From 026bcd88f082ea4bb3f2ddbac395339309f00a63 Mon Sep 17 00:00:00 2001
From: Norbert Preining <norbert@preining.info>
Date: Fri, 11 Sep 2020 03:02:42 +0000
Subject: CTAN sync 202009110302

---
 macros/latex/contrib/memoir/memoir.dtx | 489 ++++++++++++++++++++++-----------
 1 file changed, 326 insertions(+), 163 deletions(-)

(limited to 'macros/latex/contrib/memoir/memoir.dtx')

diff --git a/macros/latex/contrib/memoir/memoir.dtx b/macros/latex/contrib/memoir/memoir.dtx
index be0f5d3651..3785106482 100644
--- a/macros/latex/contrib/memoir/memoir.dtx
+++ b/macros/latex/contrib/memoir/memoir.dtx
@@ -20,7 +20,7 @@
 % This work consists of the files listed in the README file.
 % 
 % \fi
-% \CheckSum{31157}
+% \CheckSum{31201}
 %
 % \changes{v0.1}{2001/05/20}{First public alpha release}
 % \changes{v0.2}{2001/06/03}{First beta release}
@@ -122,6 +122,7 @@
 %                             inside \cs{IfFileExists} \# needs to be doubled}
 % \changes{v3.7k}{2020/03/25}{Maintenance} 
 % \changes{v3.7l}{2020/06/02}{Small preparation for october kernel update} 
+% \changes{v3.7m}{2020/09/10}{More preparations for october kernel update} 
 %                             
 % \def\dtxfile{memoir.dtx}
 %
@@ -182,6 +183,7 @@
 % \def\fileversion{v3.7j}          \def\filedate{2019/11/21} 
 % \def\fileversion{v3.7k}          \def\filedate{2020/03/25} 
 % \def\fileversion{v3.7l}          \def\filedate{2020/06/02} 
+% \def\fileversion{v3.7m}          \def\filedate{2020/09/10} 
 % \title{The LaTeX \Lpack{memoir} class for configurable book 
 %        typesetting: Source code\thanks{This
 %        file (\texttt{\dtxfile}) has version number \fileversion, last revised
@@ -412,11 +414,11 @@
 %    Announce the name, option files and version for LaTeX2e files:
 %    \begin{macrocode}
 %<class>\ProvidesClass{memoir}%
-%<class>  [2020/06/02 v3.7l configurable book, report, article document class]
+%<class>  [2020/09/10 v3.7m configurable book, report, article document class]
 %    \end{macrocode}
 %  In the manual it is useful to know the current version.
 %    \begin{macrocode}
-%<class>\newcommand\memversion{v3.7l, 2020/06/02}
+%<class>\newcommand\memversion{v3.7m, 2020/09/10}
 %<9pt>\ProvidesFile{mem9.clo}%
 %<9pt>              [2008/01/30 v0.4 memoir class 9pt size option]
 %<10pt>\ProvidesFile{mem10.clo}%
@@ -579,6 +581,26 @@
 % \end{macro}
 % \end{macro}
 %
+% 
+% \changes{v3.7m}{2020/08/05}{Added \cs{IfFormatAtLeastTF}}
+% \begin{macro}{\IfFormatAtLeastTF}
+% Credit to Frank Mittelbach. Using
+% \cs{IfFormatAtLeastTF}\marg{date}\marg{true}\marg{false} we can
+% execute \meta{true} if the format is dated after the given
+% \meta{date} (in {\scriptsize\ttfamily YYYY/MM/DD} format) and
+% \meta{false} otherwise. The main use is for when we get info that
+% certain features are being added to the \LaTeX\ format, features
+% that we want to base class features on. Then this is an easy method
+% for providing the code only avaiable on newer formats and code left
+% over for those still using the older \LaTeX\ formats.\footnote{The \dots TF is a
+% \LaTeX3 convention.}
+%    \begin{macrocode}
+\providecommand\IfFormatAtLeastTF{\@ifl@t@r\fmtversion}
+
+%    \end{macrocode}
+% \end{macro}
+%
+%
 % \begin{macro}{\ifsamename}
 % \begin{macro}{\nametest}
 %    The macro \cs{nametest}\marg{name1}\marg{name2} tests whether the
@@ -878,7 +900,78 @@
 
 %    \end{macrocode}
 % \end{macro}
-% 
+%
+% \noindent
+% From 2020/10/01 format onwards we will implement file hooks via the
+% features provided by the \LaTeX\ kernel. This makes our code easier
+% to do (actually, users really ought to use these hook macros instead
+% of the ones the class provides) and it eliminates the need for us to
+% redefine \cmd{\InputIfFileExists}.
