%{{{ %M% 1.%I% pdc %E% -- indexing macros

%%Requires: utils.tex

%  This is the interface to the makeindex program

\message{starting index file}
\newwrite\idxfile
\openout\idxfile=\jobname.idx

%  Use Knuth's ^ and ^^ notations.
\newif\ifsilentidx
\def\idxcirk{\ifmmode\def\next{^}\else\let\next=\idxbegin\fi\next}
\def\idxbegin{\futurelet\next\idxbeginswitch}
\def\idxbeginswitch
{%
    \ifx\next\idxcirk
	\let\next=\idxsilent
    \else
	\silentidxfalse 
	\let\next=\idx
    \fi
    \next
}
\catcode`\^=13 \let^=\idxcirk
\macappend\verbatimplains{\\\^}
\def\idxsilent^{\silentidxtrue\idx}

%  ^{foo}  ^|foo|  ^|\foo|  ^<foo>  ^$foo$
\def\idx{\futurelet\next\idxswitch}
\def\idxswitch
{%
    \begingroup
	\ifx\next|%
	    \aftergroup\vidx
	\else\ifx\next\<%
	    \aftergroup\angleidx
	\else\ifx\next$%   $ for bracket matching
	    \aftergroup\mathsidx
	\else\ifx\next"%   $ for bracket matching
	    \aftergroup\quotedidx
	\else
	    \aftergroup\normalidx
	\fi\fi\fi\fi
    \endgroup
}
\def\vidx|%
{%
    \catcode`\\=13 % prevent "\" from forming control sequences
    \futurelet\next\vidxswitch
}
\def\vidxswitch%
{%
    \catcode`\\=0
    \ifx\next\empty	%  ^|\foo|
	\let\next\csidx
    \else		%  ^|foo|
	\let\next\noncsidx
    \fi
    \next
}
{\catcode`\@=0 \catcode`\\=13
@gdef@csidx\#1|%
{%
    @def@next{{@tt@char`@\#1}}%
    @edef@text{#1}%
    @emitidx
}}
\def\noncsidx#1|%
{%
    \def\next{{\tt#1}}%
    \edef\text{#1}%
    \emitidx
}
{\catcode`\@=0 \catcode`\\=13 @gdef\{}}	% make "\" ifx-equivalent to \empty

\def\angleidx\<#1>%
{%
    \def\next{\<#1>}%
    \def\text{#1}%
    \emitidx
}
\def\mathsidx$#1$%
{%
    \def\next{$#1$}%
    \def\text{#1}%
    \emitidx
}
\def\quotedidx"#1"%
{%
    \def\next{""#1""}%
    \def\text{#1}%
    \emitidx
}
\def\normalidx#1%
{%
    \def\text{#1}%
    \let\next=\text
    \emitidx
}

\def\emitidx
{%
    \edef\writeit
      {%
	\write\idxfile{\string\idx{\expandafter\gobbleARROW\meaning\text
	    \ifx\text\next\else 
		@\expandafter\gobbleARROW\meaning\next 
	    \fi}{\noexpand\folio}}%
      }%
    \writeit
    \ifsilentidx \ignorespaces \else \next \fi
}
\def\gobbleARROW#1:->{}

%  The simple case -- write the parameter to the file
\def\index#1{\def\next{#1}\let\text=\next \silentidxtrue\emitidx}
{\plain|
 \gdef\dfnidx#1{\index{#1|idxunderline}}
 \gdef\qdfnidx#1{\index{#1@""#1""|idxunderline}}
}
\def\ttidx#1{^|#1|}

%  Things that go after `|':
\def\idxunderline#1{$\underline{\hbox{#1}}$}
\def\see#1#2{{\it see}\space #1}

%}}} %M%

% Local variables:
% fold-folded-p: t
% tex-macros-p: t
% End: