% \iffalse
%% File: showkeys.dtx Copyright (C) 1992-1994 David Carlisle
%
%<package>\NeedsTeXFormat{LaTeX2e}
%<package>\ProvidesPackage{showkeys}
%<package>         [1994/01/31 v2.00 Show cite and label keys (DPC)]
%
%<*driver>
\documentclass{ltxdoc}
\usepackage{showkeys}
\GetFileInfo{showkeys.sty}
\begin{document}
\title{The \textsf{showkeys} package\thanks{This file
        has version number \fileversion, last
        revised \filedate.}}
\author{David Carlisle\\carlisle@cs.man.ac.uk}
\date{\filedate}
\maketitle
\DocInput{showkeys.dtx}
\end{document}
%</driver>
% \fi
%
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% \CheckSum{226}
%
%
% \changes{v1.01}{1992/08/25}{Initial version}
% \changes{v1.02}{1994/01/05}
%         {Fix incorrect initialisation (FGBDA19@CC1.KULEUVEN.AC.BE)}
% \changes{v2.00}{1992/01/31}{new version for LaTeX2e}
%
% \section{Introduction}\label{sec:intro}
% |showkeys.sty| modifies the |\label|, |\ref|, |\pageref|, |\cite|, and
% |\bibitem| commands so that the `internal' key is printed. The package
% tries hard to position these labels so that the formatting of the rest
% of the document is unchanged. |\label| and |\bibitem| cause the
% key to appear in a box either in the margin, or in a \TeX\ box of zero
% width, which may possibly over-print other text. The |\ref|,
% |\pageref| and |\cite| commands print their arguments in small type,
% raised just above the line, like this: \ref{sec:intro}.
% Works with |fleqn.sty|.
%
% \changes{v2.00}{1992/01/31}
%         {leqno or ams* may now be loaded after showkeys}
%
% The only other similar package that I could find in the macro index,
% \cite{DMJ:mi}, was |showlabels.sty|, \cite{GN:sl}. After the first
% draft of this package was written, I found \cite{anon:sk} on my local
% installation! I think the current package is more robust than
% \cite{anon:sk}, but I thought that |showkeys| was rather a good name,
% so I have stolen it for this file.
%
% \begin{enumerate}
% \item \label{e^1}This has |\label| immediately after |\item|.
% \item This has the |\label| at the end.\label{e^2}
% \end{enumerate}
%
% \[
% \mbox{A minipage :- }\left\{
% \begin{minipage}{3in}
% Within environments like this |minipage|, We can not use |\marginpar|,
% so the appearance is slightly different. Here is that |enumerate|
% environment again:
%
% \begin{enumerate}
% \item \label{m&e^1}This has |\label| immediately after |\item|.
% \item This has the |\label| at the end.\label{m&e^2}
% \end{enumerate}
% \end{minipage}
% \right.
% \]
%
% Displayed math (without |equation| counter).
% \[0=0\label{disp}\]
%
% Some text refering to the maths on page~\pageref{disp},  and the
% item~\ref{e^1}.
%
% If |showkeys| thinks that the current environment is going to produce
% an ``equation number'', then it does not show the label where the
% |\label| command occurs, but tries to put it in the margin, as shown
% with equation~\ref{eq:xx}.
% The package `knows' about the standard |equation| and |eqnarray|
% environments, and also all the numbered alignment environments offered
% by the AMS\LaTeX\ package, |amstex|.
%
% ^^A (|amstex.sty| must be loaded before |showkeys.sty|
% ^^A for this to work.)
% \changes{v2.00}{1992/01/31}
%         {leqno or ams* may now be loaded after showkeys}
%
% \begin{equation}
% 1=1\label{eq:xx}
% \end{equation}
%
% \begin{eqnarray}
% 2&=&2\label{eqnar:a}\\
% 3&=&3\nonumber\\
% 4&=&4\label{eqnar:b}
% \end{eqnarray}
%
% \begin{figure}[h]
% Within a |figure| environment, the |\label| must not come  before the
% |\caption| command. If you place |\label| inside the argument of
% |\caption| the label will be shown like this:
%
% \caption{Within the caption argument.\label{cap:a}}
%
% If you place |\label| immediately after the |\caption| command it will
% be shown like this:
%
% \caption{Immediately after the caption argument.}\label{cap:b}
%
% If you place the |\label| command at some random point after the
% |\caption| command, it may be shown like:
%
% \caption{In vertical mode not immediately after a box.}
% \vspace{2pt}
%
% \label{cap:c}
% \end{figure}
%
%
% \begin{thebibliography}{9}
%
% \bibitem{GN:sl}
% Gil Neiger, {\em showlabels.sty},
% Undated package, similar to this one, but shows labels
% inline, affecting the formating of the document.
