Bug#815205: another texinfo.tex bug in \scanmacro

[Gavin Smith]

On 12 April 2016 at 09:05, Norbert Preining <preining at logic.at> wrote:
> Here is a minimal example extracted from the sbcl sources that shows
> the effect:
> \input texinfo   @c -*-texinfo-*-
>
> @iftex
> @macro cl{name}
> {@smallertt at phantom{concurrency:}@llap{cl:}}\name\
> @end macro
> @end iftex
>
> Some text
>
> @tindex @cl{built-in-class}
> foo bar baz
>
> @printindex tp
>
>
> @bye
>

Thanks for sending, I believe the diff below fixes it. Please let me
know whether it works. These catcode changes were there before but I
must have removed them when the expansion of Texinfo macros no longer
took place within a TeX group. They're needed for macro expansion in
index entries, as you found.

Index: texinfo.tex
===================================================================
--- texinfo.tex (revision 7054)
+++ texinfo.tex (working copy)
@@ -5305,7 +5305,6 @@
     \putwordIndexNonexistent
   \else
     \catcode`\\ = 0
-    \escapechar = `\\
     %
     % If the index file exists but is empty, then \openin leaves \ifeof
     % false.  We have to make TeX try to read something from the file, so
@@ -6866,7 +6865,6 @@
   \catcode `\>=\other
   \catcode `\`=\other
   \catcode `\'=\other
-  \escapechar=`\\
   %
   % ' is active in math mode (mathcode"8000).  So reset it, and all our
   % other math active characters (just in case), to plain's definitions.
@@ -7844,15 +7842,27 @@
 % alias because \c means cedilla in @tex or @math
 \let\texinfoc=\c

+\newcount\savedcatcodeone
+\newcount\savedcatcodetwo
+
 % Used at the time of macro expansion.
 % Argument is macro body with arguments substituted
 \def\scanmacro#1{%
   \newlinechar`\^^M
   \def\xeatspaces{\eatspaces}%
   %
+  % Temporarily undo catcode changes of \printindex
+  \savedcatcodeone=\catcode`\@
+  \savedcatcodetwo=\catcode`\\
+  \catcode`\@=0
+  \catcode`\\=\active
+  %
   % Process the macro body under the current catcode regime.
-  \scantokens{#1\texinfoc}\aftermacro%
+  \scantokens{#1 at texinfoc}\aftermacro%
   %
+  \catcode`\@=\savedcatcodeone
+  \catcode`\\=\savedcatcodetwo
+  %
   % The \texinfoc is to remove the \newlinechar added by \scantokens, and
   % can be noticed by \parsearg.
   %   The \aftermacro allows a \comment at the end of the macro definition