} }
+\@onlypreamble \DeclareExerciseTableTemplate
+
+\NewDocumentCommand \UseExerciseTemplate {mm}
+  { \xsim_use_template:nn {#1} {#2} }
+
+% ----------------------------------------------------------------------------
+
+\NewDocumentCommand \DeclareExerciseType {mm}
+  { \xsim_declare_exercise_type:nn {#1} {#2} }
+\@onlypreamble \DeclareExerciseType
+
+\NewExpandableDocumentCommand \numberofusedexercises {}
+  { \int_use:N \g_xsim_max_id_int }
+
+% ----------------------------------------------------------------------------
+
+\NewExpandableDocumentCommand \IfInsideSolutionTF {+m+m}
+  { \xsim_if_inside_solution:TF {#1} {#2} }
+
+\NewExpandableDocumentCommand \IfInsideSolutionT {+m}
+  { \IfInsideSolutionTF {#1} {} }
+
+\NewExpandableDocumentCommand \IfInsideSolutionF {+m}
+  { \IfInsideSolutionTF {} {#1} }
+
+\NewExpandableDocumentCommand \IfSolutionPrintTF {+m+m}
+  { \xsim_if_solution_print:nTF {\ExerciseType} {#1} {#2} }
+
+\NewExpandableDocumentCommand \IfSolutionPrintT {+m}
+  { \IfSolutionPrintTF {#1} {} }
+
+\NewExpandableDocumentCommand \IfSolutionPrintF {+m}
+  { \IfSolutionPrintTF {} {#1} }
+
+% ----------------------------------------------------------------------------
+
+\NewDocumentCommand \DeclareExerciseProperty {t!st-m}
+  {
+    \IfBooleanTF {#2}
+      {
+        \IfBooleanTF {#3}
+          {
+            \xsim_declare_property:nnnn
+              { \c_false_bool }
+              { \c_true_bool }
+              { \c_true_bool }
+              {#4}
+          }
+          {
+            \xsim_declare_property:nnnn
+              { \c_false_bool }
+              { \c_true_bool }
+              { \c_false_bool }
+              {#4}
+          }
+      }
+      {
+        \IfBooleanTF {#1}
+          {
+            \IfBooleanTF {#3}
+              {
+                \xsim_declare_property:nnnn
+                  { \c_true_bool }
+                  { \c_false_bool }
+                  { \c_true_bool }
+                  {#4}
+              }
+              {
+                \xsim_declare_property:nnnn
+                  { \c_true_bool }
+                  { \c_false_bool }
+                  { \c_false_bool }
+                  {#4}
+              }
+          }
+          {
+            \IfBooleanTF {#3}
+              {
+                \xsim_declare_property:nnnn
+                  { \c_false_bool }
+                  { \c_false_bool }
+                  { \c_true_bool }
+                  {#4}
+              }
+              {
+                \xsim_declare_property:nnnn
+                  { \c_false_bool }
+                  { \c_false_bool }
+                  { \c_false_bool }
+                  {#4}
+              }
+          }
+      }
+  }
+\@onlypreamble \DeclareExerciseProperty
+
+\NewDocumentCommand \DeclareExercisePropertyAlias {mm}
+  { \xsim_make_property_alias:nn {#1} {#2} }
+\@onlypreamble \DeclareExercisePropertyAlias
+
+\NewDocumentCommand \SetExerciseProperty {mmm+m}
+  { \xsim_set_property:nnnn {#1} {#2} {#3} {#4} }
+
+\NewExpandableDocumentCommand \IfExercisePropertyExistTF {+m+m+m}
+  { \xsim_if_property_exist:nTF {#1} {#2} {#3} }
+
+\NewExpandableDocumentCommand \IfExercisePropertyExistT {+m+m}
+  { \IfExercisePropertyExistTF {#1} {#2} {} }
+
+\NewExpandableDocumentCommand \IfExercisePropertyExistF {+m+m}
+  { \IfExercisePropertyExistTF {#1} {} {#2} }
+
+\NewDocumentCommand \IfExercisePropertySetTF {m+m+m}
+  { \xsim_if_property_set:xxnTF {\ExerciseType} {\ExerciseID} {#1} {#2} {#3} }
+
+\NewDocumentCommand \IfExercisePropertySetT {m+m}
+  { \IfExercisePropertySetTF {#1} {#2} {} }
+
+\NewDocumentCommand \IfExercisePropertySetF {m+m}
+  { \IfExercisePropertySetTF {#1} {} {#2} }
+
+\NewExpandableDocumentCommand \GetExerciseProperty {m}
+  { \xsim_get_property:oon {\ExerciseType} {\ExerciseID} {#1} }
+
+\NewExpandableDocumentCommand \GetExerciseAliasProperty {m}
+  {
+    \xsim_get_property:oof
+      {\ExerciseType}
+      {\ExerciseID}
+      { \xsim_property_alias:n {#1} }
+  }
+
+\NewDocumentCommand \GetExercisePropertyTF {m+m+m}
+  {
+    \xsim_get_property_if_set:oonTF {\ExerciseType} {\ExerciseID} {#1}
+      {#2}
+      {#3}
+  }
+
+\NewDocumentCommand \GetExercisePropertyT {m+m}
+  { \GetExercisePropertyTF {#1} {#2} {} }
+\NewDocumentCommand \GetExercisePropertyF {m+m+m}
+  { \GetExercisePropertyTF {#1} {} {#2} }
+
+\NewExpandableDocumentCommand \GetExerciseIdForProperty {mm}
+  { \xsim_get_id_for_property:nn {#1} {#2} }
+
+\NewExpandableDocumentCommand \GetExerciseTypeForProperty {mm}
+  { \xsim_get_type_for_property:nn {#1} {#2} }
+
+\NewExpandableDocumentCommand \IfExerciseBooleanPropertyTF {+m+m+m}
+  {
+    \xsim_if_boolean_property:oonTF {\ExerciseType} {\ExerciseID} {#1}
+      {#2}
+      {#3}
+  }
+
+\NewExpandableDocumentCommand \IfExerciseBooleanPropertyT {+m+m}
+  { \IfExerciseBooleanPropertyTF {#1} {#2} {} }
+\NewExpandableDocumentCommand \IfExerciseBooleanPropertyF {+m+m}
+  { \IfExerciseBooleanPropertyTF {#1} {} {#2} }
+
+\NewDocumentCommand \SaveExerciseProperty {mm}
+  { \xsim_save_property:xxnN {\ExerciseType} {\ExerciseID} {#1} #2 }
+
+\NewDocumentCommand \GlobalSaveExerciseProperty {mm}
+  { \xsim_gsave_property:xxnN {\ExerciseType} {\ExerciseID} {#1} #2 }
+
+% ----------------------------------------------------------------------------
+
+\NewDocumentCommand \DeclareExerciseParameter {st!m}
+   {
+     \IfBooleanTF {#1}
+       {
+         \IfBooleanTF {#2}
+           { \xsim_declare_parameter:nnn {true} {true} {#3} }
+           { \xsim_declare_parameter:nnn {true} {false} {#3} }
+       }
+       {
+         \IfBooleanTF {#2}
+           { \xsim_declare_parameter:nnn {false} {true} {#3} }
+           { \xsim_declare_parameter:nnn {false} {false} {#3} }
+       }
+   }
+
+\NewExpandableDocumentCommand \GetExerciseParameter {m}
+  { \xsim_get_parameter:on {\ExerciseType} {#1} }
+
+\NewDocumentCommand \SetExerciseParameter {mmm}
+  { \xsim_set_parameter:nnn {#1} {#2} {#3} }
+
+\NewDocumentCommand \SetExerciseParameters {mm}
+  { \xsim_set_parameters:nn {#1} {#2} }
+
+\NewExpandableDocumentCommand \GetExerciseName {}
+  {
+    \IfInsideSolutionTF
+      { \GetExerciseParameter {solution-name} }
+      { \GetExerciseParameter {exercise-name} }
+  }
+
+% ----------------------------------------------------------------------------
+
+\NewDocumentCommand \ExercisePropertyIfSetTF {mmm+m+m}
+  { \xsim_if_property_set:nnnTF {#1} {#2} {#3} {#4} {#5} }
+
+\NewDocumentCommand \ExercisePropertyIfSetT {mmm+m}
+  { \ExercisePropertyIfSetTF {#1} {#2} {#3} {#4} {} }
+
+\NewDocumentCommand \ExercisePropertyIfSetF {mmm+m}
+  { \ExercisePropertyIfSetTF {#1} {#2} {#3} {} {#4} }
+
+\NewExpandableDocumentCommand \ExercisePropertyGet {mmm}
+  { \xsim_get_property:nnn {#1} {#2} {#3} }
+
+\NewExpandableDocumentCommand \ExercisePropertyGetAlias {mm}
+  { \xsim_get_property:nnf {#1} {#2} { \xsim_property_alias:n {#1} } }
+
+\NewDocumentCommand \ExercisePropertySave {mmmm}
+  { \xsim_save_property:nnnN {#1} {#2} {#3} #4 }
+
+\NewDocumentCommand \ExercisePropertyGlobalSave {mmmm}
+  { \xsim_gsave_property:nnnN {#1} {#2} {#3} #4 }
+
+\NewExpandableDocumentCommand \ExerciseParameterGet {mm}
+  { \xsim_get_parameter:nn {#1} {#2} }
+
+% ----------------------------------------------------------------------------
+
+\NewExpandableDocumentCommand \XSIMtranslate {m}
+  { \xsim_translate:n {#1} }
+
+\NewDocumentCommand \XSIMexpandcode {+m}
+  { \use:x {#1} }
+
+\NewExpandableDocumentCommand \XSIMmixedcase {m}
+  { \tl_mixed_case:f {#1} }
+
+\NewDocumentCommand \XSIMputright {mm}
+  { \tl_put_right:Nn #1 {#2} }
+
+\NewExpandableDocumentCommand \XSIMifeqTF {+m+m+m+m}
+  { \tl_if_eq:ffTF {#1} {#2} {#3} {#4} }
+
+\NewExpandableDocumentCommand \XSIMifeqT {+m+m+m}
+  { \XSIMifeqTF {#1} {#2} {#3} {} }
+
+\NewExpandableDocumentCommand \XSIMifeqF {+m+m+m}
+  { \XSIMifeqTF {#1} {#2} {} {#3} }
+
+\NewExpandableDocumentCommand \XSIMifblankTF {+m+m+m}
+  { \tl_if_blank:fTF {#1} {#2} {#3} }
+
+\NewExpandableDocumentCommand \XSIMifblankT {+m+m}
+  { \XSIMifblankTF {#1} {#2} {} }
+
+\NewExpandableDocumentCommand \XSIMifblankF {+m+m}
+  { \XSIMifblankTF {#1} {} {#2} {} }
+
+% ----------------------------------------------------------------------------
+
+\NewDocumentCommand \DeclareExerciseGoal {m}
+  { \xsim_declare_exercise_goal:n {#1} }
+\@onlypreamble \DeclareExerciseGoal
+
+\NewDocumentCommand \IfExerciseGoalTF {mm+m+m}
+  {
+    \xsim_if_goal_value:xxnnTF
+      {\ExerciseType} {\ExerciseID} {#1}
+      {#2}
+      {#3} {#4}
+  }
+
+\NewDocumentCommand \IfExerciseGoalT {mm+m}
+  { \IfExerciseGoalTF {#1} {#2} {#3} {} }
+
+\NewDocumentCommand \IfExerciseGoalF {mm+m}
+  { \IfExerciseGoalTF {#1} {#2} {} {#3} }
+
+\NewDocumentCommand \IfExerciseGoalSingularTF {mmm}
+  { \IfExerciseGoalTF {#1} {=1} {#2} {#3} }
+
+\NewDocumentCommand \IfExerciseGoalSingularT {mm}
+  { \IfExerciseGoalT {#1} {=1} {#2} }
+
+\NewDocumentCommand \IfExerciseGoalSingularF {mm}
+  { \IfExerciseGoalF {#1} {=1} {#2} }
+
+\NewDocumentCommand \IfExerciseTypeGoalsSumTF {mmm+m+m}
+  { \xsim_if_goals_sum:nnnTF {#1} {#2} {#3} {#4} {#5} }
+
+\NewDocumentCommand \IfExerciseTypeGoalsSumT {mmm+m}
+  { \IfExerciseTypeGoalsSumTF {#1} {#2} {#3} {#4} {} }
+
+\NewDocumentCommand \IfExerciseTypeGoalsSumF {mmm+m}
+  { \IfExerciseTypeGoalsSumTF {#1} {#2} {#3} {} {#4} }
+
+\NewDocumentCommand \IfExerciseGoalsSumTF {mm+m+m}
+  { \xsim_if_total_goals_sum:nnTF {#1} {#2} {#3} {#4} }
+
+\NewDocumentCommand \IfExerciseGoalsSumT {mm+m}
+  { \IfExerciseGoalsSumTF {#1} {#2} {#3} {} }
+
+\NewDocumentCommand \IfExerciseGoalsSumF {mm+m}
+  { \IfExerciseGoalsSumTF {#1} {#2} {} {#3} }
+
+\NewDocumentCommand \TotalExerciseTypeGoal {mmmm}
+  { \xsim_print_goal_sum:nnnn {#1} {#2} {#3} {#4} }
+
+\NewDocumentCommand \TotalExerciseTypeGoals {mmmm}
+  { \xsim_print_goals_sum:nnnn {#1} {#2} {#3} {#4} }
+
+\NewDocumentCommand \TotalExerciseGoal {mmm}
+  { \xsim_print_total_goal_sum:nnn {#1} {#2} {#3} }
+
+\NewDocumentCommand \TotalExerciseGoals {mmm}
+  { \xsim_print_total_goals_sum:nnn {#1} {#2} {#3} }
+
+\NewDocumentCommand \AddtoExerciseTypeGoal {mmmm}
+  { \xsim_addto_goal:nnnn {#1} {#2} {#3} {#4} }
+
+\NewDocumentCommand \AddtoExerciseGoal {mm}
+  { \xsim_addto_goal:xxnn {\ExerciseType} {\ExerciseID} {#1} {#2} }
+
+\NewDocumentCommand \ExerciseGoalValuePrint {mmm}
+  { \xsim_print_goal:nnn {#1} {#2} {#3} }
+
+\NewDocumentCommand \AddtoExerciseTypeGoalPrint {mmmmmm}
+  {
+    \xsim_addto_goal:nnnn {#1} {#2} {#3} {#4}
+    \xsim_print_goal:nnn {#4} {#5} {#6}
+  }
+
+\NewDocumentCommand \AddtoExerciseGoalPrint {mmmm}
+  {
+    \xsim_addto_goal:xxnn {\ExerciseType} {\ExerciseID} {#1} {#2}
+    \xsim_print_goal:nnn {#2} {#3} {#4}
+  }
+
+% ----------------------------------------------------------------------------
+\NewDocumentCommand \DeclareGradeDistribution {m}
+  { \xsim_declare_relative_grades:n {#1} }
+
+\NewDocumentCommand \GetGradeRequirementForGoal {mmmm}
+  { \xsim_get_grade_goal:nnnn {#1} {#2} {#3} {#4} }
+
+\NewDocumentCommand \GetGradeRequirementForGoals {mmmm}
+  { \xsim_get_grade_requirement:nnnn {#1} {#2} {#3} {#4} }
+
+\NewDocumentCommand \GetGradeRequirement {mmm}
+  { \xsim_get_absolute_grade_requirement:nnn {#1} {#2} {#3} }
+
+% ----------------------------------------------------------------------------
+
+\NewDocumentCommand \DeclareExerciseTagging {m}
+  { \xsim_new_tag_type:n {#1} }
+\@onlypreamble \DeclareExerciseTagging
+
+\NewDocumentCommand \ForEachExerciseTag {m+m}
+  { \xsim_foreach_exercise_tag:oonn {\ExerciseType} {\ExerciseID} {#1} {#2} }
+
+\NewDocumentCommand \ListExerciseTags {mm}
+  { \xsim_exercise_tags_use:oonn {\ExerciseType} {\ExerciseID} {#1} {#2} }
+
+\NewDocumentCommand \UseExerciseTags {mmmm}
+  {
+    \xsim_exercise_tags_use:oonnnn
+      {\ExerciseType}
+      {\ExerciseID}
+      {#1}
+      {#2}
+      {#3}
+      {#4}
+  }
+
+% ----------------------------------------------------------------------------
+
+\NewDocumentCommand \ForEachPrintedExerciseByType {+m}
+  { \xsim_foreach_exercise_type_id:nn {print} {#1} }
+
+\NewDocumentCommand \ForEachPrintedExerciseByID {+m}
+  { \xsim_foreach_exercise_id_type:nn {print} {#1} }
+