+% \changes{v3.7m}{2020/08/06}{Reimplemented file/package/class hooks}
+%    \begin{macrocode}
+\IfFormatAtLeastTF{2020/10/01}{
+%    \end{macrocode}
+% As mentioned in \cite{LTHOOKS,LTFILEHOOK} the kernel provides hooks
+% at the start of files, packages and classes. The class you implement
+% the latter via our definition of the file hook. We will now instead
+% use the separate hooks. Note that we will \emph{not} be adding any
+% extra labels to these hooks and will provide no interface to do
+% so. If more control is needed, please use the kernel interface directly. 
+% \begin{macro}{\AtBeginFile}
+% \begin{macro}{\AtEndFile}
+% \cs{AtBeginFile}\marg{file}\marg{code} inserts \meta{code}
+% just before \meta{file} is input. Similarly \cs{AtEndFile} inserts
+% just after input.
+%
+% \textbf{Breaking change:} In the old implemenation
+% \verb!\AtEndFile{file}! worked for \texttt{file.tex} even if one
+% did not speficy the extension. Now you will need to use
+% \verb!\AtEndFile{file.tex}! explicitly.
+%    \begin{macrocode}
+  \newcommand\AtBeginFile[2]{\AddToHook{file/before/#1}{#2}}
+  \newcommand\AtEndFile[2]{\AddToHook{file/after/#1}{#2}}
+  
+%    \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \begin{macro}{\AtBeginPackage}
+% \begin{macro}{\AtEndPackage}
+% \begin{macro}{\RequireAtEndPackage}
+% \cs{AtBeginPackage}\marg{pack}\marg{code} inserts \meta{code} 
+% just before the \meta{pack} package is input, and \cs{AtEndPackage}
+% is the equivalent for after input. \cs{RequireAtEndPackage} inserts
+% \meta{code} either at the end of \meta{pack}, or immediately if
+% \meta{pack} has already been input.
+%    \begin{macrocode}
+  \newcommand\AtBeginPackage[2]{\AddToHook{package/before/#1}{#2}}
+  \newcommand\AtEndPackage[2]{\AddToHook{package/after/#1}{#2}}
+  \newcommand{\RequireAtEndPackage}[2]{%
+    \@ifpackageloaded{#1}{#2}{\AtEndPackage{#1}{#2}}}
+  
+%    \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \begin{macro}{\AtBeginClass}
+% \begin{macro}{\AtEndClass}
+% \begin{macro}{\RequireAtEndClass}
+% \cs{AtBeginClass}\marg{class}\marg{code} and friends are the class
+% equivalents of \cs{AtBeginPackage} and friends.
+% \begin{macrocode}
+  \newcommand\AtBeginClass[2]{\AddToHook{class/before/#1}{#2}}
+  \newcommand\AtEndClass[2]{\AddToHook{class/after/#1}{#2}}
+  \newcommand{\RequireAtEndClass}[2]{%
+    \@ifclassloaded{#1}{#2}{\AtEndClass{#1}{#2}}}
+  
+%    \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+%    \begin{macrocode}
+}{% back to the code for older formats
+%    \end{macrocode}
+% \noindent
+% Here follows the old code, which will still be used on older formats:
 %
 %    Code, based on a hint from Morten H{\o}gholm\footnote{CTT posting
 % 2005/11/08, \textit{Re: Checking for packages froma class... 
