%%
%% citebackref.sty, version 0.1, 23 May 1996.
%%
%% For use with LaTeX
%% Copyright (C) 1996 by John Maraist, all rights reserved
%%
%% This code is freely distributable in its entirety, and is made
%% available to you under the GNU General License. 
%%
%% Purpose of package:
%% To record the pages where citation to specific bibliographic
%% entries are made in a LaTeX document.
%% 
%% Interface:
%% For a bibliographic entry with label L, the command 
%%   \citebackrefpages{L}
%% will generate the list of pages where a that entry has been \cite'd to
%% that point in a document, removing duplicate page numbers.
%% 
%% Parameters:
%% The four commands below control the formatting of the page printout.
%% All can be (relatively) safely redefined.
%% 
%%   \citebackrefpageundefined
%%   Expanded when the given label is undefined.
%%   Default: {?}
%% 
%%   \citebackrefpageempty
%%   Expanded when the label is defined, but not used.
%%   Default: {}
%% 
%%   \citebackrefpageleader
%%   Expanded before the list of pages.
%%   Default: {: p.\,}
%% 
%%   \citebackrefpageseparator
%%   Expanded between each pages in the list.
%%   Default: {,\penalty\@m\,}
%%   The "\penalty\@m" part allows a line break.
%% 
%% Limitations:
%% (1) The \citebackrefpages{L} command prints only uses between the
%% beginning of the document and the invocation of the command:
%% subsequent references are not mentioned.  A future revision will
%% instead use a pass through the .aux file.
%% (2) This is a LaTeX hack, not a BibTeX hack.  If you use BibTeX to
%% generate your bibliography, you must either (a) hand-edit your final
%% bibliography or (b) modify your BibTeX style file.  Maybe one day I'll
%% make standard edits to a few .bst files, but not today...
%% (3) Only references using \cite will be noticed.
%%

%% Default customizable behavior
\def\citebackrefpageundefined{?}
\def\citebackrefpageempty{}
\def\citebackrefpageleader{: p.\,}
\def\citebackrefpageseparator{,\penalty\@m\,}

%% Debugging options.  Uncomment the redefinitions of these commands
%% to generate debugging information in the LaTeX interactive output.
\def\@@ncEncodeDebug#1{}
\def\@@ncDecodeDebug#1{}
%\def\@@ncEncodeDebug#1{\typeout{#1}}
%\def\@@ncDecodeDebug#1{\typeout{#1}}

%% Save the definitions of some existing commands.  Hopefully, we can
%% be as compatible as possible with other packages.
\let\@@oldcite=\cite
\let\@@bibitem=\bibitem
\let\@@biblabel=\@biblabel

%% The main routine and loop.
\def\@noteciteone#1%
{\@@ncEncodeDebug{ Running noteciteone with #1 on page \arabic{page}.}%
 \@ifundefined{last@#1}%
   {\expandafter\xdef\csname last@#1\endcsname{-100}%
    \@@ncEncodeDebug{ Set last@#1 to \@nameuse{last@#1}.}}%
   {\@@ncEncodeDebug{ Did not initialize last@#1, set to \@nameuse{last@#1}.}%
    }%
 \@ifundefined{cited@#1}%
   {\@@ncEncodeDebug{ First definition of cited@#1 to \arabic{page}.}%
    \expandafter\xdef\csname cited@#1\endcsname{\arabic{page}}}%
   {\ifnum\@nameuse{last@#1}=\thepage%
 	\@@ncEncodeDebug{ Last use \@nameuse{last@#1} same as current page \thepage, skipping with cited@#1 as \@nameuse{cited@#1}.}%
    \else%
 	\expandafter\xdef\csname cited@#1\endcsname%
			 {\@nameuse{cited@#1}%
				   \citebackrefpageseparator\arabic{page}}%
 	\@@ncEncodeDebug{ Reset cited@#1 to \@nameuse{cited@#1}.}%
    \fi}%
 \expandafter\xdef\csname last@#1\endcsname{\thepage}}
%% Loop.
\def\notecite#1{\@for\@notecitetemp:=#1%
\do{\@ifundefined{b@\@notecitetemp}%
    {\@@ncEncodeDebug{b@\@notecitetemp undefined, skipping to next.}}%
	    {\@@ncEncodeDebug{Calling noteciteone with b@\@notecitetemp.}%
	     \edef\@NCtemp{\@nameuse{b@\@notecitetemp}}%
	     \@noteciteone{\@NCtemp}}}}

%% Output interface.
\def\citebackrefpages#1%
{\@@ncDecodeDebug{Called citebackrefpages with #1}%
	\@ifundefined{cited@\@nameuse{b@#1}}%
	{\citebackrefpageundefined%
	 \@@ncDecodeDebug{ b@#1 undefined; exiting.}}
	{\@ifundefined{cited@\@nameuse{b@#1}}%
	 {\citebackrefpageempty%
	  \@@ncDecodeDebug{ cited@\@nameuse{b@#1} undefined; exiting.}}%
	 {\@@ncDecodeDebug{ cited@\@nameuse{b@#1} defined; proceeding.}%
	 \citebackrefpageleader\@nameuse{cited@\@nameuse{b@#1}}}}}

%% Redefinition of \cite.  
\def\@newcitewithoutoptional#1{\notecite{#1}\@@oldcite{#1}}
\def\@newcitewithoptional[#1]#2{\notecite{#2}\@@oldcite[#1]{#2}}
\def\cite{\@ifnextchar [{\@newcitewithoptional}{\@newcitewithoutoptional}}

 % \def\@biblabel#1{\@ifundefined{cited@#1}%
 % 		{[#1]}%
 % 		{[#1\@ifundefined{backrefeditlabels}{}%
 % 			{\citebackrefpageleader\@nameuse{cited@#1}}]}}