[latex3-commits] [git/LaTeX3-latex3-latex2e] gh222: Save a csname by using \@swaptoargs (bdd36eb7)

[Johannes Braams]

Repository : https://github.com/latex3/latex2e
On branch  : gh222
Link       : https://github.com/latex3/latex2e/commit/bdd36eb719e448cdfb6bdb4f7e16d042defa6d45

>---------------------------------------------------------------

commit bdd36eb719e448cdfb6bdb4f7e16d042defa6d45
Author: Johannes Braams <texniek at braams.xs4all.nl>
Date:   Mon Jul 6 23:04:01 2020 +0200

    Save a csname by using \@swaptoargs


>---------------------------------------------------------------

bdd36eb719e448cdfb6bdb4f7e16d042defa6d45
 required/tools/verbatim.dtx | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/required/tools/verbatim.dtx b/required/tools/verbatim.dtx
index 339ff891..4a6f8f88 100644
--- a/required/tools/verbatim.dtx
+++ b/required/tools/verbatim.dtx
@@ -506,7 +506,7 @@
 %<*package>
 \NeedsTeXFormat{LaTeX2e}
 \ProvidesPackage{verbatim}
-     [2020-07-05 v1.5t LaTeX2e package for verbatim enhancements]
+     [2020-07-06 v1.5t LaTeX2e package for verbatim enhancements]
 \@ifundefined{verbatim@@@}{}{\endinput}
 %    \end{macrocode}
 %
@@ -1574,21 +1574,25 @@
 %    Then everything is set up as in the |\verbatim| macro. But, as
 %    |\@verbatim| contains a call to |\every at verbatim| which
 %    \emph{might} contain an |\input| statement, which would overwrite
-%    the contents of |\@filef at und|, we need to save that filename
-%    temporarily. 
-% \changes{v1.5s}{2020-06-06}{Save the contents of \cs{@filef at und}
-%    before the call of \cs{@verbatim} (gh/222)}
+%    the contents of |\@filef at und|, we need to save it by expanding it
+%    first. The use of |\@swaptoargs| makes it so that the
+%    \emph{expansion} of |\@filef at und| gets to be the second argument
+%    of |\verbatim at readfile|. 
+% \changes{v1.5t}{2020-07-06}{Expand \cs{@filef at und} before the call
+%    of \cs{@verbatim} (gh/222)}m 
 %    \begin{macrocode}
 \def\verbatim at input#1#2{%
   \IfFileExists {#2}{%
-    \let\@verb at file\@filef at und
-    \@verbatim #1\relax
+    \expandafter\@swaptwoargs\expandafter
+      {\expandafter{\@filef at und}}%
+      {\@verbatim #1\relax
 %    \end{macrocode}
 %    Then it reads in the file, finishes off the \texttt{trivlist}
 %    environment started by |\@verbatim| and closes the group.
 %    This restores everything to its normal settings.
 %    \begin{macrocode}
-    \verbatim at readfile{\@verb at file}\endtrivlist\endgroup\@doendpe}%
+        \verbatim at readfile}
+      \endtrivlist\endgroup\@doendpe}%
 %    \end{macrocode}
 %    If the file is not found a more or less helpful message is
 %    printed. The final |\endgroup| is  needed to close the group