@@ -913,26 +1006,26 @@
 % \changes{3.7i}{2019/10/22}{Added latest kernel changes, special
 % thanks to Phelype Oleinik}
 %    \begin{macrocode}
-\ifcsname InputIfFileExists \endcsname% looking for an explicit space
-                                % here aka the robust version
-  \DeclareRobustCommand \InputIfFileExists[2]{%
-    \IfFileExists{#1}%
-    {%
-      \expandafter\@swaptwoargs\expandafter
-      {\@filef@und\m@matendf{#1}\killm@matf{#1}}{%
-        #2\@addtofilelist{#1}\m@matbeginf{#1}\@@input%
+  \ifcsname InputIfFileExists \endcsname% looking for an explicit space
+                                  % here aka the robust version
+    \DeclareRobustCommand \InputIfFileExists[2]{%
+      \IfFileExists{#1}%
+      {%
+        \expandafter\@swaptwoargs\expandafter
+        {\@filef@und\m@matendf{#1}\killm@matf{#1}}{%
+          #2\@addtofilelist{#1}\m@matbeginf{#1}\@@input%
+        }%
       }%
-    }%
-  }
-\else
-  % Old definition
-\renewcommand{\InputIfFileExists}[2]{%
-  \IfFileExists{#1}%
-    {#2\@addtofilelist{#1}\m@matbeginf{#1}%
-     \@@input \@filef@und
-     \m@matendf{#1}%
-     \killm@matf{#1}}}
-\fi
+    }
+  \else
+    % Old definition
+    \renewcommand{\InputIfFileExists}[2]{%
+      \IfFileExists{#1}%
+      {#2\@addtofilelist{#1}\m@matbeginf{#1}%
+        \@@input \@filef@und
+        \m@matendf{#1}%
+        \killm@matf{#1}}}
+  \fi
 
 %    \end{macrocode}
 % \end{macro}
@@ -943,10 +1036,10 @@
 % is defined. Similarly \cs{m@matendf}\marg{file} calls
 % \cs{file-m@mfe} if it is defined.
 %    \begin{macrocode}
-\newcommand{\m@matbeginf}[1]{\@ifundefined{#1-m@mfb}{}%
-  {\@nameuse{#1-m@mfb}}}
-\newcommand{\m@matendf}[1]{\@ifundefined{#1-m@mfe}{}%
-  {\@nameuse{#1-m@mfe}}}
+  \newcommand{\m@matbeginf}[1]{\@ifundefined{#1-m@mfb}{}%
+    {\@nameuse{#1-m@mfb}}}
+  \newcommand{\m@matendf}[1]{\@ifundefined{#1-m@mfe}{}%
+    {\@nameuse{#1-m@mfe}}}
 
 %    \end{macrocode}
 % \end{macro}
@@ -955,10 +1048,66 @@
 % \begin{macro}{\killm@matf}
 % \cs{killm@matf}\marg{file} undefines the \cs{file-m@mfb} and
 % \cs{file-m@mfe} macros.
+% ^^A    \begin{macrocode}
+% ^^A  we use the better defintion below
+% ^^A % \newcommand*{\killm@matf}[1]{%
+% ^^A %   \@namelet{#1-m@mfb}\relax
+% ^^A %   \@namelet{#1-m@mfe}\relax}
+% ^^A
+% ^^A   \end{macrocode}
+%
+% ^^A \subsection{Input files into tabulars, and etex}
+%
+%     M.J. Williams (CTT \textit{\cs{noalign} problem with \cs{input} and 
+% tabular in memoir class}, 28 Aug 2007) reported that using \cs{input} in a 
+% tabular resulted in errors. His example was:
+% \begin{verbatim}
+% ...
+% \begin{tabular}{c|c} \hline
+% 1 & 2 \\ \hline
+% \input{data} \hline
+% 5 & 6 \\ \hline
+% \end{tabular}
+% \end{verbatim}
+% where \texttt{data.tex} contains the single line (and no newline) \\
+% \verb?3 & 4 \\?