+\NewDocumentCommand \ForEachUsedExerciseByType {+m}
+  { \xsim_foreach_exercise_type_id:nn {use} {#1} }
+
+\NewDocumentCommand \ForEachUsedExerciseByID {+m}
+  { \xsim_foreach_exercise_id_type:nn {use} {#1} }
+
+% ----------------------------------------------------------------------------
+
+\NewDocumentCommand \DeclareExerciseTranslations {mm}
+  { \xsim_declare_translations:nn {#1} {#2} }
+\@onlypreamble \DeclareExerciseTranslations
+  
+\NewDocumentCommand \DeclareExerciseTranslation {mmm}
+  { \xsim_declare_translation:nnn {#1} {#2} {#3} }
+\@onlypreamble \DeclareExerciseTranslation
+
+\NewDocumentCommand \ForEachExerciseTranslation {+m}
+  { \xsim_for_all_translations_do:n {#1} }
+
+% ----------------------------------------------------------------------------
+
+\NewDocumentCommand \DeclareExerciseCollection {m}
+  { \xsim_new_collection:n {#1} }
+\@onlypreamble \DeclareExerciseCollection
+
+\NewDocumentCommand \collectexercisestype {mm}
+  { \xsim_start_collection:nn {#1} {#2} }
+
+\NewDocumentCommand \collectexercises {m}
+  { \xsim_start_collection:n {#1} }
+
+\NewDocumentCommand \collectexercisesstop {m}
+  { \xsim_stop_collection:n {#1} }
+
+\NewDocumentCommand \printcollection {O{}m}
+  { \xsim_print_collection:nn {#1} {#2} }
+
+\NewDocumentCommand \printrandomexercises {O{}m}
+  {
+    \group_begin:
+      \keys_set:nn {xsim/random} {#1}
+      \xsim_print_random_list:VnV
+        \l_xsim_random_collection_tl
+        {#2}
+        \l_xsim_random_exclude_list_tl
+    \group_end:
+  }
+
+% ----------------------------------------------------------------------------
+
+\NewDocumentCommand \blank {som}
+  {
+    \group_begin:
+      \IfNoValueF {#2} { \keys_set:nn {xsim/blank} {#2} }
+      \mode_if_vertical:TF
+        {
+          \IfBooleanTF {#1}
+            { \xsim_blank:n {#3} }
+            {
+              \bool_if:NT \l__xsim_blank_linespread_bool
+                { \linespread { \l__xsim_blank_linespread_tl } \selectfont }
+              \noindent \null \xsim_blank:n {#3} \par
+            }
+        }
+        { \xsim_blank:n {#3} }
+    \group_end:
+  }
+
+\NewDocumentCommand \examspace { sm }
+  {
+    \IfBooleanTF {#1}
+      { \xsim_examspace:nn { \c_true_bool } {#2} }
+      { \xsim_examspace:nn { \c_false_bool } {#2} }
+  }
+
+% ----------------------------------------------------------------------------
+  
+\NewDocumentCommand \gradingtable {O{}}
+  {
+    \group_begin:
+      \keys_set:nn {xsim/grading-table} { template = default , type = , #1}
+      \xsim_setup_template:nnV {table} \l_xism_grading_table_template_tl
+        {
+          \providecommand* \ExerciseTableCode {}
+          \providecommand* \ExerciseTableType [1] {}
+          \providecommand* \ExerciseType {}
+          \tl_set_eq:NN \ExerciseType \l_xism_grading_table_exercise_type_tl
+          \renewcommand* \ExerciseTableCode {}
+          \renewcommand* \ExerciseTableType [1]
+            { \XSIMifblankTF { \ExerciseType } {##1} { \ExerciseType } }
+        }
+      \xsim_use_template:nV {table} \l_xism_grading_table_template_tl
+    \group_end:
+  }
+
+% ----------------------------------------------------------------------------
+
+\NewDocumentCommand \printsolution {O{}mm}
+  { \xsim_insert:nnnn {#2} {#3} {#1} {solution} }
+
+\NewDocumentCommand \printexercise {O{}mm}
+  { \xsim_insert:nnnn {#2} {#3} {#1} {exercise} }
+  
+% ----------------------------------------------------------------------------
+  
+\NewDocumentCommand \printsolutionstype {sO{}m}
+  {
+    \IfBooleanTF {#1}
+      { \xsim_print_type_solutions:nnn { \c_true_bool } {#2} {#3} }
+      { \xsim_print_type_solutions:nnn { \c_false_bool } {#2} {#3} }
+  }
+
+\NewDocumentCommand \printsolutions {sO{}}
+  {
+    \IfBooleanTF {#1}
+      { \xsim_print_all_solutions_per_type:nn { \c_true_bool } {#2} }
+      { \xsim_print_all_solutions_per_type:nn { \c_false_bool } {#2} }
+  }
+
+\NewDocumentCommand \printallsolutions {sO{}}
+  {
+    \IfBooleanTF {#1}
+      { \xsim_print_all_solutions_per_id:nn { \c_true_bool } {#2} }
+      { \xsim_print_all_solutions_per_id:nn { \c_false_bool } {#2} }
+  }
+
+% ----------------------------------------------------------------------------
+
+\NewDocumentCommand \xsimsetup {m}
+  { \xsim_setup:n {#1} }
+
+% ----------------------------------------------------------------------------
+\NewExpandableDocumentCommand \XSIMifchapterTF {+m+m}
+  { \xsim_if_chapter:TF {#1} {#2} }
+
+\NewExpandableDocumentCommand \XSIMifchapterT {+m}
+  { \xsim_if_chapter:T {#1} }
+
+\NewExpandableDocumentCommand \XSIMifchapterF {+m}
+  { \xsim_if_chapter:F {#1} }
+
+% ----------------------------------------------------------------------------
+\tex_endinput:D
diff --git a/Master/texmf-dist/tex/latex/xsim/xsim.modules.code.tex b/Master/texmf-dist/tex/latex/xsim/xsim.modules.code.tex
new file mode 100644
index 00000000000..1e5d7d5cfa1
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/xsim/xsim.modules.code.tex
@@ -0,0 +1,211 @@
+% ----------------------------------------------------------------------------
+% the XSIM package - modules module
+% 
+%   eXercise Sheets IMproved
+% 
+% ----------------------------------------------------------------------------
+% Clemens Niederberger
+% Web:    https://github.com/cgnieder/xsim
+% E-Mail: contact@mychemistry.eu
+% ----------------------------------------------------------------------------
+% Copyright 2017 Clemens Niederberger
+% 
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+% 
+% This work has the LPPL maintenance status `maintained'.
+% 
+% The Current Maintainer of this work is Clemens Niederberger.
+% ----------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% ----------------------------------------------------------------------------
+%
+% this is a pseudo module as it does the actual definitions for the whole
+% module loading stuff; we do this so both packages `xsimverb' and `xsim' can
+% use the `verbwrite' module
+\RequirePackage{scrlfile}
+\ExplSyntaxOn
+
+\msg_new:nnn {xsim} {module-missing}
+  {
+    You've~ requested~ the~ xsim~ module~ `#1'~ but~ it~ appears~ to~
+    be~ missing~ on~ your~ system.~ Maybe~ you've~ misspelled~ the~ name?~
+    Loading~ the~ module~ will~ abort~ \msg_line_context:
+  }
+
+\msg_new:nnn {xsim} {loading-module}
+  { Loading~ module~ `#1'~ ... }
+
+\msg_new:nnn {xsim} {wrong-module-name}
+  { The~ module~ file~ name~ is~ `#2'~ but~ it~ provides~ module~ `#1'. }
+
+\msg_new:nnn {xsim} {forbidden-module}
+  {
+    You've~ requested~ the~ xsim~ module~ `modules'~ \msg_line_context: .~
+  This~ module~ is~ a~ pseudo~ module~ which~ may~ not~ be~ loaded~ through~
+  the~ module~ loading~ mechansim.
+  }
+
+% ----------------------------------------------------------------------------
+
+\tl_const:Nn \c__xsim_module_extension_tl {code.tex}
+\tl_const:Nn \c__xsim_module_prefix_tl    {xsim}
+
+\seq_new:N \g__xsim_loaded_modules_seq
+\prop_new:N \g__xsim_loaded_modules_prop
+
+\cs_new_protected:Npn \xsim_load_modules:n #1
+  { \clist_map_inline:nn {#1} { \xsim_load_module:n {##1} } }
+
+\cs_new_protected:Npn \xsim_load_module:n #1
+  {
+    \tl_set:Nx \l_tmpa_tl { \tl_trim_spaces:n {#1} }
+    \str_if_eq_x:nnTF { \l_tmpa_tl } {modules}
+      { \msg_error:nn {xsim} {forbidden-module} }
+      {  \__xsim_load_module:V \l_tmpa_tl }
+  }
+
+\cs_new_protected:Npn \__xsim_load_module:n #1
+  {
+    \xsim_if_module_loaded:nF {#1}
+      {
+        \xsim_if_module_exist:nTF {#1}
+          {
+            \__xsim_use_module_hook:nn {#1} {before}
+            \msg_info:nnn {xsim} {loading-module} {#1}
+            \@onefilewithoptions
+              {\c__xsim_module_prefix_tl.#1}[][]
+              \c__xsim_module_extension_tl
+            \__xsim_use_module_hook:nn {#1} {after}
+          }
+          { \msg_error:nnn {xsim} {module-missing} {#1} }
+      }
+  }
+\cs_generate_variant:Nn \__xsim_load_module:n { V }
+
+\prg_new_conditional:Npnn \xsim_if_module_loaded:n #1 {p,T,F,TF}
+  {
+    \seq_if_in:NnTF \g__xsim_loaded_modules_seq {#1}
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+\prg_new_conditional:Npnn \xsim_if_module_exist:n #1 {p,T,F,TF}
+  {
+    \file_if_exist:nTF
+      {\c__xsim_module_prefix_tl.#1.\c__xsim_module_extension_tl}
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+% --------------------------------------------------------------------------
+% module hooks:
+% #1: module
+% #2: code
+\cs_new_protected:Npn \xsim_after_module:nn #1#2
+  {
+    \xsim_if_module_loaded:nTF {#1}
+      {#2}
+      { \__xsim_add_to_module_hook:nnn {#1} {after} {#2} }
+  }
+
+% #1: module
+% #2: code
+\cs_new_protected:Npn \xsim_before_module:nn #1#2
+  {
+    \xsim_if_module_loaded:nF {#1}
+      { \__xsim_add_to_module_hook:nnn {#1} {before} {#2} }
+  }
+
+% #1: module
+% #2: hook name
+% #3: code
+\cs_new_protected:Npn \__xsim_add_to_module_hook:nnn #1#2#3
+  {
+    \xsim_if_module_loaded:nF {#1}
+      {
+        \tl_if_exist:cF {g__xsim_module_#1_#2_hook_tl}
+          { \tl_new:c {g__xsim_module_#1_#2_hook_tl} }
+        \tl_gput_right:cn {g__xsim_module_#1_#2_hook_tl} {#3}
+      }
+  }
+
+% #1: module
+% #2: hook name
+\cs_new_protected:Npn \__xsim_use_module_hook:nn #1#2
+  {
+    \tl_if_exist:cT {g__xsim_module_#1_#2_hook_tl}
+      {
+        \tl_use:c {g__xsim_module_#1_#2_hook_tl}
+        \tl_gclear:c {g__xsim_module_#1_#2_hook_tl}
+      }
+  }
+
+% --------------------------------------------------------------------------
+
+\tl_new:N \l__xsim_module_date_tl
+\tl_new:N \l__xsim_module_version_tl
+
+\tl_if_exist:NF \c_xsim_date_tl
+  { \tl_set:Nx \l__xsim_module_date_tl {\c_xsimverb_date_tl} }
+\tl_if_exist:NF \c_xsim_version_tl
+  { \tl_set:Nx \l__xsim_module_version_tl {\c_xsimverb_version_tl} }
+
+\AfterPackage*{xsim}
+  {
+    \tl_set:Nx \l__xsim_module_date_tl {\c_xsim_date_tl}
+    \tl_set:Nx \l__xsim_module_version_tl {\c_xsim_version_tl}
+  }
+  
+\cs_new_protected:Npn \__xsim_module:nn #1#2
+  {
+    \seq_gput_right:Nn \g__xsim_loaded_modules_seq {#1}
+    \prop_gput:Nnn \g__xsim_loaded_modules_prop {#1} {#2}
+    \str_if_eq_x:nnF
+      {\c__xsim_module_prefix_tl.#1.\c__xsim_module_extension_tl}
+      {\@currname.\@currext}
+      {
+        \msg_error:nnnxx {xsim} {wrong-module-name}
+          {#1}
+          {\@currname.\@currext}
+      }
+    \ProvidesFile
+      {\c__xsim_module_prefix_tl.#1.\c__xsim_module_extension_tl}
+      [
+        \l__xsim_module_date_tl
+        \c_space_tl
+        v \l__xsim_module_version_tl
+        \c_space_tl
+        xsim~ module~ `#1'~ (#2)
+      ]
+  }
+\cs_generate_variant:Nn \msg_error:nnnn {nnnx}
+
+% --------------------------------------------------------------------------
+% define a xsim module:
+% #1: name
+% #2: description
+\NewDocumentCommand \XSIMmodule {mm} { \__xsim_module:nn {#1} {#2}
+\ExplSyntaxOn }
+
+% --------------------------------------------------------------------------
+% style files
+\NewDocumentCommand \xsimstyle   {sm}
+  {
+    \__xsim_module:nn {#2} {}
+    \IfBooleanF {#1} { \ExplSyntaxOn }
+  }
+
+\cs_new_protected:Npn \xsim_style_options:nn #1#2
+  { \keys_define:nn {xsim/#1} {#2} }
+
+\NewDocumentCommand \loadxsimstyle {m} { \xsim_load_module:n {#1} }
+
+% --------------------------------------------------------------------------
+\tex_endinput:D
diff --git a/Master/texmf-dist/tex/latex/xsim/xsim.properties.code.tex b/Master/texmf-dist/tex/latex/xsim/xsim.properties.code.tex
new file mode 100644
index 00000000000..ec88d1be00a
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/xsim/xsim.properties.code.tex
@@ -0,0 +1,495 @@
+% ----------------------------------------------------------------------------
+% the XSIM package - properties module
+% 
+%   eXercise Sheets IMproved
+% 
+% ----------------------------------------------------------------------------
+% Clemens Niederberger
+% Web:    https://github.com/cgnieder/xsim
+% E-Mail: contact@mychemistry.eu
+% ----------------------------------------------------------------------------
+% Copyright 2017 Clemens Niederberger
+% 
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+% 
+% This work has the LPPL maintenance status `maintained'.
