probsoln 3.01 (22aug11)

git-svn-id: svn://tug.org/texlive/trunk@23668 c570f23f-e606-0410-a88d-b1316a301751

1 files changed, 308 insertions, 139 deletions

diff --git a/Master/texmf-dist/tex/latex/probsoln/probsoln.sty b/Master/texmf-dist/tex/latex/probsoln/probsoln.sty
index fe9a6d3b2b6..365b1075773 100644
--- a/Master/texmf-dist/tex/latex/probsoln/probsoln.sty
+++ b/Master/texmf-dist/tex/latex/probsoln/probsoln.sty
@@ -7,7 +7,7 @@
 %% probsoln.dtx  (with options: `probsoln.sty,package')
 %% 
 %%  probsoln.dtx
-%%  Copyright 2008 Nicola Talbot
+%%  Copyright 2011 Nicola Talbot
 %% 
 %%  This work may be distributed and/or modified under the
 %%  conditions of the LaTeX Project Public License, either version 1.3
@@ -21,7 +21,7 @@
 %% 
 %%  The Current Maintainer of this work is Nicola Talbot.
 %% 
-%%  This work consists of the files probsoln.dtx and probsoln.ins and the derived files probsoln.sty, 1stprncp.tex, args.tex, easy.tex, easy2.tex, implicit.tex, mchoice.tex, newdata.tex, nosoln.tex, probspaces.tex, probspaces2.tex, sample.tex, sample2.tex, sample3.tex, sample4.tex, sample5.tex, tabmchoice.tex.
+%%  This work consists of the files probsoln.dtx and probsoln.ins and the derived files probsoln.sty, sample.tex, sample2.tex, sample3.tex, sample4.tex, sample5.tex, sample6.tex, sample7.tex, prob-1stprncp.tex, prob-args.tex, prob-easy.tex, prob-easy2.tex, prob-implicit.tex, prob-mchoice.tex, prob-mixed.tex, prob-newdata.tex, prob-nosoln.tex, prob-probspaces.tex, prob-probspaces2.tex, prob-tabmchoice.tex.
 %% 
 %% \CharacterTable
 %%  {Upper-case    \A\B\C\D\E\F\G\H\I\J\K\L\M\N\O\P\Q\R\S\T\U\V\W\X\Y\Z
@@ -47,9 +47,8 @@
 %% Display the problems
 %% You may need to change \theenumi back here
 \NeedsTeXFormat{LaTeX2e}
-\ProvidesPackage{probsoln}[2008/08/25 v3.0 (NLCT)]
+\ProvidesPackage{probsoln}[2011/08/22 v3.01 (NLCT)]
 \RequirePackage{ifthen}
-\RequirePackage{substr}
 \RequirePackage{amsmath}
 \newif\ifshowanswers
 \showanswersfalse
@@ -57,6 +56,10 @@
 \let\hideanswers\showanswersfalse
 \DeclareOption{answers}{\showanswerstrue}
 \DeclareOption{noanswers}{\showanswersfalse}
+\newif\ifusedefaultprobargs
+\DeclareOption{usedefaultargs}{\usedefaultprobargstrue}
+\DeclareOption{nousedefaultargs}{\usedefaultprobargsfalse}
+\usedefaultprobargsfalse
 \newcommand*{\prob@showdraftlabel}[2]{}
 \newcommand*{\draftproblemlabel}[2]{[#1,#2]}
 \DeclareOption{draft}{%
@@ -66,10 +69,12 @@
 \ProcessOptions
 \newcommand*{\prob@db@default}{}
 \newcommand*{\prob@databases}{default}
+\newcommand*{\prob@db@default@solutions}{}
 \newcommand*{\prob@newdb}[1]{%
 \@ifundefined{prob@db@#1}{%
   \expandafter\gdef\csname prob@db@#1\endcsname{}%
   \xdef\prob@databases{\prob@databases,#1}%
+  \expandafter\gdef\csname prob@db@#1@solutions\endcsname{}%