+%
+% Morten H{\o}gholm noted that the problem
+% was caused by \Lpack{memoir}'s extension to \cs{input}
+% and gave a solution that depends on processing via 
+% \texttt{etex} rather than \texttt{tex}.
+%
+% Here's Morten's fix. Quoting, in part:
+% \begin{quotation}
+%     \Lpack{memoir} extends the file loading mechanism by providing 
+% \cs{AtBeginFile} and \cs{AtEndFile} whose arguments are executed as 
+% the names indicate. \ldots after inputting a file the storage bins are 
+% emptied. The problem [in your case] is that this emptying is an
+% assignment and so starts a new tabular cell and \cs{hline} is only
+% allowed after \verb?\\? or other \cs{hline}s.
+%
+% \ldots the tabular environment wraps each tabular cell in additional
+% groups so one can do an explicit test for which type of group we are in.
+% If tested to be in an align group \emph{and} in vertical mode it means
+% TeX hasn't found something to start a new cell and
+% then \cs{noalign} can be used.
+% \end{quotation}
+%
 %    \begin{macrocode}
-\newcommand*{\killm@matf}[1]{%
-  \@namelet{#1-m@mfb}\relax
-  \@namelet{#1-m@mfe}\relax}
+ %% \ifetex
+  \newcommand*{\killm@matf}[1]{%
+    \ifnum 6=\currentgrouptype
+      \ifvmode
+        \expandafter\expandafter\expandafter\@firstoftwo
+        \expandafter\expandafter\expandafter\noalign
+      \fi
+    \fi
+    \@firstofone
+    {\@namelet{#1-m@mfb}\relax
+     \@namelet{#1-m@mfe}\relax
+    }%
+  }
+ %% \fi
 
 %    \end{macrocode}
 % \end{macro}
@@ -969,12 +1118,12 @@
 % just before \meta{file} is input. Similarly \cs{AtEndFile} inserts
 % just after input.
 %    \begin{macrocode}
-\newcommand{\AtBeginFile}[2]{\@ifundefined{#1-m@mfb}%
-  {\@namedef{#1-m@mfb}{#2}}%
-  {\expandafter\addtodef\csname #1-m@mfb\endcsname{}{#2}}}
-\newcommand{\AtEndFile}[2]{\@ifundefined{#1-m@mfe}%
-  {\@namedef{#1-m@mfe}{#2}}%
-  {\expandafter\addtodef\csname #1-m@mfe\endcsname{}{#2}}}
+  \newcommand{\AtBeginFile}[2]{\@ifundefined{#1-m@mfb}%
+    {\@namedef{#1-m@mfb}{#2}}%
+    {\expandafter\addtodef\csname #1-m@mfb\endcsname{}{#2}}}
+  \newcommand{\AtEndFile}[2]{\@ifundefined{#1-m@mfe}%
+    {\@namedef{#1-m@mfe}{#2}}%
+    {\expandafter\addtodef\csname #1-m@mfe\endcsname{}{#2}}}
 
 %    \end{macrocode}
 % \end{macro}
@@ -989,13 +1138,13 @@
 % \meta{code} either at the end of \meta{pack}, or immediately if
 % \meta{pack} has already been input.
 %    \begin{macrocode}
-\newcommand{\AtBeginPackage}[2]{%
-  \AtBeginFile{#1.\@pkgextension}{#2}}
-\newcommand{\AtEndPackage}[2]{%
-  \AtEndFile{#1.\@pkgextension}{#2}}
-\newcommand{\RequireAtEndPackage}[2]{%
-  \@ifpackageloaded{#1}{#2}%
-  {\AtEndFile{#1.\@pkgextension}{#2}}}
+  \newcommand{\AtBeginPackage}[2]{%
+    \AtBeginFile{#1.\@pkgextension}{#2}}
+  \newcommand{\AtEndPackage}[2]{%
+    \AtEndFile{#1.\@pkgextension}{#2}}
+  \newcommand{\RequireAtEndPackage}[2]{%
+    \@ifpackageloaded{#1}{#2}%
+    {\AtEndFile{#1.\@pkgextension}{#2}}}
 
 %    \end{macrocode}
 % \end{macro}
@@ -1008,19 +1157,22 @@
 % \cs{AtBeginClass}\marg{class}\marg{code} and friends are the class
 % equivalents of \cs{AtBeginPackage} and friends.
