macroswap (22aug13)

git-svn-id: svn://tug.org/texlive/trunk@31498 c570f23f-e606-0410-a88d-b1316a301751

3 files changed, 74 insertions, 70 deletions

diff --git a/Master/texmf-dist/doc/latex/macroswap/macroswap.pdf b/Master/texmf-dist/doc/latex/macroswap/macroswap.pdf
index 304741e95f1..f6c2c5f8a86 100644
--- a/Master/texmf-dist/doc/latex/macroswap/macroswap.pdf
+++ b/Master/texmf-dist/doc/latex/macroswap/macroswap.pdf
diff --git a/Master/texmf-dist/source/latex/macroswap/macroswap.dtx b/Master/texmf-dist/source/latex/macroswap/macroswap.dtx
index c0fd61c4db1..6853e77d4fb 100644
--- a/Master/texmf-dist/source/latex/macroswap/macroswap.dtx
+++ b/Master/texmf-dist/source/latex/macroswap/macroswap.dtx
@@ -17,7 +17,7 @@
 % \iffalse
 % <package>\NeedsTeXFormat{LaTeX2e}[1999/12/01]
 % <package>\ProvidesPackage{macroswap}
-% <package>   [2013/09/16 v1.0 dtx macro swapper]
+% <package>   [2013/08/21 v1.1 dtx macro swapper]
 %
 %<*driver>
 \documentclass{ltxdoc}
@@ -47,15 +47,18 @@
 %   Grave accent  \`     Left brace    \{     Vertical bar  \|
 %   Right brace   \}     Tilde         \~}
 %
-% \CheckSum{54}
+% \CheckSum{62}
 %
-% \changes{v1.0}{2013/09/18}{Initial version}
+% \changes{v1.0}{2013/08/18}{Initial version}
+% \changes{v1.1}{2013/08/20}{Correct month in version date, remove
+% (unstated) dependency on \texttt{etoolbox} package, support swapping
+% macros that expect parameters, improved error reporting (thanks to
+% Christian Tellechea, Ulrich Diez and Dan)}
 %
 % \GetFileInfo{macroswap.sty}
 %
 % \DoNotIndex{\let, \edef, \xdef, \relax, \newcommand}
 % \DoNotIndex{\csname, \endcsname}
-% \DoNotIndex{\makeatletter, \makeatother}
 %
 % \title{The Macroswap Package\thanks{This document corresponds to \textsf{Macroswap}~\fileversion, dated \filedate.}}
 % \author{Robert J Lee \\ latex@rjlee.homelinux.org}
@@ -136,79 +139,72 @@
 % \section*{Implementation}
 %\StopEventually{\PrintChanges \pagebreak[4] \PrintIndex}
 %
-% First we make the @ symbol a letter so wo can use it internally
-%    \begin{macrocode}
-\makeatletter
-%    \end{macrocode}
-%
 % \begin{macro}{\gmacroswap}
-% given the name of two macros, swap their definitions.
+% Given the name of two macros, swap their definitions.
 % Produces no output.
-% This version is global.
+% This version uses plain |\let| to produce a local assignment.
 %    \begin{macrocode}
-\newcommand{\gmacroswap}[2]{%
+\newcommand{\macroswap}[2]{%
 %    \end{macrocode}
-% NB: we don't use ifcsname, because there's no guarantee that |#1| or
-% |#2| will be a single token
-% |macro@swap@left| and |macro@swap@right| are the contents of the
-% passed-in macro names. The |edef| would normally fully expand its
-% parameter but the |csexpandonce| prevents the full expansion and
-% returns only the token list that we want.
+% NB: there's no guarantee that |#1| or |#2| will be a single token.
+%
+% First verify that they expand to a single macro name:
 %    \begin{macrocode}
-  \edef\macro@swap@left{\csexpandonce{#1}}%
-  \edef\macro@swap@right{\csexpandonce{#2}}%
+  \expandafter\ifcsname#1\endcsname%
+  \else%
+  \PackageError{macrocode}{Two macro names are required for macroswap %
+    (got ``#1'' and ``#2'')}{%
+    Two macro names are required, but the first parameter does not %
+    expand to a defined macro name. Macros have not been swapped.}%
+  \fi%
+  \expandafter\ifcsname#2\endcsname%
+  \else%
+  \PackageError{macrocode}{Two macro names are required for macroswap %
+    (got ``#1'' and ``#2'')}{%
+    Two macro names are required, but the second parameter does not %
+    expand to a defined macro name. Macros have not been swapped.}%
+  \fi%
 %    \end{macrocode}
-% Having taken a copy of the passed-in macro, we then reassign it to
-% the values in our tokens, which we get using |expandonce| to strip
-% off our temporary macro names. Again, |xdef| would normally expand
-% its macros as well as being a global assignment; however, the
-% |expandonce| prevents the full expansion.
-%
-% |expandafter| is used to evaluate the |csname|\dots|\endcsname|
-% become the |xdef|, as |xdef| will only redefine its first parameter.
+% First we use a temporary variable, |macroswap@temp|, to hold the value of the first macro.
+%
+% |\expandafter| is used to evaluate the |\csname|\dots|\endcsname|
+% become the |\let|, as |\let| will only redefine its first parameter.
 %    \begin{macrocode}
-  \expandafter\xdef\csname#2\endcsname{\expandonce{\macro@swap@left}}%
-  \expandafter\xdef\csname#1\endcsname{\expandonce{\macro@swap@right}}%