   }{%
   \PackageError{probsoln}{Data set `#1' is already defined}{}}}
 \newcommand*{\prob@currentdb}{default}
@@ -127,37 +132,60 @@
     \do@moveargs
   }%
 }
-\newcommand{\prob@newproblem}[4]{%
-\@ifundefined{prob@db@#2}{\prob@newdb{#2}}{}%
-\@ifundefined{prob@data@#2@#3}{%
-\let\@tmp=\undefined
-\newcommand\@tmp[#1]{#4}%
-\expandafter\global\expandafter\let
-   \csname prob@data@#2@#3\endcsname=\@tmp
-\expandafter\xdef\csname prob@argN@#2@#3\endcsname{\number#1}%
-\let\@tmp=\undefined
-\expandafter\ifx\csname prob@db@#2\endcsname\@empty
-  \expandafter\xdef\csname prob@db@#2\endcsname{#3}%
-\else
-  \expandafter\xdef\csname prob@db@#2\endcsname{%
-    \csname prob@db@#2\endcsname,#3}%
-\fi
-\ifnum#1>0\relax
-  \@prob@do@getargs{#1}{#2}{#3}%
-\fi
-  }{%
-  \PackageError{probsoln}{Problem `#3' is already defined for
-  data base `#2'}{Problem labels must be unique for each data base}}%
+\newcommand{\prob@newproblem}[5]{%
+  \@ifundefined{prob@db@#2}{\prob@newdb{#2}}{}%
+  \@ifundefined{prob@data@#2@#3}%
+  {%
+    \let\@tmp=\undefined
+    \newcommand\@tmp[#1]{#4}%
+    \expandafter\global\expandafter\let
+       \csname prob@data@#2@#3\endcsname=\@tmp
+    \expandafter\xdef\csname prob@argN@#2@#3\endcsname{\number#1}%
+    \let\@tmp=\undefined
+    \expandafter\ifx\csname prob@db@#2\endcsname\@empty
+      \expandafter\xdef\csname prob@db@#2\endcsname{#3}%
+    \else
+      \expandafter\xdef\csname prob@db@#2\endcsname{%
+        \csname prob@db@#2\endcsname,#3}%
+    \fi
+    \ifx\@empty#5\@empty
+    \else
+       \edef\thisprob@currentdb{#2}%
+       \edef\thisprob@currentlabel{#3}%
+       \expandafter\@setdefaultprobargs\expandafter{#5}%
+    \fi
+  }%
+  {%
+    \PackageError{probsoln}{Problem `#3' is already defined for
+    data base `#2'}{Problem labels must be unique for each data base}%
+  }%
 }
 \newcommand{\@prob@gobblethree}[3]{}
 \newcommand{\@prob@getargs}[3]{%
 \message{Problem `#3' (in data base `#2') requires #1 argument(s).^^J
-Please specify (e.g. {5}{3}):}%
+Please specify (e.g. \csname @prob@getargs@eg@\romannumeral#1\endcsname):}%
 \read-1to\@tmp
 \expandafter\global\expandafter\let
   \csname prob@args@#2@#3\endcsname=\@tmp
 }
+\def\@prob@getargs@eg@i{{12}}
+\def\@prob@getargs@eg@ii{{5}{3}}
+\def\@prob@getargs@eg@iii{{4}{5}{2}}
+\def\@prob@getargs@eg@iv{{5}{3}{10}{8}}
+\def\@prob@getargs@eg@v{{5}{3}{10}{8}{4}}
+\def\@prob@getargs@eg@vi{{5}{3}{10}{8}{4}{24}}
+\def\@prob@getargs@eg@vii{{5}{3}{10}{8}{4}{24}{32}}
+\def\@prob@getargs@eg@viii{{5}{3}{10}{8}{4}{24}{32}{9}}
+\def\@prob@getargs@eg@ix{{5}{3}{10}{8}{4}{24}{32}{9}{2}}
 \let\@prob@do@getargs\@prob@gobblethree
+\newcommand*{\setprobargs}[3][default]{%
+  \expandafter\gdef\csname prob@args@#1@#2\endcsname{#3}%