+% 
+% The Current Maintainer of this work is Clemens Niederberger.
+% ----------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% ----------------------------------------------------------------------------
+\XSIMmodule{properties}{properties of exercises}
+
+\xsim_load_modules:n {base,auxfile}
+
+\msg_new:nnn {xsim} {unknown-property}
+  {
+    You~ tried~ to~ set~ the~ property~ `#1'~ \msg_line_context: . \\
+    This~ property~ does~ not~ exist.~ Check~ for~ a~ typo~ or~ \\
+    define~ the~ property~ yourself.
+  }
+
+\msg_new:nnn {xsim} {property-unique}
+  {
+    You~ tried~ to~ set~ the~ property~ `#1'~ \msg_line_context: . \\
+    This~ property~ has~ to~ have~ a~ unique~ value~ and~ thus~ \\
+    cannot~ be~ set~ to~ `#2'~ since~ this~ value~ is~ already~ talen.
+  }
+
+\msg_new:nnn {xsim} {no-boolean-property}
+  {
+    You~ tried~ to~ check~ the~ boolean~ value~ of~ property~ `#1'~
+    \msg_line_context: . \\
+    However,~ property~ `#1'~ is~ not~ a~ boolean~ property!
+  }
+  
+\seq_new:N \l__xsim_properties_seq
+\seq_new:N \l__xsim_boolean_properties_seq
+\seq_new:N \l__xsim_unique_properties_seq
+\seq_new:N \l__xsim_noupdate_properties_seq
+\prop_new:N \g__xsim_properties_prop
+
+% new property:
+% #1: boolean if unique
+% #2: boolean if boolean
+% #3: boolean if noupdate
+% #4: property name
+\cs_new_protected:Npn \xsim_declare_property:nnnn #1#2#3#4
+  {
+    \xsim_if_property_exist:nF {#4}
+      {
+        \seq_put_right:Nn \l__xsim_properties_seq {#4}
+        \bool_if:nTF {#3}
+          {
+            \seq_if_in:NnF \l__xsim_noupdate_properties_seq {#4}
+              { \seq_put_right:Nn \l__xsim_noupdate_properties_seq {#4} }
+          }
+          { \xsim_new_list:n {#4} }
+        \bool_if:nTF {#2}
+          {
+            \xsim_verbose:n
+              { Declaring~ new~ boolean~ exercise~ property~ `#4'. }
+            \seq_if_in:NnF \l__xsim_boolean_properties_seq {#4}
+              { \seq_put_right:Nn \l__xsim_boolean_properties_seq {#4} }
+          }
+          {
+            \bool_if:nTF {#1}
+              {
+                \xsim_verbose:n
+                  { Declaring~ new~ unique~ exercise~ property~ `#4'. }
+                \seq_if_in:NnF \l__xsim_unique_properties_seq {#4}
+                  { \seq_put_right:Nn \l__xsim_unique_properties_seq {#4} }
+                \seq_new:c {l__xsim_unique_property_#4_values_seq}
+                \prop_new:c {g__xsim_property_#4_type_prop}
+                \prop_new:c {g__xsim_property_#4_id_prop}
+              }
+              { \xsim_verbose:n { Declaring~ new~ exercise~ property~ `#4'. } }
+          }
+        \bool_if:nF {#3}
+          {
+            \AtEndDocument { \xsim_update_list:n {#4} }
+            \AtBeginDocument { \__xsim_set_property_from_list:n {#4} }
+          }
+      }
+  }
+
+% check if property exists:
+\prg_new_conditional:Npnn \xsim_if_property_exist:n #1 {p,T,F,TF}
+  {
+    \seq_if_in:NnTF \l__xsim_properties_seq {#1}
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+\cs_generate_variant:Nn \xsim_if_property_exist:nTF {x}
+
+\prg_new_conditional:Npnn \xsim_if_property_noupdate:n #1 {p,T,F,TF}
+  {
+    \seq_if_in:NnTF \l__xsim_noupdate_properties_seq {#1}
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+\cs_generate_variant:Nn \xsim_if_property_noupdate:nF {V}
+
+\prg_new_conditional:Npnn \xsim_if_property_boolean:n #1 {p,T,F,TF}
+  {
+    \seq_if_in:NnTF \l__xsim_boolean_properties_seq {#1}
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+\prg_new_conditional:Npnn \xsim_if_property_unique:n #1 {p,T,F,TF}
+  {
+    \seq_if_in:NnTF \l__xsim_unique_properties_seq {#1}
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+% #1: property
+% #2: value
+\prg_new_conditional:Npnn \xsim_if_property_unique_value:nn #1#2 {p,T,F,TF}
+  {
+    \xsim_if_property_unique:nTF {#1}
+      {
+        \seq_if_in:cnTF {l__xsim_unique_property_#1_values_seq} {#2}
+          { \prg_return_true: }
+          { \prg_return_false: }
+      }
+      { \prg_return_false: }
+  }
+
+% #1: type
+% #2: id
+% #3: property
+% #4: value
+\cs_new_protected:Npn \xsim_set_property:nnnn #1#2#3#4
+  {
+    \xsim_if_property_exist:nTF {#3}
+      {
+        \xsim_if_property_set:nnnTF {#1} {#2} {#3}
+          {
+            \xsim_if_property_unique_value:nnTF {#3} {#4}
+              { \msg_warning:nnnn {xsim} {property-unique} {#3} {#4} }
+              {
+                \xsim_if_property_boolean:nTF {#3}
+                  { \__xsim_set_boolean_property:nnnn {#1} {#2} {#3} {#4} }
+                  {
+                    \xsim_if_property_unique:nTF {#3}
+                      { \__xsim_set_unique_property:nnnn {#1} {#2} {#3} {#4} }
+                      { \__xsim_set_property:nnnn {#1} {#2} {#3} {#4} }
+                  }
+              }
+          }
+          {
+            \xsim_if_property_boolean:nTF {#3}
+              { \__xsim_set_boolean_property:nnnn {#1} {#2} {#3} {#4} }
+              {
+                \xsim_if_property_unique:nTF {#3}
+                  { \__xsim_set_unique_property:nnnn {#1} {#2} {#3} {#4} }
+                  { \__xsim_set_property:nnnn {#1} {#2} {#3} {#4} }
+              }
+          }
+      }
+      { \msg_error:nnn {xsim} {unknown-property} {#3} }  
+  }
+\cs_generate_variant:Nn \xsim_set_property:nnnn {nnxx,nnnV,nV,nVnx,nnnx}
+
+\cs_new_protected:Npn \__xsim_set_boolean_property:nnnn #1#2#3#4
+  {
+    \str_case_x:nnTF { \str_lower_case:n {#4} }
+      {
+        {} {}
+        {true} {}
+      }
+      { \__xsim_set_property:nnnn {#1} {#2} {#3} {true} }
+      { \__xsim_set_property:nnnn {#1} {#2} {#3} {false} }
+  }
+
+\cs_new_protected:Npn \__xsim_set_unique_property:nnnn #1#2#3#4
+  {
+    \__xsim_set_property:nnnn {#1} {#2} {#3} {#4}
+    \__xsim_set_property_reverse:nnnn {#1} {#2} {#3} {#4}
+  }
+
+% #1: type
+% #2: id
+% #3: property
+\cs_new_protected:Npn \xsim_unset_property:nnn #1#2#3
+  {
+    \xsim_if_property_exist:nTF {#3}
+      { \__xsim_unset_property:nnn {#1} {#2} {#3} }
+      { \msg_error:nnn {xsim} {unknown-property} {#3} }  
+  }
+\cs_generate_variant:Nn \xsim_unset_property:nnn {nx,nnx,nV}
+
+% #1: type
+% #2: id
+% #3: property
+% #4: value
+\cs_new_protected:Npn \__xsim_set_property:nnnn #1#2#3#4
+  {
+    \xsim_verbose:n
+      {
+        Setting~ property~ `#3'~ of~ exercise~ type~ `#1'~ id~ `#2'~ to~
+        value~ `#4'.