 %    \begin{macrocode}
-\newcommand{\AtBeginClass}[2]{%
-  \AtBeginFile{#1.\@clsextension}{#2}}
-\newcommand{\AtEndClass}[2]{%
-  \AtEndFile{#1.\@clsextension}{#2}}
-\newcommand{\RequireAtEndClass}[2]{%
-  \@ifclassloaded{#1}{#2}%
-  {\AtEndFile{#1.\@clsextension}{#2}}}
+  \newcommand{\AtBeginClass}[2]{%
+    \AtBeginFile{#1.\@clsextension}{#2}}
+  \newcommand{\AtEndClass}[2]{%
+    \AtEndFile{#1.\@clsextension}{#2}}
+  \newcommand{\RequireAtEndClass}[2]{%
+    \@ifclassloaded{#1}{#2}%
+    {\AtEndFile{#1.\@clsextension}{#2}}}
 
 %    \end{macrocode}
 % \end{macro}
 % \end{macro}
 % \end{macro}
 %
+%    \begin{macrocode}
+} % end of els part of format check
+%    \end{macrocode}
 %
 %
 %
@@ -18626,61 +18778,6 @@
 %    \end{macrocode}
 %
 %
-% \subsection{Input files into tabulars, and etex}
-%
-%     M.J. Williams (CTT \textit{\cs{noalign} problem with \cs{input} and 
-% tabular in memoir class}, 28 Aug 2007) reported that using \cs{input} in a 
-% tabular resulted in errors. His example was:
-% \begin{verbatim}
-% ...
-% \begin{tabular}{c|c} \hline
-% 1 & 2 \\ \hline
-% \input{data} \hline
-% 5 & 6 \\ \hline
-% \end{tabular}
-% \end{verbatim}
-% where \texttt{data.tex} contains the single line (and no newline) \\
-% \verb?3 & 4 \\?
-%
-% Morten H{\o}gholm noted that the problem
-% was caused by \Lpack{memoir}'s extension to \cs{input}
-% and gave a solution that depends on processing via 
-% \texttt{etex} rather than \texttt{tex}.
-%
-% Here's Morten's fix. Quoting, in part:
-% \begin{quotation}
-%     \Lpack{memoir} extends the file loading mechanism by providing 
-% \cs{AtBeginFile} and \cs{AtEndFile} whose arguments are executed as 
-% the names indicate. \ldots after inputting a file the storage bins are 
-% emptied. The problem [in your case] is that this emptying is an
-% assignment and so starts a new tabular cell and \cs{hline} is only
-% allowed after \verb?\\? or other \cs{hline}s.
-%
-% \ldots the tabular environment wraps each tabular cell in additional
-% groups so one can do an explicit test for which type of group we are in.
-% If tested to be in an align group \emph{and} in vertical mode it means
-% TeX hasn't found something to start a new cell and
-% then \cs{noalign} can be used.