+}
+\newcommand*{\@setdefaultprobargs}[1]{%
+  \ifusedefaultprobargs
+    \setprobargs[\thisprob@currentdb]{\thisprob@currentlabel}{#1}%
+  \fi
+}
 \long\def\long@collect@body#1{%
   \@envbody{\@xp#1\@xp{\the\@envbody}}%
   \edef\process@envbody{\the\@envbody\@nx\end{\@currenvir}}%
@@ -167,9 +195,15 @@ Please specify (e.g. {5}{3}):}%
   \edef\process@envbody{\@xp\@nx\csname\@currenvir\endcsname}%
   \process@envbody
 }
-\long\def\long@addto@envbody#1{\global\@envbody\@xp{\the\@envbody#1}}
+\long\def\long@addto@envbody#1{%
+  \toks@{#1}%
+  \edef\@psn@tmp{\the\@envbody\the\toks@}%
+  \global\@envbody\@xp{\@psn@tmp}%
+}
 \long\def\long@collect@@body#1\end#2{%
-  \edef\begin@stack{\long@push@begins#1\begin\end \@xp\@gobble\begin@stack}%
+  \protected@edef\begin@stack{%
+    \long@push@begins#1\begin\end \@xp\@gobble\begin@stack
+  }%
   \ifx\@empty\begin@stack
     \endgroup
     \@checkend{#2}%
@@ -182,22 +216,60 @@ Please specify (e.g. {5}{3}):}%
 \long\def\long@push@begins#1\begin#2{%
   \ifx\end#2\else b\@xp\long@push@begins\fi
 }
-\newenvironment{defproblem}[2][0]{%
-  \def\@prob@currentargN{#1}%
+\newenvironment{defproblem}[1][0]{%
+  \edef\@prob@currentargN{\number0#1}%
+  \@defproblem@beginenv
+}{}
+
+\newcommand*{\@defproblem@beginenv}[2][]{%
+  \def\@prob@currentdefaultargs{#1}%
   \def\@prob@currentlabel{#2}%
   \long@collect@body\prob@do@defproblem
-}{}
+}
 \newcommand{\prob@do@newproblem}[1]{%
-\prob@newproblem\@prob@currentargN\prob@currentdb
-  \@prob@currentlabel{#1}}
+  \prob@newproblem\@prob@currentargN\prob@currentdb
+  \@prob@currentlabel{#1}{\@prob@currentdefaultargs}}
 \let\prob@do@defproblem=\prob@do@newproblem
 \newenvironment{onlysolution}{%
    \long@collect@body\do@onlysolution
 }{}
 \newcommand{\do@onlysolution}[1]{%
-\ifshowanswers
-  #1%
-\fi}
+  \ifshowanswers
+    #1%
+  \fi
+  \@ifundefined{@prob@currentlabel}
+  {}%
+  {%
+    \expandafter
+     \psn@add@unique@label
+       \csname prob@db@\prob@currentdb @solutions\endcsname{%
+         \@prob@currentlabel
+       }%
+  }%
+}
+\newcommand*{\psn@add@unique@label}[2]{%
+  \ifx#1\@empty
+    \xdef#1{#2}%
+  \else
+    \edef\@tmp@label{#2}%
+    \expandafter\DTLifinlist\expandafter{\@tmp@label}{#1}%
+    {}% ignore
+    {\xdef#1{#1,\@tmp@label}}%
+  \fi
+}
+\providecommand{\DTLifinlist}[4]{%
+  \def\@dtl@doifinlist##1,#1,##2\end@dtl@doifinlist{%
+     \def\@before{##1}%
+     \def\@after{##2}%
+  }%
+  \expandafter\@dtl@doifinlist\expandafter,#2,#1,\@nil
+    \end@dtl@doifinlist
+  \ifx\@after\@nnil
+    #4%
+  \else
+    #3%
+  \fi
+}
 \newenvironment{onlyproblem}{%
    \long@collect@body\do@onlyproblem
 }{}
@@ -207,15 +279,20 @@ Please specify (e.g. {5}{3}):}%
   #1%
 \fi}
 \newcommand{\useproblem}[2][default]{%