+      }
+   \__xsim_remove_property_from_list:nnn {#1} {#2} {#3}
+    % now we can safely add the property to the list:
+    \xsim_add_to_list:nn {#3} {#1-#2=={#4}}
+    \prop_gput:Nnn \g__xsim_properties_prop {#2!#1!#3} {#4}
+  }
+\cs_generate_variant:Nn \__xsim_set_property:nnnn {VVnV}
+
+% #1: type
+% #2: id
+% #3: property
+% #4: value
+\cs_new_protected:Npn \__xsim_set_property_reverse:nnnn #1#2#3#4
+  {
+    \prop_gput:cnn {g__xsim_property_#3_type_prop} {#4} {#1}
+    \prop_gput:cnn {g__xsim_property_#3_id_prop} {#4} {#2}
+  }
+
+% #1: type
+% #2: id
+% #3: property
+\cs_new_protected:Npn \__xsim_unset_property:nnn #1#2#3
+  {
+    \xsim_verbose:n
+      { Un-setting~ property~ `#3'~ of~ exercise~ type~ `#1'~ id~ `#2'. }
+    \__xsim_remove_property_from_list:nnn {#1} {#2} {#3}
+    \prop_gremove:Nn \g__xsim_properties_prop {#2!#1!#3}
+  }
+
+\tl_set:Nx \l__xsim_tmpa_tl { \cs_to_str:N \{ }
+\tl_set:Nx \l__xsim_tmpb_tl { \cs_to_str:N \} }
+\use:x
+  {
+    \cs_new_protected:Npn
+    \exp_not:N \__xsim_extract_property_list_entry:NNNwww
+    ##1##2##3##4-##5== \l__xsim_tmpa_tl ##6 \l__xsim_tmpb_tl
+    \exp_not:N \q_stop
+  }
+  {
+    \str_set:Nn #1 {#4}
+    \str_set:Nn #2 {#5}
+    \str_set:Nn #3 {#6}
+  }
+
+\cs_new_protected:Npn \__xsim_remove_property_from_list:nnn #1#2#3
+  {
+    % make sure we change the entry if it has been recorded previously:
+    \xsim_foreach_list_entry:nn {#3}
+      {
+        \__xsim_extract_property_list_entry:NNNwww
+          \l__xsim_tmpa_str \l__xsim_tmpb_str \l__xsim_tmpc_str ##1 \q_stop
+        \str_if_eq:xnT { \l__xsim_tmpa_str - \l__xsim_tmpb_str } {#1-#2}
+          {
+            \xsim_remove_from_list:nx {#3}
+              { #1-#2 == {\l__xsim_tmpc_str} }
+          }
+      }
+    % make sure we change the entry if it has been set during the current run:
+    \xsim_foreach_new_list_entry:nn {#3}
+      {
+        \__xsim_extract_property_list_entry:NNNwww
+          \l__xsim_tmpa_str \l__xsim_tmpb_str \l__xsim_tmpc_str ##1 \q_stop
+        \str_if_eq:xnT { \l__xsim_tmpa_str - \l__xsim_tmpb_str } {#1-#2}
+          {
+            \xsim_remove_from_list:nx {#3}
+              { #1-#2 == {\l__xsim_tmpc_str} }
+          }
+      }
+  }
+
+\cs_new_protected:Npn \__xsim_set_property_from_list:n #1
+  {
+    \xsim_foreach_list_entry:nn {#1}
+      {
+        \__xsim_extract_property_list_entry:NNNwww
+          \l__xsim_tmpa_str \l__xsim_tmpb_str \l__xsim_tmpc_str ##1 \q_stop
+        \tl_set_rescan:Nnx \l__xsim_tmpc_tl {} { \l__xsim_tmpc_str }
+        \__xsim_set_property:VVnV
+          \l__xsim_tmpa_str
+          \l__xsim_tmpb_str
+          {#1}
+          \l__xsim_tmpc_tl
+      }
+  }
+
+% set properties:
+% #1: type
+% #2: id
+% #3: csv list of properties
+\cs_new_protected:Npn \xsim_set_properties:nnn #1#2#3
+  {
+    \clist_map_inline:nn {#3}
+      {
+        \seq_set_split:Nnx \l__xsim_tmpa_seq {=} { \tl_trim_spaces:n {##1} }
+        \xsim_set_property:nnxx
+          {#1}
+          {#2}
+          { \seq_item:Nn \l__xsim_tmpa_seq {1} }
+          { \seq_item:Nn \l__xsim_tmpa_seq {2} }
+      }
+    \xsim_property_set_aliases:nn {#1} {#2}
+  }
+\cs_generate_variant:Nn \xsim_set_properties:nnn {nnx,nxx,nV,nVx}
+
+% check if property is set:
+% #1: type
+% #2: id
+% #3: property
+\prg_new_protected_conditional:Npnn \xsim_if_property_set:nnn #1#2#3 {T,F,TF}
+  {
+    \prop_if_in:NxTF \g__xsim_properties_prop
+      { #2 ! #1 ! #3 }
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+\cs_generate_variant:Nn \xsim_if_property_set:nnnTF {nnx,xx,nV}
+\cs_generate_variant:Nn \xsim_if_property_set:nnnF  {nx,nnx,xx}
+\cs_generate_variant:Nn \xsim_if_property_set:nnnT  {nnx,xx}
+
+% ----------------------------------------------------------------------------
+
+\prop_new:N \g__xsim_property_aliases_prop
+\seq_new:N \g__xsim_property_aliases_seq
+
+% #1: property
+\prg_new_conditional:Npnn \xsim_if_property_alias:n #1 {p,T,F,TF}
+  {
+    \prop_if_in:NnTF \g__xsim_property_aliases_prop {#1}
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+% #1: property
+\cs_new:Npn \xsim_property_alias:n #1
+  { \prop_item:Nn \g__xsim_property_aliases_prop {#1} }
+
+% #1: property
+% #2: alias of
+\cs_new_protected:Npn \xsim_make_property_alias:nn #1#2
+  {
+    \xsim_if_property_alias:nF {#1}
+      {
+        \xsim_verbose:n
+          { Making~ property~ `#1'~ an~ alias~ of~ property~ `#2'. }
+        \prop_new:c {g__xsim_property_#1_alias_prop}
+        \prop_gput:Nnn \g__xsim_property_aliases_prop {#1} {#2}
+        \seq_gput_right:Nn \g__xsim_property_aliases_seq {#1}
+      }
+  }
+
+% #1: type
+% #2: id
+% #3: property
+\cs_new_protected:Npn \xsim_property_set_alias:nnn #1#2#3
+  {
+    \xsim_if_property_set:nnnF {#1} {#2} {#3}
+      {
+        \xsim_if_property_set:nnxT {#1} {#2}
+          { \xsim_property_alias:n {#3} }
+          { 
+            \xsim_set_property:nnnx {#1} {#2} {#3}
+              {
+                \xsim_get_property:nnf {#1} {#2}
+                  { \xsim_property_alias:n {#3} }
+              }
+          }
+      }
+    \xsim_if_property_set:nnxT {#1} {#2}
+      { \xsim_property_alias:n {#3} }
+      {
+        \prop_gput:cxx {g__xsim_property_#3_alias_prop}
+          { \xsim_get_property:nnn {#1} {#2} {#3} }
+          {
+            \xsim_get_property:nnf {#1} {#2}
+              { \xsim_property_alias:n {#3} }
+          }
+      }
+  }
+\cs_generate_variant:Nn \xsim_property_set_alias:nnn {nV}
+
+% #1: type
+% #2: id
+\cs_new_protected:Npn \xsim_property_set_aliases:nn #1#2
+  {
+    \seq_map_inline:Nn \g__xsim_property_aliases_seq
+      { \xsim_property_set_alias:nnn {#1} {#2} {##1} }
+  }
+
+% ----------------------------------------------------------------------------
+
+% retrieve properties:
+% #1: type
+% #2: id
+% #3: property
+\cs_new:Npn \xsim_get_property:nnn #1#2#3
+  { \prop_item:Nn \g__xsim_properties_prop { #2 ! #1 ! #3 } }
+\cs_generate_variant:Nn \xsim_get_property:nnn {nx,xx,oo,no,nnf,nf,oof,nV}
+
+\cs_new:Npn \__xsim_get_property_tmp:n #1 {}
+\cs_generate_variant:Nn \__xsim_get_property_tmp:n {V}
+
+% #1: property
+% #2: value
+\cs_new:Npn \xsim_get_id_for_property:nn #1#2
+  { \prop_item:cn {g__xsim_property_#1_id_prop} {#2} }
+
+% #1: property
+% #2: value
+\cs_new:Npn \xsim_get_type_for_property:nn #1#2
+  { \prop_item:cn {g__xsim_property_#1_type_prop} {#2} }
+\cs_generate_variant:Nn \xsim_get_type_for_property:nn {nV}
+
+% #1: type
+% #2: id
+% #3: property
+\cs_new_protected:Npn \xsim_get_property_if_set:nnnTF #1#2#3#4#5
+  {
+    \group_begin:
+      \xsim_if_property_exist:nTF {#3}
+        {
+          \xsim_if_property_set:nnnTF {#1} {#2} {#3}
+            {    
+              \tl_set:Nx \PropertyValue
+                { \xsim_get_property:nnn {#1} {#2} {#3} }
+              \cs_set:Npn \__xsim_get_property_tmp:n ##1 {#4}
+              \__xsim_get_property_tmp:V \PropertyValue
+            }
+            {#5}
+        }
+        { \msg_error:nnn {xsim} {unknown-property} {#3} }
+    \group_end:
+  }
+\cs_new_protected:Npn \xsim_get_property_if_set:nnnT #1#2#3#4
+  { \xsim_get_property_if_set:nnnTF {#1} {#2} {#3} {#4} {} }
+\cs_new_protected:Npn \xsim_get_property_if_set:nnnF #1#2#3#4
+  { \xsim_get_property_if_set:nnnTF {#1} {#2} {#3} {} {#4} }
+\cs_generate_variant:Nn \xsim_get_property_if_set:nnnTF {oo}
+
+% #1: type
+% #2: id
+% #3: property
+\prg_new_conditional:Npnn \xsim_if_boolean_property:nnn #1#2#3 {T,F,TF}
+  {
+    \xsim_if_property_exist:nTF {#3}
+      {
+        \xsim_if_property_boolean:nTF {#3}
+          {
+            \xsim_if_property_set:nnnTF {#1} {#2} {#3}
+              {
+                \bool_if:cTF { c_ \xsim_get_property:nnn {#1} {#2} {#3} _bool}
+                  { \prg_return_true: }
+                  { \prg_return_false: }
+              }
+              { \prg_return_false: }
+          }
+          { \msg_error:nnn {xsim} {no-boolean-property} {#3} }
+      }
+      { \msg_error:nnn {xsim} {unknown-property} {#3} }
+  }
+\cs_generate_variant:Nn \xsim_if_boolean_property:nnnTF {oo}
+\cs_generate_variant:Nn \xsim_if_boolean_property:nnnF  {nV}
+
+\cs_new_protected:Npn \xsim_save_property:nnnN #1#2#3#4
+  { \prop_get:NnN \g__xsim_properties_prop { #2 ! #1 ! #3 } #4 }
+\cs_generate_variant:Nn \xsim_save_property:nnnN {nx,xx}
+
+\cs_new_protected:Npn \xsim_gsave_property:nnnN #1#2#3#4
+  {
+    \xsim_save_property:nnnN {#1} {#2} {#3} #4
+    \tl_gset:NV #4 #4
+  }
+\cs_generate_variant:Nn \xsim_gsave_property:nnnN {nx,xx}
+
+% ----------------------------------------------------------------------------
+\tex_endinput:D
diff --git a/Master/texmf-dist/tex/latex/xsim/xsim.random.code.tex b/Master/texmf-dist/tex/latex/xsim/xsim.random.code.tex
new file mode 100644
index 00000000000..3120c800bd8
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/xsim/xsim.random.code.tex
@@ -0,0 +1,307 @@
+% ----------------------------------------------------------------------------
+% the XSIM package - random module
+% 
+%   eXercise Sheets IMproved
+% 
+% ----------------------------------------------------------------------------
+% Clemens Niederberger
+% Web:    https://github.com/cgnieder/xsim
+% E-Mail: contact@mychemistry.eu
+% ----------------------------------------------------------------------------
+% Copyright 2017 Clemens Niederberger
+% 
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+% 
+% This work has the LPPL maintenance status `maintained'.
+% 
+% The Current Maintainer of this work is Clemens Niederberger.
+% ----------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% ----------------------------------------------------------------------------
+\XSIMmodule{random}{randomly select exercises from collections}
+
+\xsim_load_modules:n {collections}
+
+\tl_new:N    \l_xsim_random_collection_tl
+\tl_new:N    \l_xsim_random_exclude_list_tl
+\tl_new:N    \l__xsim_print_random_choice_tl
+\tl_const:Nn \c__xsim_print_random_both_tl {both}
+\tl_const:Nn \c__xsim_print_random_exercise_tl {exercise}
+\tl_const:Nn \c__xsim_print_random_solution_tl {solution}
+\seq_new:N   \g__xsim_random_list_seq
+\seq_new:N   \l__xsim_allowed_exercise_ids_seq
+\int_new:N   \g__xsim_random_list_id_int
+\bool_new:N  \l__xsim_sort_random_bool
+
+% #1: random list id
+% #2: csv list of integers
+\xsim_new_aux_cs:cpn {random} #1#2
+  {
+    \xsim_random_list_if_exist:nF {#1}
+      { \xsim_new_random_list:n {#1} }
+    \xsim_set_random_list:nn {#1} {#2}
+  }
+
+\cs_new_protected:Npn \xsim_new_random_list:n #1
+  {
+    \xsim_verbose:n {Defining~ new~ random~ list~ `#1'}
+    \seq_new:c {g__xsim_random_#1 _seq}
+  }
+
+\cs_new_protected:Npn \xsim_set_random_list:nn #1#2
+  { \seq_gset_from_clist:cn {g__xsim_random_#1_seq} {#2} }
+
+\cs_new_protected:Npn \xsim_set_random_list_from_seq:nN #1#2
+  { \seq_gset_eq:cN {g__xsim_random_#1_seq} #2 }
+
+\cs_new:Npn \xsim_use_random_list:nn #1#2
+  { \seq_use:cn {g__xsim_random_#1_seq} {#2} }
+
+\cs_new_protected:Npn \xsim_map_random_list:nn #1#2
+  { \seq_map_inline:cn {g__xsim_random_#1_seq} {#2} }
+
+\prg_new_conditional:Npnn \xsim_random_list_if_exist:n #1 {p,T,F,TF}
+  {
+    \seq_if_exist:cTF {g__xsim_random_#1_seq}
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+\prg_new_conditional:Npnn \xsim_random_list_if_empty:n #1 {p,T,F,TF}
+  {
+    \seq_if_empty:cTF {g__xsim_random_#1_seq}
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+% #1: random list id
+% #2: sequence variable to set list from
+\cs_new_protected:Npn \xsim_save_random_list:nN #1#2
+  {
+    \xsim_random_list_if_exist:nF {#1}
+      { \xsim_new_random_list:n {#1} }
+    \xsim_random_list_if_empty:nT {#1}
+      { \xsim_set_random_list_from_seq:nN {#1} #2 }
+    \xsim_verbose:n {Saving~ random~ list~ `#1'}
+    \xsim_add_cs_to_aux:nn {random}
+      { {#1} { \xsim_use_random_list:nn {#1} {,} } }
+  }
+
+% #1: collection
+% #2: number of items
+% #3: csv list of excluded ids
+\cs_new_protected:Npn \xsim_print_random_list:nnn #1#2#3
+  {
+    \xsim_if_collection_exists:nTF {#1}
+      {
+        \int_gincr:N \g__xsim_random_list_id_int
+        \int_compare:nNnTF { \xsim_collection_count:n {#1} } = {0}
+          { \xsim_rerun: }
+          {
+            % generate seq of allowed ids from collection:
+            \xsim_foreach_exercise_id:n
+              {
+                \tl_set:Nx \l__xsim_tmpa_tl
+                  { \xsim_get_type_for_property:nn {id} {##1} }
+                \xsim_if_in_collection:nVnT {#1} \l__xsim_tmpa_tl {##1}
+                  {
+                    \clist_if_in:nnF {#3} {##1}
+                      { \seq_put_right:Nn \l__xsim_allowed_exercise_ids_seq {##1} }
+                  }
+              }
+            \int_compare:nNnTF
+              {#2}
+               >
+              { \seq_count:N \l__xsim_allowed_exercise_ids_seq }
+              {
+                \int_set:Nn \l__xsim_tmpa_int
+                  { \seq_count:N \l__xsim_allowed_exercise_ids_seq }
+              }
+              { \int_set:Nn \l__xsim_tmpa_int {#2} }
+            % generate random list:
+            \xsim_generate_random_list:nnnN
+              { \int_to_alph:n { \g__xsim_random_list_id_int } }
+              { \seq_count:N \l__xsim_allowed_exercise_ids_seq }
+              { \l__xsim_tmpa_int }
+              \g__xsim_random_list_seq
+          }
+        \xsim_save_random_list:nN
+          { \int_to_alph:n { \g__xsim_random_list_id_int } }
+          \g__xsim_random_list_seq
+        \xsim_verbose:x
+          {
+            Printing~ exercises~ of~ random~ list~
+            `\int_to_alph:n { \g__xsim_random_list_id_int }'~ of~
+            collection~ `#1'
+          }
+        \xsim_print_random_exercises:Nn
+          \l__xsim_allowed_exercise_ids_seq
+          { \int_to_alph:n { \g__xsim_random_list_id_int } }
+      }
+      { \msg_error:nnn {xsim} {unknown-collection} {#1} }
+  }
+\cs_generate_variant:Nn \xsim_print_random_list:nnn {VnV}
+
+% #1: random list id
+% #2: max number to choose from
+% #3: number of items
+% #4: seq variable
+\cs_new_protected:Npn \xsim_generate_random_list:nnnN #1#2#3#4
+  {
+    \bool_if:nT