-% \end{quotation}
-%
-%    \begin{macrocode}
-\ifetex
-  \renewcommand*{\killm@matf}[1]{%
-    \ifnum 6=\currentgrouptype
-      \ifvmode
-        \expandafter\expandafter\expandafter\@firstoftwo
-        \expandafter\expandafter\expandafter\noalign
-      \fi
-    \fi
-    \@firstofone
-    {\@namelet{#1-m@mfb}\relax
-     \@namelet{#1-m@mfe}\relax
-    }%
-  }
-\fi
-
-%    \end{macrocode}
-%
 %
 % \subsection{Continuous tabulars}
 %
@@ -30562,18 +30659,35 @@
 % \changes{v1.4}{2003/11/22}{Fiddled \cs{protect} in \cs{trimmaks}
 %                            (from patch v1.7)}              
 % \changes{v3.6h}{2010/12/05}{Added \cs{trimmarkscolor}}
+% \changes{v3.7m}{2020/08/05}{From the 2020/10/01 format, we don't
+% need the \cs{vskip}\texttt{-1in} and \cs{hskip}\texttt{-1in} as the
+% trimmarks are added in a different manner}
 %    \begin{macrocode}
 \newcommand*\trimmarkscolor{}
+%    \end{macrocode}
+% \changes{v3.7m}{2020/08/05}{Factored out two skips}
+% Factoring out two skips to make it easy to remove them in the
+% 2020/10/01 onwards.
+%    \begin{macrocode}
+\newcommand\mem@trimmarks@initial@vskip{\vskip-1in}
+\newcommand\mem@trimmarks@initial@hskip{\hskip-1in}
 \newcommand*{\trimmarks}{%   
-  \vbox to \z@{\vskip-1in \vskip\trimtop % top of logical page
-    \hb@xt@\z@{\hskip-1in
+  \vbox to \z@{%
+    \mem@trimmarks@initial@vskip%
+    \vskip\trimtop % top of logical page
+    \hb@xt@\z@{%
+      \mem@trimmarks@initial@hskip%
       \ifodd\c@page 
-        \hskip\stockwidth \hskip-\trimedge \hskip-\paperwidth
+        \hskip\stockwidth
+        \hskip-\trimedge
+        \hskip-\paperwidth
       \else 
         \if@twoside
           \hskip\trimedge  % left of logical page
         \else
-          \hskip\stockwidth \hskip-\trimedge \hskip-\paperwidth
+          \hskip\stockwidth
+          \hskip-\trimedge
+          \hskip-\paperwidth
         \fi
       \fi
       \vbox to \paperheight{%
@@ -30583,8 +30697,8 @@
         \hb@xt@\paperwidth{\trimmarkscolor\tmarkml\hfil\tmarkmr}%
         \vfil
         \hb@xt@\paperwidth{\trimmarkscolor\tmarkbl\hfil\tmarkbm\hfil\tmarkbr}}%
-    \hss}%
-  \vss}}
+      \hss}%
+    \vss}}
 
 %    \end{macrocode}
 % \end{macro}
@@ -30661,47 +30775,78 @@
     \put(-24,-24){\line(0,1){48}}
     \put(-24,0){\oval(12,12)}
   \end{picture}}}
-\renewcommand*{\trimmarks}{%
-%%  \special{papersize=\the\stockwidth,\the\stockheight}
-  {%
-  \vbox to \z@{\vskip-1in \vskip\trimtop % top of logical page
-    \hb@xt@\z@{\hskip-1in
-      \ifodd\c@page
-        \hskip\stockwidth \hskip-\trimedge \hskip-\paperwidth
-      \else
-        \if@twoside
-          \hskip\trimedge % left of logical page
-        \else
-          \hskip\stockwidth \hskip-\trimedge \hskip-\paperwidth
-        \fi
-      \fi
-      \vbox to \paperheight{%
-        \let\protect\relax %      <- v1.4 addition
+%    \end{macrocode}
+% 
+% \changes{v3.7m}{2020/08/05}{Removed redefinition of \cs{trimmarks}
+% inside \cs{quarkmarks}, it only adds an extra group compared to the
+% normal \cs{trimmarks}}
+% Removed redefintion of \cmd{\trimmarks}, seemingly no need for it.