-\prob@showdraftlabel{#1}{#2}%
-\let\@next=\relax
-\@ifundefined{prob@data@#1@#2}{%
-  \PackageError{probsoln}{Problem `#2' is not defined in data set
-  `#1'}{}%
-}{%
-  \def\@next{\csname prob@data@#1@#2\endcsname}%
-}%
-\@next}
+  \def\@prob@currentlabel{#2}%
+  \def\prob@currentdb{#1}%
+  \prob@showdraftlabel{#1}{#2}%
+  \let\@useprob@next=\relax
+  \@ifundefined{prob@data@#1@#2}%
+  {%
+    \PackageError{probsoln}%
+      {Problem `#2' is not defined in data set `#1'}{}%
+  }%
+  {%
+    \def\@useprob@next{\csname prob@data@#1@#2\endcsname}%
+  }%
+  \@useprob@next
+}
 \newcommand*{\loadallproblems}[2][default]{%
 \bgroup
  \let\par\relax
@@ -224,8 +301,11 @@ Please specify (e.g. {5}{3}):}%
 \egroup
 }
 \newcommand{\prob@do@selectedproblem}[1]{%
-\IfSubStringInString{,\@prob@currentlabel,}{,\prob@selectedlabels,}{%
-\prob@do@newproblem{#1}}{}%
+  \expandafter\DTLifinlist\expandafter{\@prob@currentlabel}{\prob@selectedlabels}%
+  {%
+    \prob@do@newproblem{#1}%
+  }%
+  {}%
 }
 \newcommand{\loadselectedproblems}[3][default]{%
 \bgroup
@@ -236,6 +316,22 @@ Please specify (e.g. {5}{3}):}%
  \input{#3}%
 \egroup
 }
+\newcommand{\prob@do@exceptedproblem}[1]{%
+  \expandafter\DTLifinlist\expandafter{\@prob@currentlabel}{\prob@selectedlabels}%
+  {}%
+  {%
+    \prob@do@newproblem{#1}%
+  }%
+}
+\newcommand{\loadexceptproblems}[3][default]{%
+\bgroup
+ \let\par\relax
+ \edef\prob@currentdb{#1}%
+ \edef\prob@selectedlabels{#2}%
+ \let\prob@do@defproblem=\prob@do@exceptedproblem
+ \input{#3}%
+\egroup
+}
 \newcommand{\prob@add@currentlabel}[1]{%
 \ifx\prob@selectedlabels\@empty
  \xdef\prob@selectedlabels{\@prob@currentlabel}%
@@ -246,6 +342,12 @@ Please specify (e.g. {5}{3}):}%
 \newif\iffirstpass
 \firstpasstrue
 \newcommand{\loadrandomproblems}[3][default]{%
+  \@loadrandomproblems{#1}{#2}{#3}{}%
+}
+\newcommand{\loadrandomexcept}[4][default]{%
+  \@loadrandomproblems{#1}{#2}{#3}{#4}%
+}
+\newcommand{\@loadrandomproblems}[4]{%
 \bgroup
  \let\par\relax
  \def\prob@db@reserved{}%
@@ -256,17 +358,20 @@ Please specify (e.g. {5}{3}):}%
  \input{#3}%
  \@probselN=0\relax
  \@for\@thislabel:=\prob@selectedlabels\do{%
-   \advance\@probselN by 1\relax
-   \expandafter
-     \edef\csname @prob@tmp@\romannumeral\@probselN\endcsname{%
-       \@thislabel}%
+   \expandafter\DTLifinlist\expandafter
+     {\@thislabel}{#4}{}%
+   {%
+     \advance\@probselN by 1\relax
+     \expandafter
+       \edef\csname @prob@tmp@\romannumeral\@probselN\endcsname{%
+         \@thislabel}%
+   }%
  }%
  \shuffle{@prob@tmp@}{\@probselN}%
  \ifnum\@probselN<#2\relax
-   \PackageError{probsoln}{%
-     Can't select \number#2\space\space problem(s):^^J
-     '#3' only contains \number\@probselN\space problem(s)}{%