+      {
+        !\xsim_random_list_if_exist_p:n {#1}
+        ||
+        \xsim_random_list_if_empty_p:n {#1}
+      }
+      {
+        \xsim_verbose:n
+          {Generating~ random~ list~ `#1'~ with~ #3~ out~ of~ #2~ items}
+        \seq_gclear:N #4
+        \int_do_until:nNnn { \seq_count:N #4 } = {#3}
+          {
+            \tl_set:Nx \l__xsim_tmpa_tl
+              { \fp_eval:n { randint(#2) } }
+            \seq_if_in:NVF #4
+              \l__xsim_tmpa_tl
+              { \seq_gput_right:NV #4 \l__xsim_tmpa_tl }
+          }
+        \bool_if:NT \l__xsim_sort_random_bool
+          {
+            \seq_sort:Nn #4
+              {
+                \int_compare:nNnTF {##1} > {##2}
+                  { \sort_return_swapped: }
+                  { \sort_return_same: }
+              }
+          }
+      }
+  }
+
+% #1: seq variable of ids
+% #2: random list id
+\cs_new_protected:Npn \xsim_print_random_exercises:Nn #1#2
+  {
+    \bool_if:nT
+      {
+        \xsim_random_list_if_exist_p:n {#2}
+        &&
+        !\xsim_random_list_if_empty_p:n {#2}
+      }
+      {
+        \xsim_verbose:x
+          {
+            Printing~
+            \l__xsim_print_random_choice_tl \c_space_tl
+            \str_if_eq:onT { \l__xsim_print_random_choice_tl } {both}
+              { exercises~ and~ solutions~ }
+            of~ random~ list~ `#2'
+          }
+        \xsim_map_random_list:nn {#2}
+          {
+            \tl_set:Nx \l__xsim_tmpa_tl
+              { \seq_item:Nn #1 {##1} }
+            \tl_set:Nx \l__xsim_tmpb_tl
+              { \xsim_get_type_for_property:nV {id} \l__xsim_tmpa_tl }
+            \bool_if:nT
+              {
+                \tl_if_eq_p:NN
+                  \l__xsim_print_random_choice_tl
+                  \c__xsim_print_random_both_tl
+                ||
+                \tl_if_eq_p:NN
+                  \l__xsim_print_random_choice_tl
+                  \c__xsim_print_random_exercise_tl
+              }
+              {
+                \xsim_if_exercise_exists:VVT
+                  \l__xsim_tmpb_tl
+                  \l__xsim_tmpa_tl
+                  {
+                    \xsim_insert:VVnn
+                      \l__xsim_tmpb_tl
+                      \l__xsim_tmpa_tl
+                      {}
+                      {exercise}
+                  }
+              }
+            \bool_if:nT
+              {
+                \tl_if_eq_p:NN
+                  \l__xsim_print_random_choice_tl
+                  \c__xsim_print_random_both_tl
+                ||
+                \tl_if_eq_p:NN
+                  \l__xsim_print_random_choice_tl
+                  \c__xsim_print_random_solution_tl
+              }
+              {
+                \xsim_if_solution_exists:VVT
+                  \l__xsim_tmpb_tl
+                  \l__xsim_tmpa_tl
+                  {
+                    \xsim_insert:VVnn
+                      \l__xsim_tmpb_tl
+                      \l__xsim_tmpa_tl
+                      {}
+                      {solution}
+                  }
+              }
+          }
+      }
+  }
+
+\keys_define:nn {xsim/random}
+  {
+    sort       .bool_set:N = \l__xsim_sort_random_bool ,
+    sort       .initial:n  = true ,
+    collection .tl_set:N   = \l_xsim_random_collection_tl ,
+    collection .initial:n  = all~exercises ,
+    exclude    .code:n     = \__xsim_exclude_ids:n {#1} ,
+    print             .choice: ,
+    print/exercises   .code:n =
+      \tl_set:Nn \l__xsim_print_random_choice_tl {exercise} ,
+    print/solutions   .code:n =
+      \tl_set:Nn \l__xsim_print_random_choice_tl {solution} ,
+    print/both        .code:n =
+      \tl_set:Nn \l__xsim_print_random_choice_tl {both} ,
+    print/unknown     .code:n =
+      \msg_warning:nnn {xsim} {print-collection-choice} {#1}
+      \tl_set:Nn \l__xsim_print_random_choice_tl {exercise} ,
+    print             .initial:n = exercises
+  }
+
+\cs_new_protected:Npn \__xsim_exclude_ids:n #1
+  {
+    \seq_clear:N \l__xsim_tmpa_seq
+    \clist_map_inline:nn {#1}
+      {
+        \tl_set:Nx \l__xsim_tmpa_tl
+          { \xsim_get_id_for_property:nn {ID} {##1} }
+        \tl_if_blank:NTF \l__xsim_tmpa_tl
+          { \seq_put_right:Nn \l__xsim_tmpa_seq {##1} }
+          {
+            \seq_put_right:Nx \l__xsim_tmpa_seq
+              { \xsim_get_id_for_property:nn {ID} {##1} }
+          }
+      }
+    \seq_remove_duplicates:N \l__xsim_tmpa_seq
+    \tl_set:Nx \l_xsim_random_exclude_list_tl
+      { \seq_use:Nn \l__xsim_tmpa_seq {,} }
+  }
+
+% use this in the exclude list:
+% \xsim_get_type_for_property:nn {id} {}
+% or a combination of:
+% \xsim_get_type_for_property:nn {ID} {}
+% \xsim_get_id_for_property:nn {ID} {}
+
+% ----------------------------------------------------------------------------
+\tex_endinput:D
diff --git a/Master/texmf-dist/tex/latex/xsim/xsim.solutions.code.tex b/Master/texmf-dist/tex/latex/xsim/xsim.solutions.code.tex
new file mode 100644
index 00000000000..101c19aa23c
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/xsim/xsim.solutions.code.tex
@@ -0,0 +1,402 @@
+% ----------------------------------------------------------------------------
+% the XSIM package - solutions module
+% 
+%   eXercise Sheets IMproved
+% 
+% ----------------------------------------------------------------------------
+% Clemens Niederberger
+% Web:    https://github.com/cgnieder/xsim
+% E-Mail: contact@mychemistry.eu
+% ----------------------------------------------------------------------------
+% Copyright 2017 Clemens Niederberger
+% 
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+% 
+% This work has the LPPL maintenance status `maintained'.
+% 
+% The Current Maintainer of this work is Clemens Niederberger.
+% ----------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% ----------------------------------------------------------------------------
+\XSIMmodule{solutions}{managing solutions}
+
+\xsim_load_modules:n {tags,properties}
+
+\bool_new:N \l_xsim_inside_solution_bool
+\bool_new:N \l__xsim_printsolutions_headings_bool
+\bool_new:N \l__xsim_printsolutions_conditions_bool
+\bool_new:N \l____xsim_this_condition_bool
+
+\prop_new:N \l__xsim_printsolutions_conditions_prop
+
+\int_new:N  \l_xsim_printsolutions_section_int
+\int_new:N  \l_xsim_printsolutions_chapter_int
+
+\tl_new:N   \l__xsim_printsolutions_headings_template_tl
+\tl_new:N   \ExerciseSection
+\tl_new:N   \ExerciseChapter
+\tl_new:N   \l__xsim_printsolutions_collection_tl
+
+% ----------------------------------------------------------------------------
+
+\prg_new_conditional:Npnn \xsim_if_inside_solution: {p,T,F,TF}
+  {
+    \bool_if:NTF \l_xsim_inside_solution_bool
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+\prg_new_conditional:Npnn \xsim_if_solution_print:n #1 {p,T,F,TF}
+  {
+    \bool_if:cTF {l__xsim_#1_solution_print_bool}
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+% #1: type
+% #2: id
+\prg_new_protected_conditional:Npnn \xsim_solution_if_print:nn #1#2 {T,F,TF}
+  {
+    \bool_set_true:N \l____xsim_print_bool
+    \xsim_if_tagged:nnF {#1} {#2}
+      { \bool_set_false:N \l____xsim_print_bool }
+    \xsim_if_boolean_property:nnnF {#1} {#2} {print}
+      { \bool_set_false:N \l____xsim_print_bool }
+    \bool_if:cF {l__xsim_#1_solution_print_bool}
+      { \bool_set_false:N \l____xsim_print_bool }
+    \bool_if:NTF \l____xsim_print_bool
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+\cs_generate_variant:Nn \xsim_solution_if_print:nnT {nV,oo}
+
+% #1: type
+% #2: id
+\prg_new_conditional:Npnn \xsim_if_solution_exists:nn #1#2 {T,F,TF}
+  {
+    \__xsim_set_file_signature:nnn {#1} {#2} {solution}
+    \file_if_exist:VTF \l__xsim_file_path_and_name_tl
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+\cs_generate_variant:Nn \xsim_if_solution_exists:nnT {VV}
+
+% #1: type
+% #2: options
+\cs_new_protected:Npn \xsim_start_solution:nn #1#2
+  {
+    \keys_set:xn { xsim/\xsim_get_parameter:nn {#1} {solution-env} } {#2}
+    \bool_set_true:N \l_xsim_inside_solution_bool
+    \refstepcounter { \xsim_get_parameter:nn {#1} {solution-counter} }
+  }
+
+\cs_new_protected:Npn \xsim_stop_solution:n #1 {}
+
+% ----------------------------------------------------------------------------
+
+% per section condition:
+% #1: type
+% #2: id
+% #3: boolean property
+\prg_new_protected_conditional:Npnn
+  \__xsim_if_solutions_per_section:nnn #1#2#3 {T,F,TF}
+  {
+    \xsim_if_in_list:nnTF {#3} {#1-#2=={true}}
+      {
+        \__xsim_printsolutions_if_condition:nTF {per-section}
+          {
+            \__xsim_printsolutions_condition_true:
+            \xsim_if_in_list:nxTF {section-value}
+              { #1-#2 == { \int_use:N \l_xsim_printsolutions_section_int } }
+              {
+                \tl_set:Nx \ExerciseSection
+                  { \xsim_get_property:nnn {#1} {#2} {section} }
+                \prg_return_true:   
+              }
+              { \prg_return_false: }
+          }
+          { \prg_return_false: }
+      }
+      { \prg_return_false: }
+  }
+
+% per chapter condition:
+% #1: type
+% #2: id
+% #3: boolean property
+\prg_new_protected_conditional:Npnn
+  \__xsim_if_solutions_per_chapter:nnn #1#2#3 {T,F,TF}
+  {
+    \xsim_if_in_list:nnTF {#3} {#1-#2=={true}}
+      {
+        \__xsim_printsolutions_if_condition:nTF {per-chapter}
+          {
+            \__xsim_printsolutions_condition_true:
+            \xsim_if_in_list:nxTF {chapter-value}
+              { #1-#2 == { \int_use:N \l_xsim_printsolutions_chapter_int } }
+              {
+                \tl_set:Nx \ExerciseChapter
+                  { \xsim_get_property:nnn {#1} {#2} {chapter} }
+                \prg_return_true:   
+              }
+              { \prg_return_false: }
+          }
+          { \prg_return_false: }
+      }
+      { \prg_return_false: }
+  }
+
+% per collection condition:
+% #1: type
+% #2: id
+% #3: boolean property
+\prg_new_protected_conditional:Npnn
+  \__xsim_if_solutions_in_collection:nnn #1#2#3 {T,F,TF}
+  {
+    \xsim_if_in_list:nnTF {#3} {#1-#2=={true}}
+      {
+        \__xsim_printsolutions_if_condition:nTF {per-collection}
+          {
+            \__xsim_printsolutions_condition_true:
+            \tl_if_blank:VTF \l__xsim_printsolutions_collection_tl
+              { \prg_return_false: }
+              {
+                \xsim_if_in_collection:VnnTF
+                  \l__xsim_printsolutions_collection_tl
+                  {#1}
+                  {#2}
+                  { \prg_return_true: }
+                  { \prg_return_false: }
+              }
+          }
+          { \prg_return_false: }
+      }
+      { \prg_return_false: }
+  }
+
+% ----------------------------------------------------------------------------
+% conditions mechanism
+\cs_new_protected:Npn \__xsim_printsolutions_condition_false:
+  { \bool_set_false:N \l__xsim_printsolutions_conditions_bool }
+
+\cs_new_protected:Npn \__xsim_printsolutions_condition_true:
+  { \bool_set_true:N \l__xsim_printsolutions_conditions_bool }
+
+% #1: type
+% #2: id
+% #3: boolean property
+\prg_new_conditional:Npnn
+  \__xsim_printsolutions_if_conditions:nnn #1#2#3 {T,F,TF}
+  {
+    \bool_if:NTF \l__xsim_printsolutions_conditions_bool
+      { \prg_return_true: }
+      {
+        \xsim_if_in_list:nnTF {#3} {#1-#2=={true}}
+          { \prg_return_false: }
+          { \prg_return_true: }
+      }
+  }
+
+% #1: name
+% #2: condition
+\cs_new_protected:Npn \__xsim_declare_printsolutions_condition:nn #1#2
+  {
+    \bool_new:c {l__xsim_printsolutions_#1_condition_bool}
+    \prop_put:Nnn \l__xsim_printsolutions_conditions_prop {#1} {#2}
+  }
+
+\prg_new_conditional:Npnn \__xsim_printsolutions_if_condition:n #1 {T,F,TF}
+  {
+    \bool_if:cTF {l__xsim_printsolutions_#1_condition_bool}
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+% #1: name
+% #2: true|false
+\cs_new_protected:Npn \__xsim_printsolutions_condition:nn #1#2
+  { \bool_set_eq:cc {l__xsim_printsolutions_#1_condition_bool} {c_#2_bool} }
+
+% false if any condition is false for this solution:
+% #1: type
+% #2: id
+% #3: boolean property
+\prg_new_protected_conditional:Npnn
+  \__xsim_printsolutions_check_conditions:nnn #1#2#3 {T,F,TF}
+  {
+    \__xsim_printsolutions_condition_false:
+    \bool_set_true:N \l____xsim_this_condition_bool
+    \prop_map_inline:Nn \l__xsim_printsolutions_conditions_prop
+      {
+        \bool_if:cT {l__xsim_printsolutions_##1_condition_bool}
+          {
+            ##2 {#1} {#2} {#3}
+              { }
+              { \bool_set_false:N \l____xsim_this_condition_bool }
+          }
+      }
+    \bool_if:NTF \l____xsim_this_condition_bool
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+
+% #1: type
+% #2: id
+% #3: boolean property
+% #4: code
+\cs_new_protected:Npn \xsim_if_this_solution_do:nnnn #1#2#3#4
+  {
+    \xsim_if_solution_exists:nnT {#1} {#2}
+      { \__xsim_printsolutions_check_conditions:nnnT {#1} {#2} {#3} {#4} }
+  }
+
+% #1: type
+% #2: boolean property
+% #3: code
+\cs_new_protected:Npn \xsim_if_solutions_do:nnn #1#2#3
+  {
+    \xsim_foreach_exercise_type_id:nn {#2}
+      { \xsim_if_this_solution_do:nnnn {#1} {##2} {#2} {#3} }
+  }
+
+% ----------------------------------------------------------------------------
+% #1: boolean -- if true only the solutions of printed exercises will be
+%     output
+% #2: options
+% #3: type
+\cs_new_protected:Npn \xsim_print_type_solutions:nnn #1#2#3
+  {
+    \xsim_verbose:n
+      { Printing~ solutions~ for~ exercise~ type~ `#3'. }
+    \group_begin:
+      \keys_set:nn {xsim/print-solutions} {#2}
+      \bool_set_false:N \l__xsim_tmpa_bool
+      \bool_if:nTF {#1}
+        {
+          \xsim_if_solutions_do:nnn {#3} {print}
+            { \bool_set_true:N \l__xsim_tmpa_bool }
+        }
+        {
+          \xsim_if_solutions_do:nnn {#3} {use}
+            { \bool_set_true:N \l__xsim_tmpa_bool }
+        }
+      \tl_set:Nn \ExerciseType {#3}
+      \bool_if:NT \l__xsim_tmpa_bool
+        {
+          \bool_if:NT \l__xsim_printsolutions_headings_bool
+            {
+              \xsim_use_template:nV
+                {heading}
