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From: eijkhout@s41.csrd.uiuc.edu (Victor Eijkhout)
Newsgroups: comp.text.tex
Subject: Re: How do I comment-out a block of TeX
Message-ID: <1991Jan24.160635.14332@csrd.uiuc.edu>
Date: 24 Jan 91 16:06:35 GMT
References: <29555@usc>
Sender: news@csrd.uiuc.edu (news)
Distribution: comp
Organization: UIUC Center for Supercomputing Research and Development
Lines: 60

siemsen@sol.usc.edu (Pete Siemsen) writes:

>Is there some way to comment out a block of TeX code?  Yes, I can

Here is something I wrote, and posted on both usenet and TeXhax
a while ago. It works with plain TeX and LaTeX, and does not
suffer from all of the drawbacks of simpler approaches.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Comment.sty   version 1.0 2 November 1990
% to be used with plain TeX or LaTeX
%
% Author
%    Victor Eijkhout
%    Center for Supercomputing Research and Development
%    University of Illinois at Urbana-Champaign
%    305 Talbot Lab
%    104 South Wright Street
%    Urbana, Illinois 61801, USA
%
%    eijkhout@csrd.uiuc.edu
%
% Usage: all text included in between 
%    \comment ... \endcomment
% or \begin{comment} ... \end{comment}
% is discarded. The closing command should appear on a line
% of its own. No starting spaces, nothing after it.
% This environment should work with arbitrary amounts
% of comment. 
%
% Basic approach: take every line in verbatim mode as macro
% argument, then don't do nothing with.

\def\makeinnocent#1{\catcode`#1=12 }

\def\comment{\begingroup
    \let\do\makeinnocent \dospecials 
    \makeinnocent\^^L % and whatever other special cases
    \endlinechar`\^^M \catcode`\^^M=12 \xcomment}
{\catcode`\^^M=12 \endlinechar=-1 %
 \gdef\xcomment#1^^M{\def\test{#1}
      \ifx\test\plainendcommenttest
          \let\next\endgroup
      \else\ifx\test\lalaendcommenttest
          \def\next{\endgroup\end{comment}}
      \else
          \let\next\xcomment
      \fi \fi \next}
}

{\escapechar=-1
 \xdef\plainendcommenttest{\string\\endcomment}
 \xdef\lalaendcommenttest{\string\\end\string\{comment\string\}}
}

\endinput

Share and enjoy!

Victor.