-     Only \number\@probselN\space problem(s) will be selected}%
+   \PackageWarning{probsoln}{You have requested
+     \number#2\space\space problem(s) but `#3' only contains
+     \number\@probselN\space problems. All problems will be selected}%
  \else
    \@probselN=#2\relax
  \fi
@@ -317,6 +422,33 @@ Please specify (e.g. {5}{3}):}%
   }%
 }%
 }
+\newcommand{\foreachsolution}[2][default]{%
+\@ifundefined{prob@db@#1}{%
+  \PackageError{probsoln}{Data base `#1' is not defined}{}%
+}{%
+  \expandafter\let\expandafter\@tmp\csname prob@db@#1@solutions\endcsname
+  \@for\thisproblemlabel:=\@tmp\do{%
+    \ifx\thisproblemlabel\@empty
+    \else
+      \expandafter\ifnum
+         \csname prob@argN@#1@\thisproblemlabel\endcsname>0\relax
+         \@ifundefined{prob@args@#1@\thisproblemlabel}{%
+           \expandafter\@prob@getargs
+             \csname prob@argN@#1@\thisproblemlabel\endcsname
+             {#1}{\thisproblemlabel}}{}%
+         \expandafter\let\expandafter\thisproblemargs
+           \csname prob@args@#1@\thisproblemlabel\endcsname
+      \else
+         \let\thisproblemargs\@empty
+      \fi
+      \expandafter\toks@\expandafter{\thisproblemargs}%
+      \edef\thisproblem{\noexpand\useproblem[#1]{\thisproblemlabel}%
+         \the\toks@}%
+      #2%
+    \fi
+  }%
+}%
+}
 \newcommand{\foreachdataset}[2]{%
 \@for#1:=\prob@databases\do{#2}}
 \newcount\@probN \newcount\@probselN \newcount\@rndselctr
@@ -324,35 +456,50 @@ Please specify (e.g. {5}{3}):}%
 \newcount\@ps@randtmp
 \r@ndcur=1\relax
 \newcommand*{\PSNrandseed}[1]{%
-\ifnum#1=0\relax
-  \PackageWarning{probsoln}{Can't have 0 as random seed, changing to 1}%
-  \global\r@ndcur=1\relax
-\else
-  \global\r@ndcur=#1\relax
-\fi
-\PackageInfo{probsoln}{Random Seed = \number\r@ndcur}%
+  \ifnum#1=0\relax
+    \PackageWarning{probsoln}{Can't have 0 as random seed, changing to 1}%
+    \global\r@ndcur=1\relax
+  \else
+    \global\r@ndcur=#1\relax
+  \fi
+  \PackageInfo{probsoln}{Random Seed = \number\r@ndcur}%
 }
 \newcommand*{\PSNgetrandseed}[1]{#1=\r@ndcur\relax}
 \newcommand*{\PSNrand}{%
-\@ps@randtmp=\r@ndcur
-\multiply\@ps@randtmp by 16807\relax
-\r@ndcur=\@ps@randtmp
-\global\divide\r@ndcur by 120001\relax
-\global\multiply\r@ndcur by 120001\relax
-\advance\@ps@randtmp by -\r@ndcur
-\global\r@ndcur = \@ps@randtmp
-\ifnum\r@ndcur=0\relax
-  \global\r@ndcur=1\relax
-\fi
+  \@ps@randtmp=\r@ndcur
+  \multiply\@ps@randtmp by 16811\relax
+  \r@ndcur=\@ps@randtmp
+  \global\divide\r@ndcur by 39989\relax
+  \global\multiply\r@ndcur by 39989\relax
+  \advance\@ps@randtmp by -\r@ndcur
+  \global\r@ndcur = \@ps@randtmp
+  \ifnum\r@ndcur=0\relax
+    \global\r@ndcur=1\relax
+  \fi
+}
+\newcommand*{\PSN@old@rand}{%
+  \@ps@randtmp=\r@ndcur