+                \l__xsim_printsolutions_headings_template_tl
+            }
+        }
+      \bool_if:nTF {#1}
+        {
+          \xsim_if_solutions_do:nnn {#3} {print}
+            { \xsim_insert:nnnn {#3} {##2} {} {solution} }
+        }
+        {
+          \xsim_if_solutions_do:nnn {#3} {use}
+            { \xsim_insert:nnnn {#3} {##2} {} {solution} }
+        }
+    \group_end:
+  }
+
+% #1: boolean -- if true only the solutions of printed exercises will be
+%     output
+% #2: options
+\cs_new_protected:Npn \xsim_print_all_solutions_per_type:nn #1#2
+  {
+    \xsim_foreach_exercise_type:n
+      { \xsim_print_type_solutions:nnn {#1} {#2} {##1} }
+  }
+
+% #1: boolean -- if true only the solutions of printed exercises will be
+%     output
+% #2: options
+\cs_new_protected:Npn \xsim_print_all_solutions_per_id:nn #1#2
+  {
+    \xsim_verbose:n { Printing~ solutions. }
+    \group_begin:
+      \keys_set:nn {xsim/print-solutions} {#2}
+      \bool_set_false:N \l__xsim_tmpa_bool
+      \bool_if:nTF {#1}
+        {
+          \xsim_foreach_exercise_id_type:nn {print}
+            {
+              \xsim_if_this_solution_do:nnnn {##1} {##2} {print}
+                { \xsim_insert:nnnn {##1} {##2} {} {solution} }
+            }
+        }
+        {
+          \xsim_foreach_exercise_id_type:nn {use}
+            {
+              \xsim_if_this_solution_do:nnnn {##1} {##2} {use}
+                { \xsim_insert:nnnn {##1} {##2} {} {solution} }
+            }
+        }
+    \group_end:
+  }
+
+% ----------------------------------------------------------------------------
+
+\__xsim_declare_printsolutions_condition:nn {per-section}
+  { \__xsim_if_solutions_per_section:nnnTF }
+\__xsim_declare_printsolutions_condition:nn {per-chapter}
+  { \__xsim_if_solutions_per_chapter:nnnTF }
+\__xsim_declare_printsolutions_condition:nn {per-collection}
+  { \__xsim_if_solutions_in_collection:nnnTF }
+
+% ----------------------------------------------------------------------------
+
+\keys_define:nn {xsim/print-solutions}
+  {
+    headings .bool_set:N = \l__xsim_printsolutions_headings_bool ,
+    headings .initial:n  = true ,
+    headings-template .tl_set:N  = \l__xsim_printsolutions_headings_template_tl ,
+    headings-template .initial:n = default ,
+    section           .choice: ,
+    section/true      .code:n    =
+      \__xsim_printsolutions_condition:nn  {per-section} {true}
+      \int_set:Nn \l_xsim_printsolutions_section_int { \value {section} } ,
+    section/false     .code:n    =
+      \__xsim_printsolutions_condition:nn  {per-section} {false} ,
+    section/unknown   .code:n    =
+      \__xsim_printsolutions_condition:nn  {per-section} {true}
+      \int_set:Nn \l_xsim_printsolutions_section_int {#1} ,
+    section  .default:n  = true ,
+    section  .initial:n  = false ,
+    chapter           .choice: ,
+    chapter/true      .code:n    =
+      \__xsim_printsolutions_condition:nn  {per-chapter} {true}
+      \int_set:Nn \l_xsim_printsolutions_chapter_int { \value {chapter} } ,
+    chapter/false     .code:n    =
+      \__xsim_printsolutions_condition:nn  {per-chapter} {false} ,
+    chapter/unknown   .code:n    =
+      \__xsim_printsolutions_condition:nn  {per-chapter} {true}
+      \int_set:Nn \l_xsim_printsolutions_chapter_int {#1} ,
+    chapter           .default:n  = true ,
+    chapter           .initial:n  = false ,
+    collection        .choice: ,
+    collection/false  .code:n     =
+      \__xsim_printsolutions_condition:nn  {per-collection} {false} ,
+    collection/unknown .code:n    =
+      \xsim_if_collection_exists:nT {#1}
+        {
+          \__xsim_printsolutions_condition:nn  {per-collection} {true}
+          \tl_set:Nn \l__xsim_printsolutions_collection_tl {#1}
+        } ,
+    collection         .initial:n = false
+  }
+
+% ----------------------------------------------------------------------------
+  
+\tex_endinput:D
diff --git a/Master/texmf-dist/tex/latex/xsim/xsim.sty b/Master/texmf-dist/tex/latex/xsim/xsim.sty
new file mode 100644
index 00000000000..7bc7248c47e
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/xsim/xsim.sty
@@ -0,0 +1,109 @@
+% ----------------------------------------------------------------------------
+% the XSIM package
+% 
+%   eXercise Sheets IMproved
+% 
+% ----------------------------------------------------------------------------
+% Clemens Niederberger
+% Web:    https://github.com/cgnieder/xsim
+% E-Mail: contact@mychemistry.eu
+% ----------------------------------------------------------------------------
+% Copyright 2017 Clemens Niederberger
+% 
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+% 
+% This work has the LPPL maintenance status `maintained'.
+% 
+% The Current Maintainer of this work is Clemens Niederberger.
+% ----------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% ----------------------------------------------------------------------------
+\RequirePackage {expl3,xparse}
+
+\ExplSyntaxOn
+
+\tl_const:Nn \c_xsim_date_tl                 {2017/05/19}
+\tl_const:Nn \c_xsim_version_major_number_tl {0}
+\tl_const:Nn \c_xsim_version_minor_number_tl {8}
+\tl_const:Nn \c_xsim_version_subrelease_tl   {a}
+\tl_const:Nx \c_xsim_version_number_tl
+  {
+    \c_xsim_version_major_number_tl .
+    \c_xsim_version_minor_number_tl
+  }
+\tl_const:Nx \c_xsim_version_tl
+  {
+    \c_xsim_version_number_tl
+    \c_xsim_version_subrelease_tl
+  }
+\tl_const:Nn \c_xsim_info_tl {eXercise ~ Sheets ~ IMproved}
+
+\ProvidesExplPackage
+  {xsim}
+  {\c_xsim_date_tl}
+  {\c_xsim_version_tl}
+  {\c_xsim_info_tl}
+
+% --------------------------------------------------------------------------
+
+% options, information
+  
+\bool_new:N \g_xsim_final_bool
+\bool_new:N \g_xsim_verbose_bool
+\bool_new:N \g_xsim_clear_aux_bool
+
+\keys_define:nn {xsim}
+  {
+    final .bool_gset:N = \g_xsim_final_bool ,
+    verbose .bool_gset:N = \g_xsim_verbose_bool ,
+    clear-aux .bool_gset:N = \g_xsim_clear_aux_bool
+  }
+
+\DeclareOption {final}
+  { \bool_gset_true:N \g_xsim_final_bool }
+
+\DeclareOption {verbose}
+  { \bool_gset_true:N \g_xsim_verbose_bool }
+
+\DeclareOption {clear-aux}
+  { \bool_gset_true:N \g_xsim_clear_aux_bool }
+
+\ProcessOptions \scan_stop:
+
+% --------------------------------------------------------------------------
+
+% messages:
+\msg_new:nnn {xsim} {rerun}
+  {
+    Exercise~ properties~ may~ have~ changed.~ Rerun~ to~ get~ them~
+    synchronized.
+  }
+
+\msg_new:nnn {xsim} {verbose} { #1 ~(\msg_line_context:) }
+
+% --------------------------------------------------------------------------
+
+\bool_new:N \g__xsim_rerun_bool
+
+\cs_new_protected:Npn \xsim_do_rerun:
+  { \xsim_if_rerun:T { \msg_warning:nn {xsim} {rerun} } }
+
+% --------------------------------------------------------------------------
+
+% load module mechanism:
+\tl_set:Nn \l_tmpa_tl {code.tex}
+\@onefilewithoptions {xsim.modules} [][] \l_tmpa_tl
+
+% --------------------------------------------------------------------------
+\xsim_load_modules:n {definitions}
+
+\AtEndDocument { \xsim_do_rerun: }
+
+\tex_endinput:D
diff --git a/Master/texmf-dist/tex/latex/xsim/xsim.tags.code.tex b/Master/texmf-dist/tex/latex/xsim/xsim.tags.code.tex
new file mode 100644
index 00000000000..b438afb203e
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/xsim/xsim.tags.code.tex
@@ -0,0 +1,195 @@
+% ----------------------------------------------------------------------------
+% the XSIM package - tags module
+% 
+%   eXercise Sheets IMproved
+% 
+% ----------------------------------------------------------------------------
+% Clemens Niederberger
+% Web:    https://github.com/cgnieder/xsim
+% E-Mail: contact@mychemistry.eu
+% ----------------------------------------------------------------------------
+% Copyright 2017 Clemens Niederberger
+% 
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+% 
+% This work has the LPPL maintenance status `maintained'.
+% 
+% The Current Maintainer of this work is Clemens Niederberger.
+% ----------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% ----------------------------------------------------------------------------
+\XSIMmodule{tags}{tagging of exercises}
+
+\xsim_load_modules:n {properties}
+
+\seq_new:N \l__xsim_tag_types_seq
+\bool_new:N \l____xsim_tagged_bool
+
+\cs_new_protected:Npn \xsim_set_seq_from_clist:Nn #1#2
+  {
+    \seq_clear:N #1
+    \clist_map_inline:nn {#2}
+      { \tl_if_blank:nF {##1} { \seq_put_right:Nn #1 {##1} } }
+  }
+\cs_generate_variant:Nn \xsim_set_seq_from_clist:Nn {c,Nx}
+
+% #1: name
+\cs_new_protected:Npn \xsim_new_tag_type:n #1
+  {
+    \xsim_verbose:n { Declaring~ new~ tag~ type~ `#1'. }
+    \seq_put_right:Nn \l__xsim_tag_types_seq {#1}
+    \seq_remove_duplicates:N \l__xsim_tag_types_seq
+    \seq_new:c  {l__xsim_chosen_tags_#1_seq}
+    \bool_new:c {l__xsim_ignore_untagged_#1_bool}
+    \bool_new:c {l____xsim_tagged_#1_bool}
+    \keys_define:nn {xsim}
+      {
+        #1/ingore-untagged .bool_set:c = {l__xsim_ignore_untagged_#1_bool} ,
+        #1/ignore-untagged .initial:n  = true ,
+        #1                 .code:n     =
+          \xsim_set_seq_from_clist:cn {l__xsim_chosen_tags_#1_seq} {##1}
+      }
+    \xsim_declare_property:nnnn
+      { \c_false_bool }
+      { \c_false_bool }
+      { \c_false_bool }
+      {#1}
+    \__xsim_declare_printsolutions_condition:nn {#1}
+      { \__xsim_printsolutions_if_tagged:nnnnTF {#1}  }
+    \keys_define:nn {xsim/print-solutions}
+      {
+        #1         .choice: ,
+        #1/false   .code:n    =
+          \__xsim_printsolutions_condition:nn {#1} {false} ,
+        #1/true    .code:n    =
+          \__xsim_printsolutions_condition:nn {#1} {true} ,
+        #1/unknown .code:n    =
+          \keys_set:nn {xsim} { #1 = ##1 }
+          \__xsim_printsolutions_condition:nn {#1} {true} ,
+        #1         .initial:n = false
+      }
+  }
+
+% #1: tag type
+% #2: exercise type
+% #3: id
+% #4: print|use
+\prg_new_protected_conditional:Npnn
+  \__xsim_printsolutions_if_tagged:nnnn #1#2#3#4 {T,F,TF}
+  {
+    \xsim_if_in_list:nnTF {#4} {#2-#3=={true}}
+      {
+        \__xsim_printsolutions_if_condition:nTF {#1}
+          {
+            \__xsim_printsolutions_condition_true:
+            % TODO: doesn't return anything
+            \xsim_if_tagged:nnnTF {#2} {#3} {#1}
+              { \prg_return_true: }
+              { \prg_return_false: }
+          }
+          { \prg_return_false: }
+      }
+      { \prg_return_false: }
+  }
+
+% #1: exercise type
+% #2: id
+% #3: tag type
+\prg_new_protected_conditional:Npnn \xsim_if_tagged:nnn #1#2#3 {T,F,TF}
+  {
+    \bool_set_false:c {l____xsim_tagged_#3_bool}
+    \seq_if_empty:cTF {l__xsim_chosen_tags_#3_seq}
+      { \bool_set_true:c {l____xsim_tagged_#3_bool} }
+      {
+        \xsim_set_seq_from_clist:Nx
+          \l__xsim_tmpa_seq
+          { \xsim_get_property:nnn {#1} {#2} {#3} }
+        \seq_if_empty:NTF \l__xsim_tmpa_seq
+          {
+            \bool_set_eq:cc
+              {l____xsim_tagged_#3_bool}
+              {l__xsim_ignore_untagged_#3_bool}
+          }
+          {
+            \seq_map_inline:Nn \l__xsim_tmpa_seq
+              {
+                \seq_if_in:cnT {l__xsim_chosen_tags_#3_seq} {##1}
+                  {
+                    \bool_set_true:c {l____xsim_tagged_#3_bool}
+                    \seq_map_break:
+                  }
+              }
+          }
+      }
+    \bool_if:cTF {l____xsim_tagged_#3_bool}
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+% #1: exercise type
+% #2: id
+\prg_new_protected_conditional:Npnn \xsim_if_tagged:nn #1#2 {T,F,TF}
+  {
+    \bool_set_true:N \l____xsim_tagged_bool
+    \seq_map_inline:Nn \l__xsim_tag_types_seq
+      {
+        \xsim_if_tagged:nnnF {#1} {#2} {##1}
+          {
+            \bool_set_false:N \l____xsim_tagged_bool
+            \seq_map_break:
+          }
+      }
+    \bool_if:NTF \l____xsim_tagged_bool
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+
+% #1: exercise type
+% #2: id
+% #3: tag type
+% #4: code
+\cs_new_protected:Npn \xsim_foreach_exercise_tag:nnnn #1#2#3#4
+  {
+    \xsim_set_seq_from_clist:Nx \l__xsim_tmpa_seq
+      { \xsim_get_property:nnn {#1} {#2} {#3} }
+    \seq_map_inline:Nn \l__xsim_tmpa_seq {#4}
+  }
+\cs_generate_variant:Nn \xsim_foreach_exercise_tag:nnnn {oo}
+
+% #1: exercise type
+% #2: id
+% #3: tag type
+% #4: sep
+\cs_new_protected:Npn \xsim_exercise_tags_use:nnnn #1#2#3#4
+  {
+    \xsim_set_seq_from_clist:Nx \l__xsim_tmpa_seq
+      { \xsim_get_property:nnn {#1} {#2} {#3} }
+    \seq_use:Nn \l__xsim_tmpa_seq {#4}
+  }
+\cs_generate_variant:Nn \xsim_exercise_tags_use:nnnn {oo}
+
+% #1: exercise type
+% #2: id
+% #3: tag type
+% #4: sep between two
+% #5: sep between more than two
+% #6: sep between last two
+\cs_new_protected:Npn \xsim_exercise_tags_use:nnnnnn #1#2#3#4#5#6
+  {
+    \xsim_set_seq_from_clist:Nx \l__xsim_tmpa_seq
+      { \xsim_get_property:nnn {#1} {#2} {#3} }
+    \seq_use:Nnnn \l__xsim_tmpa_seq {#4} {#5} {#6}
+  }
+\cs_generate_variant:Nn \xsim_exercise_tags_use:nnnn   {oo}
+\cs_generate_variant:Nn \xsim_exercise_tags_use:nnnnnn {oo}
+
+% ----------------------------------------------------------------------------
+\tex_endinput:D
diff --git a/Master/texmf-dist/tex/latex/xsim/xsim.templates.code.tex b/Master/texmf-dist/tex/latex/xsim/xsim.templates.code.tex
new file mode 100644
index 00000000000..f08ff904b4c
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/xsim/xsim.templates.code.tex
@@ -0,0 +1,172 @@
+% ----------------------------------------------------------------------------
+% the XSIM package - templates module
+% 
+%   eXercise Sheets IMproved
+% 
+% ----------------------------------------------------------------------------
+% Clemens Niederberger
+% Web:    https://github.com/cgnieder/xsim
+% E-Mail: contact@mychemistry.eu
+% ----------------------------------------------------------------------------
+% Copyright 2017 Clemens Niederberger
+% 
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+% 
+% This work has the LPPL maintenance status `maintained'.