+%    \begin{macrocode}
+%% \renewcommand*{\trimmarks}{%
+%% %%  \special{papersize=\the\stockwidth,\the\stockheight}
+%%   {%
+%%   \vbox to \z@{\vskip-1in \vskip\trimtop % top of logical page
+%%     \hb@xt@\z@{\hskip-1in
+%%       \ifodd\c@page
+%%         \hskip\stockwidth \hskip-\trimedge \hskip-\paperwidth
+%%       \else
+%%         \if@twoside
+%%           \hskip\trimedge % left of logical page
+%%         \else
+%%           \hskip\stockwidth \hskip-\trimedge \hskip-\paperwidth
+%%         \fi
+%%       \fi
+%%       \vbox to \paperheight{%
+%%         \let\protect\relax %      <- v1.4 addition
 %    \end{macrocode}
 % We remember to add \cs{trimmarkscolor}
 % \changes{v3.6h}{2010/12.05}{added \cs{trimmarkscolor}}
 %    \begin{macrocode}
-        \hb@xt@\paperwidth{\trimmarkscolor\tmarktl\hfil\tmarktm\hfil\tmarktr}%
-        \vfil
-        \hb@xt@\paperwidth{\trimmarkscolor\tmarkml\hfil\tmarkmr}%
-        \vfil
-        \hb@xt@\paperwidth{\trimmarkscolor\tmarkbl\hfil\tmarkbm\hfil\tmarkbr}}%
-      \hss}%
-    \vss}}%
-}}
+%%         \hb@xt@\paperwidth{\trimmarkscolor\tmarktl\hfil\tmarktm\hfil\tmarktr}%
+%%         \vfil
+%%         \hb@xt@\paperwidth{\trimmarkscolor\tmarkml\hfil\tmarkmr}%
+%%         \vfil
+%%         \hb@xt@\paperwidth{\trimmarkscolor\tmarkbl\hfil\tmarkbm\hfil\tmarkbr}}%
+%%       \hss}%
+%%     \vss}}%
+%%   }
+}
 
 %    \end{macrocode}
 % \end{macro}
 % \end{macro}
 %
 %
-%    Any marks are put onto the pages by adding to the \cs{shipout}
+% As of the format update 2020/10/01 a hooking mechanism was added
+% to the kernel. One of these provides a hook into the background of
+% the shipped out pages, ideal for adding trimmarks. This hooking
+% system saves us from messing with \cmd{\shipout} direction (in
+% potentially incompatible ways).
+% 
+% \changes{v3.7m}{2020/08/05}{Applying a format check and adding
+% trimmarks via hook if available}
+%
+% Note that the hook will be named \texttt{memoir/trimmarks} of easy
+% reference if one ever need to do some order readjustments. See
+% \cite{LTHOOKS,LTSHIPOUT} for more details on the hooking system. The
+% extra \cmd{\ifshowtrims} inside the hook is to accommodate for the
+% \cmd{\showtrimson}/\cmd{\showtrimsoff} commands.
+%    \begin{macrocode}
+\IfFormatAtLeastTF{2020/10/01}{
+  \renewcommand\mem@trimmarks@initial@vskip{}
+  \renewcommand\mem@trimmarks@initial@hskip{}
+  \ifshowtrims
+    \AddToHook{shipout/background}[./trimmarks]{\ifshowtrims\put(0,0){\trimmarks}\fi}
+  \fi
+}{
+%    \end{macrocode}
+% Here follows then the old code where Any marks are put onto the pages by adding to the \cs{shipout}
 % routine.
 %
 % \begin{macro}{\mem@oldshipout}
 % Keep a copy of the current version of \cs{shipout} in \cs{mem@oldshipout}.
 %    \begin{macrocode}
-\let\mem@oldshipout\shipout
+  \let\mem@oldshipout\shipout
 %    \end{macrocode}
 % \end{macro}
 %
@@ -30719,13 +30864,13 @@
 % \changes{v1.6180339c}{2009/11/13}{Replaced Dans fix with a fix from
 % Heiko Oberdiek}
 %    \begin{macrocode}
-\newcommand*{\mem@shipi}{%
-  \ifvoid\@cclv\expandafter\aftergroup\fi\mem@shipii}
-\newcommand*\mem@shipii{%
-  \ifvoid\@cclv
-    \mem@oldshipout\box\@cclv
-  \else
-    \ifshowtrims
+  \newcommand*{\mem@shipi}{%
+    \ifvoid\@cclv\expandafter\aftergroup\fi\mem@shipii}
+  \newcommand*\mem@shipii{%
+    \ifvoid\@cclv
+      \mem@oldshipout\box\@cclv
+    \else
+      \ifshowtrims
 %    \end{macrocode}
 % Heiko Oberdiek responded to a problem reported by Rolf
 % Niepraschk. The earlier implementation might cause the output box to
@@ -30740,15 +30885,15 @@
 % Heiko also provided the fix used below. Actually Heikos fix also
 % fixes a problem that might cause glue settings to disappear.