+  \multiply\@ps@randtmp by 16807\relax
+  \r@ndcur=\@ps@randtmp
+  \global\divide\r@ndcur by 120001\relax
+  \global\multiply\r@ndcur by 120001\relax
+  \advance\@ps@randtmp by -\r@ndcur
+  \global\r@ndcur = \@ps@randtmp
+  \ifnum\r@ndcur=0\relax
+    \global\r@ndcur=1\relax
+  \fi
+}
+\newcommand*{\PSNuseoldrandom}{%
+  \let\PSNrand\PSN@old@rand
 }
 \newcommand{\PSNrandom}[2]{%
-\PSNrand
-#1=\r@ndcur
-\@ps@randtmp=\r@ndcur
-\divide\@ps@randtmp by #2\relax
-\multiply\@ps@randtmp by #2\relax
-\advance#1 by -\@ps@randtmp
-\advance#1 by 1\relax
+  \PSNrand
+  #1=\r@ndcur
+  \@ps@randtmp=\r@ndcur
+  \divide\@ps@randtmp by #2\relax
+  \multiply\@ps@randtmp by #2\relax
+  \advance#1 by -\@ps@randtmp
+  \advance#1 by 1\relax
 }
 \newcommand{\random}[3]{%
 \ifnum#2=1\relax
@@ -368,58 +515,73 @@ Please specify (e.g. {5}{3}):}%
 }
 \newcount\@shfctr \newcount\@shfA \newcount\@shfB
 \newcommand{\shuffle}[2]{%
-\@shfctr=1\relax
-\whiledo{\@shfctr < 101}{%
-\PSNrandom{\@shfA}{#2}\PSNrandom{\@shfB}{#2}%
-\ifnum\@shfA=\@shfB
-\else
-  \edef\@@tmpA{\csname#1\romannumeral\@shfA\endcsname}%
-  \let\@tmpA=\@@tmpA
-  \edef\@@tmpB{\csname#1\romannumeral\@shfB\endcsname}%
-  \let\@tmpB=\@@tmpB
-  \expandafter\xdef\csname#1\romannumeral\@shfA\endcsname{\@tmpB}%
-  \expandafter\xdef\csname#1\romannumeral\@shfB\endcsname{\@tmpA}%
-\fi
-\advance\@shfctr by 1\relax
-}%
+  \@shfctr=1\relax
+  \whiledo{\@shfctr < 101}%
+  {%
+    \PSNrandom{\@shfA}{#2}\PSNrandom{\@shfB}{#2}%
+    \ifnum\@shfA=\@shfB
+    \else
+      \edef\@@tmpA{\csname#1\romannumeral\@shfA\endcsname}%
+      \let\@tmpA=\@@tmpA
+      \edef\@@tmpB{\csname#1\romannumeral\@shfB\endcsname}%
+      \let\@tmpB=\@@tmpB
+      \expandafter\xdef\csname#1\romannumeral\@shfA\endcsname{\@tmpB}%
+      \expandafter\xdef\csname#1\romannumeral\@shfB\endcsname{\@tmpA}%
+    \fi
+    \advance\@shfctr by 1\relax
+  }%
 }
 \newcount\@ps@forrand
 \newcommand{\doforrandN}[4]{%
-{\@ps@forrand=0\relax
-\@for#2:=#3\do{%
-\advance\@ps@forrand by 1\relax
-\expandafter\edef\csname @doforrandN@\romannumeral\@ps@forrand\endcsname{#2}}%
-\ifnum\@ps@forrand<#1\relax
-\PackageError{probsoln}{Can't randomly select \number#1 item(s)}{You
-have requested \number#1 item(s), but there
-are only \number\@ps@forrand item(s) in the list}%
-\else
-\shuffle{@doforrandN@}{\@ps@forrand}%
-\ifnum#1>0\relax
-\@ps@forrand=0\relax
-\loop
-\advance\@ps@forrand by 1\relax
-\edef#2{\csname @doforrandN@\romannumeral\@ps@forrand\endcsname}%
-#4%
-\ifnum\@ps@forrand<#1\relax
-\repeat
-\fi
-\fi
-}}
+  {%
+    \@ps@forrand=0\relax
+    \@for#2:=#3\do{%
+      \advance\@ps@forrand by 1\relax
+      \expandafter
+        \edef\csname @doforrandN@\romannumeral\@ps@forrand\endcsname{#2}%
+    }%
+    \ifnum\@ps@forrand<#1\relax