+% 
+% The Current Maintainer of this work is Clemens Niederberger.
+% ----------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% ----------------------------------------------------------------------------
+\XSIMmodule{templates}{properties of exercises}
+
+\xsim_load_modules:n {base}
+
+\msg_new:nnn {xsim} {unknown-template}
+  {
+    You~ are~ trying~ to~ load~ the~ template~ `#2'~ (template~ type~ `#1')~
+    \msg_line_context: .~ This~ template~ does~ not~ seem~ to~ be~ defined.~
+    I~ am~ using~ the~ template~ `#3'~ (template~ type~ `#1')~ instead.
+  }
+
+% #1: template type
+\cs_new_protected:Npn \xsim_new_template_type:n #1
+  {
+    \xsim_verbose:n { Declaring~ new~ template~ type~ `#1'. }
+    \prop_new:c {l__xsim_#1_template_prop}
+  }
+
+% #1: template type
+% #2: template name
+% #3: code
+\cs_new_protected:Npn \__xsim_add_template:nnn #1#2#3
+  {
+    \xsim_verbose:n { Defining~ new~ template~ `#2'~ of~ type~ `#1'. }
+    \tl_new:c {l__xsim_template_#1_#2_setup_tl}
+    \prop_put:cnn {l__xsim_#1_template_prop} {#2} {#3}
+  }
+
+\prg_new_conditional:Npnn \xsim_if_template_exists:nn #1#2 {T,F,TF}
+  {
+    \prop_if_in:cnTF {l__xsim_#1_template_prop} {#2}
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+% #1: template type
+% #2: template name
+\cs_new_protected:Npn \__xsim_get_template:nn #1#2
+  { \prop_item:cn {l__xsim_#1_template_prop} {#2} }
+
+% ----------------------------------------------------------------------------
+
+% environment templates (types `begin' and `end'):
+\xsim_new_template_type:n {begin}
+\xsim_new_template_type:n {end}
+
+% #1: template name
+% #2: begin code
+% #3: end code
+\cs_new_protected:Npn \xsim_declare_environment_template:nnn #1#2#3
+  {
+    \__xsim_add_template:nnn {begin} {#1}
+      {
+        \__xsim_start_template:nn {begin} {#1}
+        \__xsim_start_template:nn {end} {#1}
+        #2
+      }
+    \__xsim_add_template:nnn {end} {#1}
+      {
+        #3
+        \__xsim_stop_template:nn {end} {#1}
+        \__xsim_stop_template:nn {begin} {#1}
+      }
+  }
+
+% ----------------------------------------------------------------------------
+
+% heading templates for the solution list (type `heading'):
+\xsim_new_template_type:n {heading}
+
+% #1: template name
+% #2: code
+\cs_new_protected:Npn \xsim_declare_heading_template:nn #1#2
+  {
+    \__xsim_add_template:nnn {heading} {#1}
+      {
+        \__xsim_start_template:nn {heading} {#1}
+        #2
+        \__xsim_stop_template:nn {heading} {#1}
+      }
+  }
+
+% ----------------------------------------------------------------------------
+
+% grading table templates (type `table'):
+\xsim_new_template_type:n {table}
+
+% #1: template name
+% #2: code
+\cs_new_protected:Npn \xsim_declare_table_template:nn #1#2
+  {
+    \__xsim_add_template:nnn {table} {#1}
+      {
+        \__xsim_start_template:nn {table} {#1}
+        #2
+        \__xsim_stop_template:nn {table} {#1}
+      }
+  }
+
+% ----------------------------------------------------------------------------
+
+% using templates:
+% setup up the next usage of `template name':
+% #1: template type
+% #2: template name
+% #3: setup code
+\cs_new_protected:Npn \xsim_setup_template:nnn #1#2#3
+  { \tl_set:cn {l__xsim_template_#1_#2_setup_tl} {#3} }
+\cs_generate_variant:Nn \xsim_setup_template:nnn {nnV}
+
+% #1: template type
+% #2: template name
+\cs_new_protected:Npn \__xsim_setup_template:nn #1#2
+  { \tl_use:c {l__xsim_template_#1_#2_setup_tl} }
+
+% #1: template type
+% #2: template name
+\cs_new_protected:Npn \__xsim_clear_template_setup:nn #1#2
+  { \tl_clear:c {l__xsim_template_#1_#2_setup_tl} }
+
+% #1: template type
+% #2: template name
+\cs_new_protected:Npn \__xsim_start_template:nn #1#2
+  { \group_begin: \__xsim_setup_template:nn {#1} {#2} }
+
+% #1: template type
+% #2: template name
+\cs_new_protected:Npn \__xsim_stop_template:nn #1#2
+  { \group_end: \__xsim_clear_template_setup:nn {#1} {#2} }
+  
+% #1: template type
+% #2: template name
+\cs_new_protected:Npn \xsim_use_template:nn #1#2
+  {
+    \xsim_if_template_exists:nnTF {#1} {#2}
+      { \__xsim_get_template:nn {#1} {#2} }
+      {
+        \msg_warning:nnnnn {xsim} {unknown-template} {#1} {#2} {default}
+        \__xsim_get_template:nn {#1} {default}
+      }
+  }
+\cs_generate_variant:Nn \xsim_use_template:nn {nx,nV}
+
+% ----------------------------------------------------------------------------  
+\tex_endinput:D
diff --git a/Master/texmf-dist/tex/latex/xsim/xsim.translations.code.tex b/Master/texmf-dist/tex/latex/xsim/xsim.translations.code.tex
new file mode 100644
index 00000000000..a52d3708632
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/xsim/xsim.translations.code.tex
@@ -0,0 +1,146 @@
+% ----------------------------------------------------------------------------
+% the XSIM package - translations module
+% 
+%   eXercise Sheets IMproved
+% 
+% ----------------------------------------------------------------------------
+% Clemens Niederberger
+% Web:    https://github.com/cgnieder/xsim
+% E-Mail: contact@mychemistry.eu
+% ----------------------------------------------------------------------------
+% Copyright 2017 Clemens Niederberger
+% 
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+% 
+% This work has the LPPL maintenance status `maintained'.
+% 
+% The Current Maintainer of this work is Clemens Niederberger.
+% ----------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% ----------------------------------------------------------------------------
+\XSIMmodule{translations}{language settings for XSIM}
+
+\RequirePackage{translations}
+
+\msg_new:nnn {xsim} {language-not-defined}
+  {
+    You~ chose~ the~ language~ `#1'~ which~ is~ not~ defined~ by~ xsim.~
+    `english'~ is~ used~ instead.~ If~ you~ just~ mistyped~ try~ again!~
+    Otherwise~ contact~ the~ author~ and~ he'll~ probably~ add~ your~ language.
+  }
+
+% --------------------------------------------------------------------------
+
+\bool_new:N      \l__xsim_language_auto_bool
+\bool_set_true:N \l__xsim_language_auto_bool
+% this token list will hold the chosen language for xsim; since the
+% language is either chosen automatically or by option it is only available at
+% begin document
+\tl_new:N  \l_xsim_language_tl
+\tl_set:Nn \l_xsim_language_tl {english}
+\tl_new:N  \l__xsim_current_language_tl
+
+\tl_const:Nn \c__xsim_keyword_prefix_tl {xsim-keyword-}
+
+% ----------------------------------------------------------------------------
+  
+\prop_new:N \g_xsim_translations_prop
+
+% translate the key #1
+\cs_new:Npn \xsim_translate:n #1
+  {
+    \bool_if:NTF \l__xsim_language_auto_bool
+      { \GetTranslation { \c__xsim_keyword_prefix_tl #1 } }
+      {
+        \GetTranslationFor
+          { \l_xsim_language_tl }
+          { \c__xsim_keyword_prefix_tl #1 }
+      }
+  }
+
+\AtBeginDocument{
+  \bool_if:NTF \l__xsim_language_auto_bool
+    {
+      \tl_set:Nx \l_xsim_language_tl
+        { \@trnslt@language{\@trnslt@current@language} }
+    }
+    {
+      \tl_set_eq:NN
+        \l_xsim_language_tl
+        \l__xsim_current_language_tl
+    }   
+}
+
+% ----------------------------------------------------------------------------
+% #1: keyword
+% #2: language
+% #3: translation
+\cs_new_protected:Npn \__xsim_declare_translation:nw #1#2=#3\q_stop
+  {
+    \tl_set:Nx \l__xsim_tmpa_tl { \tl_trim_spaces:n {#2} }
+    \tl_set:Nx \l__xsim_tmpb_tl { \tl_trim_spaces:n {#3} }
+    \xsim_declare_translation:VnV
+      \l__xsim_tmpa_tl
+      {#1}
+      \l__xsim_tmpb_tl
+  }
+
+% #1: language
+% #2: keyword
+% #3: translation
+\cs_new_protected:Npn \xsim_declare_translation:nnn #1#2#3
+  {
+    \xsim_verbose:n
+      { Declaring~ `#1'~ tranlation~ of~ `#2':~ `#3'. }
+    \declaretranslation
+      {#1}
+      { \c__xsim_keyword_prefix_tl #2 }
+      {#3}
+    \prop_gput:Nnn \g_xsim_translations_prop {#2(#1)} {#3}
+  }
+\cs_generate_variant:Nn \xsim_declare_translation:nnn {V,VnV}
+
+% #1: key
+% #2: csv list: { <lang1> = <translation1> , <lang2> = <translation2> }
+\cs_new_protected:Npn \xsim_declare_translations:nn #1#2
+  {
+    \clist_map_inline:nn {#2}
+      { \__xsim_declare_translation:nw {#1} ##1 \q_stop }
+  }
+
+\cs_new:Npn \__xsim_parse_translate_list_entry:nnn #1#2#3 {}
+
+\cs_new_protected:Npn \__xsim_parse_translate_list_entry:www #1(#2)\q_mark#3\q_stop
+  { \__xsim_parse_translate_list_entry:nnn {#1} {#2} {#3} }
+
+\cs_new_protected:Npn \xsim_for_all_translations_do:n #1
+  {
+    \cs_set:Npn \__xsim_parse_translate_list_entry:nnn ##1##2##3 {#1}
+    \prop_map_inline:Nn \g_xsim_translations_prop
+      { \__xsim_parse_translate_list_entry:www ##1 \q_mark ##2 \q_stop }
+  }
+
+% ----------------------------------------------------------------------------
+
+\keys_define:nn {xsim}
+  {
+    language .value_required:n = true ,
+    language .code:n =
+      \tl_if_eq:nnTF {#1} {auto}
+        { \bool_set_true:N \l__xsim_language_auto_bool }
+        {
+          \bool_set_false:N \l__xsim_language_auto_bool
+          \tl_set:Nn \l__xsim_current_language_tl {#1}
+        } ,
+    language .initial:n = auto
+  }
+
+% ----------------------------------------------------------------------------
+\tex_endinput:D
diff --git a/Master/texmf-dist/tex/latex/xsim/xsim.verbwrite.code.tex b/Master/texmf-dist/tex/latex/xsim/xsim.verbwrite.code.tex
new file mode 100644
index 00000000000..ae0338463b1
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/xsim/xsim.verbwrite.code.tex
@@ -0,0 +1,208 @@
+% ----------------------------------------------------------------------------
+% the XSIM package - verbwrite module
+% 
+%   eXercise Sheets IMproved
+% 
+% ----------------------------------------------------------------------------
+% Clemens Niederberger
+% Web:    https://github.com/cgnieder/xsim
+% E-Mail: contact@mychemistry.eu
+% ----------------------------------------------------------------------------
+% Copyright 2017 Clemens Niederberger
+% 
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+% 
+% This work has the LPPL maintenance status `maintained'.
