indexing4ht.4ht

\@ifpackageloaded{imakeidx}{%
	\makeatletter
	\newcommand\:wrindex[3]{%
	  \edef\th@idx@entry{\detokenize{#2}}
		\imki@wrindexentry{#1}{\th@idx@entry}{#3}
	}
	\makeatother
}{%ToDo: Provide configuration for index writing without imakeidx
	\newcommand\:wrindex[3]{}
}

% because imakeidx has support for multiple indices, we need to select a
% right one
\NewConfigure{indexname}{1}
% default index name is \jobname

% configure variable which is saved on every index call
% section mark is used by default, other possible values may be paragraphs, or
% links to individual index entries
\NewConfigure{indexvalue}{1}
\Configure{indexvalue}{\getCurrentSectionNumber}
\NewConfigure{indexidentifier}{1}
\Configure{indexidentifier}{\CurSecHaddr}

% we need to suppress adding of multiple identical identifiers
\edef\curseccnt{}
\renewcommand\index[2][]{%
  \ifx|#1|%
     \Configure{indexname}{\jobname}%
   \else\Configure{indexname}{#1}%
	 \fi%
  \:wrindex{\a:indexname}{#2}{\a:indexvalue}
  \edef\newseccnt{sec\a:indexvalue}
	% save identifier only if it haven't been used yet
  \ifx\newseccnt\curseccnt\else%
    \Tag{sec\a:indexvalue}{\a:indexidentifier}
  \fi%
  \let\curseccnt\newseccnt
}

% print index locators. make links to destinations in document
\newcommand\idxlocator[1]{%
\ifTag{sec#1}{\a:locatorlink{\Ref{sec#1}}{}#1\b:locatorlink}{#1}%
%\ifTag{sec#1}{\Link{\Ref{sec#1}}{}#1\EndLink}{#1}%
\typeout{\LikeRef{sec#1}}
}

\NewConfigure{locatorlink}{2}
\Configure{locatorlink}{\Link}{\EndLink}

% to support crossreferencess, we save index keyword with unique identifier

\GetTitleStringSetup{expand}
\GetTitleStringDisableCommands{%
  \renewcommand\LaTeX{LaTeX}
}

\newcount\idxkwdcnt
\LinkCommand\IdxKWLink{span,href,id}
\newcommand\idxkeyword[1]{%
  \global\advance\idxkwdcnt by 1\relax%
  % use tags only one time
  \GetTitleString{#1}
  \ifcsdef{idxkw\GetTitleStringResult}{}%
  %{\Tag{idxkw#1}{idxkw\the\idxkwdcnt}}%
  {\expandafter\Tag\expandafter{idxkw\GetTitleStringResult}{idxkw\the\idxkwdcnt}}%
  \csgdef{idxkw\GetTitleStringResult}{x}
  \a:IdxKW{}{idxkw\the\idxkwdcnt}#1\b:IdxKW
}


\NewConfigure{IdxKW}{2}
\Configure{IdxKW}{\IdxKWLink}{\EndIdxKWLink}

  
\renewcommand\see[1]{%
  \GetTitleString{#1}%
  \a:see\ \ifTag{idxkw#1}{\a:seeLink{\Ref{idxkw\GetTitleStringResult}}{}#1\b:seeLink}{#1}
}  

% make link configurable, in order to enable user to add custom parameters
\NewConfigure{seeLink}{2}
\Configure{seeLink}{\Link}{\EndLink}

\NewConfigure{see}{1}
\Configure{see}{\textit{see}}

\renewcommand\seealso[1]{%
  \GetTitleString{#1}%
  \a:seealso\ \ifTag{idxkw#1}{\a:seeAlsoLink{\Ref{idxkw\GetTitleStringResult}}{}#1\b:seeAlsoLink}{#1}
}

\NewConfigure{seeAlsoLink}{2}
\Configure{seeAlsoLink}{\Link}{\EndLink}

\NewConfigure{seealso}{1}
\Configure{seealso}{\textit{see also}}