 %    \begin{macrocode}
-    \mem@oldshipout\vbox{%
-        \trimmarks
-        \nointerlineskip
-        \box\@cclv
-     }%
-    \else
-      \mem@oldshipout\box\@cclv
-    \fi
-  \fi}
+      \mem@oldshipout\vbox{%
+          \trimmarks
+          \nointerlineskip
+          \box\@cclv
+       }%
+      \else
+        \mem@oldshipout\box\@cclv
+      \fi
+    \fi}
 %    \end{macrocode}
 % \end{macro}
 % \end{macro}
@@ -30758,13 +30903,15 @@
 % \Lopt{showtrims} option. This adds \cs{mem@shipi} to the page box
 % which then calls the original version of \cs{shipout}.
 %    \begin{macrocode}
-\ifshowtrims
-  \renewcommand*{\shipout}{\afterassignment\mem@shipi\setbox\@cclv=}
-\fi
-
+  \ifshowtrims
+    \renewcommand*{\shipout}{\afterassignment\mem@shipi\setbox\@cclv=}
+  \fi
 %    \end{macrocode}
 % \end{macro}
-%
+%    \begin{macrocode}
+} % end format check, else part
+
+%    \end{macrocode}
 %
 % \section{Verbatims, boxes, and files}
 %
@@ -36471,11 +36618,12 @@
 %    \begin{macrocode}
 %%% revert changes to captioning macros if the caption package is used.
 \AtBeginPackage{caption}{
-  \ClassWarningNoLine{memoir}{%
+  %\ClassWarningNoLine{memoir}{%
+  \ClassInfo{memoir}{%
     For the caption package to function properly with memoir,
-    we will now reset\string\caption\space and friends to
-    kernel defaults and then let the caption package take over.
-    Remember: all caption configuration now goves via the caption
+    we will now reset \string\caption\space and friends to
+    kernel defaults and then let the^^Jcaption package take over.
+    Remember: all caption configuration now goes via the caption
     package interface, not the interface from the memoir class.
     }
 
@@ -36769,7 +36917,7 @@ keyword "\\glossaryentry"
 %
 % \bibitem[GMS94]{GOOSSENS94}
 % Michel Goossens, Frank Mittelbach, and Alexander Samarin.
-% \newblock {\em The LaTeX Companion}.
+% \newblock \emph{The LaTeX Companion}.
 % \newblock Addison-Wesley Publishing Company, 1994.
 %
 %
@@ -36814,6 +36962,21 @@ keyword "\\glossaryentry"
 %  \newblock (Available from CTAN in
 %             \texttt{/macros/latex/required/tools})
 %
+% \bibitem[Mit2020a]{LTFILEHOOK}
+%   Frank Mittelbach
+%   \newblock \emph{The ltfilehook package}
+%    \newblock July 2020. 
+%
+%  \bibitem[Mit2020b]{LTHOOKS}
+%   Frank Mittelbach
+%   \newblock \emph{The lthooks package}
+%    \newblock July 2020. 
+%
+%  \bibitem[Mit2020c]{LTSHIPOUT}
+%   Frank Mittelbach
+%   \newblock \emph{The ltshipout package}
+%    \newblock July 2020. 
+% 
 % \bibitem[Oos96]{FANCYHDR}
 % Piet van Oostrum.
 % \newblock \emph{Page layout in LaTeX}.
-- 
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