+% 
+% The Current Maintainer of this work is Clemens Niederberger.
+% ----------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% ----------------------------------------------------------------------------
+\XSIMmodule{verbwrite}{write contents of environments verbatim to files}
+
+\xsim_load_modules:n {base}
+
+\iow_new:N  \l__file_contents_iow
+\tl_new:N   \l_xsim_file_begin_tl
+\tl_new:N   \l_xsim_file_end_tl
+\int_new:N  \l_xsim_line_gobble_int
+\int_zero:N \l_xsim_line_gobble_int
+
+\tl_const:Nx \c__xsim_backslash_char_tl { \cs_to_str:N \\ }
+
+\group_begin:
+  \char_set_catcode_other:n {37}
+  \tl_const:Nn \c__xsim_percent_char_tl {%}
+\group_end:
+
+% ----------------------------------------------------------------------------
+
+% the `final' option will prevent writing to files:
+% #1: write stream
+% #2: file name
+\cs_new_protected:Npn \__xsim_open_stream:Nn #1#2
+  {
+    \file_if_exist:nTF {#2}
+      { \xsim_if_final:F { \iow_open:Nn #1 {#2} } }
+      {
+        % \g_xsim_final_bool is a global variable; however, if it is true and
+        % the exercise file doesn't exist, yet, we need to set it locally to
+        % false in order to ensure that the file is correctly written and the
+        % stream closed afterwards
+        \bool_set_false:N \g_xsim_final_bool
+        \iow_open:Nn #1 {#2}
+      }
+  }
+
+% #1: write stream
+\cs_new_protected:Npn \__xsim_close_stream:N #1
+  { \xsim_if_final:F { \iow_close:N #1 } }
+
+% #1: write stream
+% #1: contents
+\cs_new_protected:Npn \__xsim_write_to_stream:Nn #1#2
+  {
+    \xsim_if_final:F
+      {
+        % remove the /one/ space token with catcode 10 that is inserted if
+        % no options are given to the surrounding environment:
+        \tl_set:Nn \l__xsim_tmpa_tl {#2}
+        \tl_remove_once:Nn \l__xsim_tmpa_tl {~}
+        \int_zero:N \l__xsim_tmpa_int
+        \int_while_do:nn { \l__xsim_tmpa_int < \l_xsim_line_gobble_int }
+          {
+            \int_incr:N \l__xsim_tmpa_int
+            \tl_set:Nx \l__xsim_tmpa_tl { \tl_tail:N \l__xsim_tmpa_tl }
+          }
+        \iow_now:NV #1 \l__xsim_tmpa_tl
+      }
+  }
+\cs_generate_variant:Nn \__xsim_write_to_stream:Nn {Nx}
+
+\cs_new:Npn \__xsim_tab: { \c_space_tl \c_space_tl }
+\cs_new:Npn \__xsim_par: { ^^J ^^J }
+
+% the following is inspired by the definition of the `filecontents'
+% environment:
+% #1: boolean - if true an active eol needs to be inserted before
+%               starting to write
+% #2: file name
+\cs_new_protected:Npn \xsim_file_write_start:nn #1#2
+  {
+    % we need to insert an active ^^M if no options are given
+    % see http://tex.stackexchange.com/q/9035/5049 reasons
+    \use:nx
+      { \__xsim_file_write_start:n {#2} }
+      { \bool_if:nF {#1} { \c__xsim_active_eol_tl } }
+  }
+\cs_generate_variant:Nn \xsim_file_write_start:nn {nV}
+
+\group_begin:
+\char_set_catcode_active:n {13} % ^^M (carriage return, endlinechar)
+\char_set_catcode_active:n {12} % ^^L (form feed)
+\char_set_catcode_active:n {9}  % ^^I (horizontal tab)
+%
+\tl_const:Nn \c__xsim_active_eol_tl {^^M} %
+%
+% #1: file name
+\cs_new_protected:Npn \__xsim_file_write_start:n #1 %
+  { %
+    \group_begin: %
+    \xsim_if_final:TF %
+      { \xsim_verbose:x { Not~ (re-)writing~ file~ `#1'. } } %
+      { \xsim_verbose:x { (Re-)writing~ file~ `#1'. } } %
+    \__xsim_open_stream:Nn \l__file_contents_iow {#1} %
+    \tl_if_blank:VF \l_xsim_file_begin_tl %
+      { %
+        \xsim_if_final:F %
+          { %
+            \iow_now:Nx \l__file_contents_iow  %
+              { \l_xsim_file_begin_tl } %
+          } %
+      } %
+    \seq_map_inline:Nn \l_char_special_seq %
+      { \char_set_catcode_other:N ##1 } %
+    \int_step_inline:nnnn {128} {1} {255} %
+      { \char_set_catcode_letter:n {##1} } %
+    \tl_set:Nx \l__xsim_tmpa_tl %
+      { \c__xsim_backslash_char_tl end \cs_to_str:N \{ \@currenvir \cs_to_str:N \} } %
+    \use:x %
+      { %
+        \cs_set:cpn {__xsim_tmpa:www} %
+          ####1 \l__xsim_tmpa_tl %
+          ####2 \l__xsim_tmpa_tl %
+          ####3 \exp_not:N \q_stop: %
+      } %
+        { %
+          \tl_if_blank:nTF {##3} %
+            { \__xsim_write_to_stream:Nn \l__file_contents_iow {##1} } %
+            { %
+              \cs_set:Npx \__xsim_M:w { \exp_not:N \end {\@currenvir} } %
+              \char_set_active_eq:nN {13} \__xsim_M:w %
+              % the last line is `##1 \end{\@currenvir} ##2':
+              % \tl_if_blank:nF {##1} %
+              %   { \__xsim_write_to_stream:Nn \l__file_contents_iow {##1} }%
+              % \tl_if_blank:nF {##2} %
+              %   {}%
+            } %
+          ^^M %
+        } %
+    \char_set_catcode_active:n {13} %
+    \char_set_catcode_active:n {12} %
+    \char_set_catcode_active:n {9} %
+    \cs_set:Npx \__xsim_M:w ##1 ^^M %
+      { %
+        \exp_not:N \__xsim_tmpa:www ##1 %
+        \l__xsim_tmpa_tl %
+        \l__xsim_tmpa_tl %
+        \exp_not:N \q_stop: %
+      } %
+    \char_set_active_eq:nN {13} \__xsim_M:w %
+    \char_set_active_eq:nN {12} \__xsim_par: %
+    \char_set_active_eq:nN {9}  \__xsim_tab: %
+  } %
+\group_end:
+
+\cs_new_protected:Npn \xsim_file_write_stop:
+  {
+    \tl_if_blank:VF \l_xsim_file_end_tl
+      {
+        \xsim_if_final:F
+          {
+            \iow_now:Nx \l__file_contents_iow
+              { \l_xsim_file_end_tl }
+          }
+      }
+    \__xsim_close_stream:N \l__file_contents_iow
+    \group_end:
+  }
+
+% ----------------------------------------------------------------------------
+
+\NewDocumentCommand \XSIMfilewritestart {sm}
+  {
+    \IfBooleanTF {#1}
+      { \xsim_file_write_start:nn { \c_false_bool  } {#2} }
+      { \xsim_file_write_start:nn { \c_true_bool } {#2} }
+  }
+
+\NewDocumentCommand \XSIMfilewritestop {}
+  { \xsim_file_write_stop: }
+
+\NewDocumentCommand \XSIMsetfilebegin {+m}
+  { \tl_set:Nn \l_xsim_file_begin_tl {#1} }
+
+\NewDocumentCommand \XSIMsetfileend {+m}
+  { \tl_set:Nn \l_xsim_file_end_tl {#1} }
+
+\NewDocumentCommand \XSIMgobblechars {m}
+  { \int_set:Nn \l_xsim_line_gobble_int {#1} }
+  
+% ----------------------------------------------------------------------------
diff --git a/Master/texmf-dist/tex/latex/xsim/xsimverb.sty b/Master/texmf-dist/tex/latex/xsim/xsimverb.sty
new file mode 100644
index 00000000000..da6ab48c9ee
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/xsim/xsimverb.sty
@@ -0,0 +1,66 @@
+% ----------------------------------------------------------------------------
+% the XSIMVERB package
+% 
+%   write environments verbatim to files
+% 
+% ----------------------------------------------------------------------------
+% Clemens Niederberger
+% Web:    https://github.com/cgnieder/xsim
+% E-Mail: contact@mychemistry.eu
+% ----------------------------------------------------------------------------
+% Copyright 2017 Clemens Niederberger
+% 
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+% 
+% This work has the LPPL maintenance status `maintained'.
+% 
+% The Current Maintainer of this work is Clemens Niederberger.
+% ----------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% ----------------------------------------------------------------------------
+
+\@ifpackageloaded{xsim}{\endinput}{}
+\RequirePackage {expl3,xparse}
+\ExplSyntaxOn
+
+\tl_const:Nn \c_xsimverb_date_tl                 {2017/03/19}
+\tl_const:Nn \c_xsimverb_version_major_number_tl {0}
+\tl_const:Nn \c_xsimverb_version_minor_number_tl {1}
+\tl_const:Nn \c_xsimverb_version_subrelease_tl   {}
+\tl_const:Nx \c_xsimverb_version_number_tl
+  {
+    \c_xsimverb_version_major_number_tl .
+    \c_xsimverb_version_minor_number_tl
+  }
+\tl_const:Nx \c_xsimverb_version_tl
+  {
+    \c_xsimverb_version_number_tl
+    \c_xsimverb_version_subrelease_tl
+  }
+\tl_const:Nn \c_xsimverb_info_tl {write environments verbatim to files}
+
+\ProvidesExplPackage
+  {xsimverb}
+  {\c_xsimverb_date_tl}
+  {\c_xsimverb_version_tl}
+  {\c_xsimverb_info_tl}
+
+% --------------------------------------------------------------------------
+
+% load module mechanism:
+\tl_set:Nn \l_tmpa_tl {code.tex}
+\@onefilewithoptions {xsim.modules} [][] \l_tmpa_tl
+
+% --------------------------------------------------------------------------
+
+\xsim_load_module:n {verbwrite}
+
+% --------------------------------------------------------------------------
+\tex_endinput:D
diff --git a/Master/tlpkg/bin/tlpkg-ctan-check b/Master/tlpkg/bin/tlpkg-ctan-check
index 4cc40e17c97..54c9760b053 100755
--- a/Master/tlpkg/bin/tlpkg-ctan-check
+++ b/Master/tlpkg/bin/tlpkg-ctan-check
@@ -670,7 +670,7 @@ my @TLP_working = qw(
     xii xifthen xint xits
     xkeyval xlop xltxtra xmltex xmpincl xnewcommand
     xoptarg xpatch xpeek xpiano xpicture xpinyin xprintlen xpunctuate
-    xq xsavebox xskak xstring xtab xunicode
+    xq xsavebox xsim xskak xstring xtab xunicode
     xwatermark xyling xymtex xypic xypic-tut-pt xytree
   yafoot yagusylo yaletter yannisgr yathesis yax
     ycbook ydoc yfonts yfonts-t1 yhmath
diff --git a/Master/tlpkg/libexec/ctan2tds b/Master/tlpkg/libexec/ctan2tds
index 33f0f0d7855..36658036b9b 100755
--- a/Master/tlpkg/libexec/ctan2tds
+++ b/Master/tlpkg/libexec/ctan2tds
@@ -1272,6 +1272,7 @@ chomp ($Build = `cd $Master/../Build/source && pwd`);
  'wsuipa'               => '&PREHOOK_wsuipa',
  'yathesis'		=> '&PREHOOK_flatten1',
  'xepersian'            => '&PREHOOK_flatten1',
+ 'xsim'                 => '&PREHOOK_xsim',
 );
 
 
@@ -1370,6 +1371,7 @@ chomp ($Build = `cd $Master/../Build/source && pwd`);
  'velthuis'		=> '&POSTvelthuis',
  'xecyr'                => '&POSTxecyr',
  'xetex-pstricks'       => '&POSTxetexpstricks',
+ 'xsim'                 => '&POSTxsim',
  'xymtex'               => '&POSTxymtex',
  'zhmetrics'            => '&POSTzhmetrics',
 );
@@ -5316,6 +5318,12 @@ sub PREHOOK_wsuipa {
   &SYSTEM ("$MV changes/* doc/* macros/* mf/* pk/* tfm/* .");
 }
 
+sub PREHOOK_xsim {
+  print "PREHOOK_$package - flatten doc, but not others\n";
+  # we want doc files at top, but keep examples/ and code/ subdirs
+  &SYSTEM ("$MV doc/* .");
+}
+
 
 sub prehook_pod2man {
   my ($author,@scripts) = @_;
@@ -6261,6 +6269,11 @@ sub POSTxetexpstricks {
 #  &mv_with_mkdir ("*", "$DEST/xindy/modules/lang/persian/");
 #}
 
+sub POSTxsim {
+  print "POST$package - move code/ subdir\n";
+  &mv_with_mkdir ("code/*", "$DEST/tex/latex/$package");
+}
+
 sub POSTxymtex {
   print "POST$package - rm .BAK old-doc, move subdirectories\n";
   &SYSTEM ("rm -rf old-doc");
diff --git a/Master/tlpkg/tlpsrc/collection-latexextra.tlpsrc b/Master/tlpkg/tlpsrc/collection-latexextra.tlpsrc
index da0c0fb3e8f..332eda7a22c 100644
--- a/Master/tlpkg/tlpsrc/collection-latexextra.tlpsrc
+++ b/Master/tlpkg/tlpsrc/collection-latexextra.tlpsrc
@@ -1131,6 +1131,7 @@ depend xpeek
 depend xprintlen
 depend xpunctuate
 depend xsavebox
+depend xsim
 depend xstring
 depend xtab
 depend xwatermark
diff --git a/Master/tlpkg/tlpsrc/xsim.tlpsrc b/Master/tlpkg/tlpsrc/xsim.tlpsrc
new file mode 100644
index 00000000000..e69de29bb2d
--- /dev/null
+++ b/Master/tlpkg/tlpsrc/xsim.tlpsrc