+      \PackageError{probsoln}{Can't randomly select \number#1 item(s)}{You
+      have requested \number#1 item(s), but there
+      are only \number\@ps@forrand item(s) in the list}%
+    \else
+      \shuffle{@doforrandN@}{\@ps@forrand}%
+      \ifnum#1>0\relax
+        \@ps@forrand=0\relax
+        \loop
+          \advance\@ps@forrand by 1\relax
+          \edef#2{\csname @doforrandN@\romannumeral\@ps@forrand\endcsname}%
+           #4%
+        \ifnum\@ps@forrand<#1\relax
+        \repeat
+      \fi
+    \fi
+  }%
+}
 \newcommand*{\newproblem}{\@ifstar\@snewproblem\@newproblem}
-\newcommand{\@snewproblem}[3][0]{%
-\begin{defproblem}[#1]{#2}%
-#3%
-\end{defproblem}}
-\newcommand{\@newproblem}[4][0]{%
-\begin{defproblem}[#1]{#2}%
-#3%
-\begin{onlysolution}%
-\begin{solution}%
-#4%
-\end{solution}%
-\end{onlysolution}%
-\end{defproblem}}
+\newcommand{\@snewproblem}[1][0]{%
+  \def\@newprob@argN{#1}%
+  \@s@newproblem
+}%
+\newcommand{\@s@newproblem}[3][]{%
+  \begin{defproblem}[\@newprob@argN][#1]{#2}%
+    #3%
+  \end{defproblem}%
+}
+\newcommand{\@newproblem}[1][0]{%
+  \def\@newprob@argN{#1}%
+  \@ns@newproblem
+}
+\newcommand{\@ns@newproblem}[4][]{%
+  \begin{defproblem}[\@newprob@argN][#1]{#2}%
+    #3%
+    \begin{onlysolution}%
+      \begin{solution}%
+        #4%
+      \end{solution}%
+    \end{onlysolution}%
+  \end{defproblem}%
+}
 \newcommand*{\selectallproblems}[1]{{\loadallproblems[#1]{#1}}%
 \foreachproblem[#1]{\PSNitem\thisproblem\endPSNitem}}
 \newcommand*{\selectrandomly}[2]{%
@@ -428,21 +590,28 @@ are only \number\@ps@forrand item(s) in the list}%
 }
 \newenvironment{PSNitem}{\item}{}
 \@ifundefined{solution}{%
-\newenvironment{solution}{\par\noindent\textbf{\solutionname:}}{}%
+  \newenvironment{solution}{\par\noindent\textbf{\solutionname:}\space
+    \ignorespaces}{}%
 }{}
 \newcommand*{\solutionname}{Solution}
 \newenvironment{textenum}{%
-\ifnum\@enumdepth>\thr@@
-  \@toodeep
-\else
-  \advance\@enumdepth\@ne
-  \edef\@enumctr{enum\romannumeral\the\@enumdepth}%
-  \let\@item\@textitem
-  \def\@itemlabel{\refstepcounter{\@enumctr}%
-    \csname label\@enumctr\endcsname}%
-  \setcounter{\@enumctr}{0}%
-\fi\ignorespaces}{%
-\global\advance\@enumdepth\m@ne}
+  \ifnum\@enumdepth>\thr@@
+    \@toodeep
+  \else
+    \advance\@enumdepth\@ne\relax
+    \edef\@enumctr{enum\romannumeral\the\@enumdepth}%
+    \let\@item\@textitem
+    \def\@itemlabel{%
+      \refstepcounter{\@enumctr}%
+      \csname label\@enumctr\endcsname
+    }%
+    \setcounter{\@enumctr}{0}%
+  \fi
+  \ignorespaces
+}%
+{%
+  \global\advance\@enumdepth\m@ne\relax
+}
 \def\@textitem[#1]{#1\space\ignorespaces}
 \newcommand*{\correctitemformat}[1]{\fbox{#1}}
 \newcommand*{\incorrectitemformat}[1]{%