+  \expandafter\let\expandafter\macroswap@temp\csname#1\endcsname%
 %    \end{macrocode}
 %
-% Finally, we throw away our temporary macros:
+% Next, the same method is used to reassign each passed-in macro.
+% 
+%    \begin{macrocode}
+  \expandafter\let\csname#1\expandafter\endcsname\csname#2\endcsname%
+  \expandafter\let\csname#2\endcsname\macroswap@temp%
+%    \end{macrocode}
+% Finally, we throw away our temporary macro:
 %    \begin{macrocode}
-  \let\macroswap@left\relax%
-  \let\macroswap@right\relax%
+  \let\macroswap@temp\relax%
 }
 %    \end{macrocode}
 % \end{macro}
 %
 % \begin{macro}{\macroswap}
-% given the name of two macros, swap their definitions.
+% Given the name of two macros, swap their definitions.
 % Produces no output.
-% This version is local.
-%    \begin{macrocode}
-\newcommand{\macroswap}[2]{%
-%    \end{macrocode}
-% NB: we don't use ifcsname, because there's no guarantee that |#1| or |#2| will be a single token
+%
+% This version is global; the only difference here is that |\global|
+% is used to modify |\let| to applied globally.
 %    \begin{macrocode}
-  \edef\macro@swap@left{\csexpandonce{#1}}%
-  \edef\macro@swap@right{\csexpandonce{#2}}%
+\newcommand{\gmacroswap}[2]{%
+  \expandafter\let\expandafter\macroswap@temp\csname#1\endcsname%
 %    \end{macrocode}
-% The only difference here is the use of |edef| instead of |xdef|,
-% which expands its second argument and overwrites its first argument
-% locally, so the original values will be restored at the end of the
-% current group or environment.
+% NB: |\expandafter| is used before |\global| so that the |let| becomes global...
 %    \begin{macrocode}
-  \expandafter\edef\csname#2\endcsname{\expandonce{\macro@swap@left}}%
-  \expandafter\edef\csname#1\endcsname{\expandonce{\macro@swap@right}}%
-  \let\macroswap@left\relax%
-  \let\macroswap@right\relax%
+  \expandafter\global\expandafter\let\csname#1\expandafter\endcsname\csname#2\endcsname%
+  \expandafter\global\expandafter\let\csname#2\endcsname\macroswap@temp%
+  \let\macroswap@temp\relax%
 }
 %    \end{macrocode}
 % \end{macro}
 %
-% Leave @ as another character
-%    \begin{macrocode}
-\makeatother
-%    \end{macrocode}
-%
 % That is all
 % \Finale
 \endinput
diff --git a/Master/texmf-dist/tex/latex/macroswap/macroswap.sty b/Master/texmf-dist/tex/latex/macroswap/macroswap.sty
index 6d719cde5a0..cecd5aa8ef7 100644
--- a/Master/texmf-dist/tex/latex/macroswap/macroswap.sty
+++ b/Master/texmf-dist/tex/latex/macroswap/macroswap.sty
@@ -20,24 +20,32 @@
 %% and version 1.2 or later is part of all distributions of
 %% LaTeX version 1999/12/01 or later.
 %% 
-\makeatletter
-\newcommand{\gmacroswap}[2]{%
-  \edef\macro@swap@left{\csexpandonce{#1}}%
-  \edef\macro@swap@right{\csexpandonce{#2}}%
-  \expandafter\xdef\csname#2\endcsname{\expandonce{\macro@swap@left}}%
-  \expandafter\xdef\csname#1\endcsname{\expandonce{\macro@swap@right}}%
-  \let\macroswap@left\relax%
-  \let\macroswap@right\relax%
-}
 \newcommand{\macroswap}[2]{%
-  \edef\macro@swap@left{\csexpandonce{#1}}%
-  \edef\macro@swap@right{\csexpandonce{#2}}%
-  \expandafter\edef\csname#2\endcsname{\expandonce{\macro@swap@left}}%
-  \expandafter\edef\csname#1\endcsname{\expandonce{\macro@swap@right}}%
-  \let\macroswap@left\relax%
-  \let\macroswap@right\relax%
+  \expandafter\ifcsname#1\endcsname%
+  \else%
+  \PackageError{macrocode}{Two macro names are required for macroswap %
+    (got ``#1'' and ``#2'')}{%
+    Two macro names are required, but the first parameter does not %
+    expand to a defined macro name. Macros have not been swapped.}%
+  \fi%
+  \expandafter\ifcsname#2\endcsname%
+  \else%
+  \PackageError{macrocode}{Two macro names are required for macroswap %
+    (got ``#1'' and ``#2'')}{%
+    Two macro names are required, but the second parameter does not %
+    expand to a defined macro name. Macros have not been swapped.}%
+  \fi%
+  \expandafter\let\expandafter\macroswap@temp\csname#1\endcsname%
+  \expandafter\let\csname#1\expandafter\endcsname\csname#2\endcsname%
+  \expandafter\let\csname#2\endcsname\macroswap@temp%
+  \let\macroswap@temp\relax%
+}
+\newcommand{\gmacroswap}[2]{%
+  \expandafter\let\expandafter\macroswap@temp\csname#1\endcsname%
+  \expandafter\global\expandafter\let\csname#1\expandafter\endcsname\csname#2\endcsname%
+  \expandafter\global\expandafter\let\csname#2\endcsname\macroswap@temp%
+  \let\macroswap@temp\relax%
 }
-\makeatother
 \endinput
 %%
 %% End of file `macroswap.sty'.