%
% \bibitem{anon:sk}
% Annonymous, {\em showkeys.sty},
% Package, dated 14 May 1988. Very similar to this one,
% also uses |\marginpar| in outer vertical mode.
%
% \bibitem{DMJ:mi}
% David M. Jones, {\em \TeX\ Macro Index},
% A catalogue of \TeX\ macros, including \LaTeX\ packages,
% available from all good \TeX\ archives.
%
% \end{thebibliography}
%
% \StopEventually{}
%
% \section{The Macros}
%
%    \begin{macrocode}
%<*package>
\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{showkeys}
\wlog{Package: showkeys \csname ver@showkeys.sty\endcsname}
%    \end{macrocode}
%
% \changes{v2.00}{1992/01/31}
%         {\cmd{reset@font} is now standard}
%
% \begin{macro}{\SK@label}
% \begin{macro}{\SK@bibitem}
% \begin{macro}{\SK@lbibitem}
% \begin{macro}{\SK@ref}
% \begin{macro}{\SK@pageref}
% \begin{macro}{\SK@citex}
% The saved original definitions
%    \begin{macrocode}
\let\SK@label\label
\let\SK@bibitem\@bibitem
\let\SK@lbibitem\@lbibitem
\let\SK@ref\ref
\let\SK@pageref\pageref
\let\SK@citex\@citex
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\SK@tag@form@}
% \begin{macro}{\SK@eqnnum}
% Saved original definitions of macros that print equation numbers.
%    \begin{macrocode}
\let\SK@tagform@\tagform@
\let\SK@eqnnum\@eqnnum
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\label}
% \begin{macro}{\@bibitem}
% \begin{macro}{\@lbibitem}
% The new definition, print the argument, and then do the old
% definition.
%    \begin{macrocode}
\def\label#1{\@bsphack\SK@\SK@@label{#1}\SK@label{#1}\@esphack}
\def\@bibitem#1{\SK@\SK@@label{#1}\SK@bibitem{#1}\ignorespaces}
\def\@lbibitem[#1]#2{%
  \SK@\SK@@label{#2}\SK@lbibitem[#1]{#2}\ignorespaces}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\SK@}
% Grab hold of |#2| via |\meaning| so characters like |&| and
% |^| do not cause problems later, and pass the result on to the command
% |#1|.
%    \begin{macrocode}
\def\SK@#1#2{\def\@tempa{#2}\expandafter#1\meaning\@tempa\SK@}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\SK@@label}
% Strip off the initial segment of the |\meaning| output, and then put
% the rest either in a |\marginpar| or in a box of size 0pt,
% hopefully not disturbing the surrounding text.
%    \begin{macrocode}
\def\SK@@label#1>#2\SK@{%
%    \end{macrocode}
% Need to work globally as in some cases like alignments, and |fleqn|,
% the counter will be printed in a different group to the |\label|
% command.
%    \begin{macrocode}
  \gdef\SK@lab{\smash{\fbox{\reset@font\small\ttfamily#2}}}%
  \ifvmode
    \ifinner
%    \end{macrocode}
% Because of the contortions of the |list| environment, we might be in
% inner vertical mode if the |\label| immediately follows an |\item|.
% The code for inner vertical mode is mainly optimised for the
% |\caption| command, and would fail miserably here, so use |\mbox| to
% get into horizontal mode, and to give a \meta{box} for |\lastbox| to
% get hold of. Did any one say `kludge'?
%    \begin{macrocode}
      \if@inlabel
        \mbox{}\let\@tempa\SK@lab
                \def\SK@lab{\llap{\@tempa\kern\leftmargin}}%
      \fi
%    \end{macrocode}
% In inner vertical mode, attach the label to the right of the
% immediately preceding box, if it is a box before the current point.
% Otherwise just put it in a box of zero dimensions, with no interline
% skip. (This may slightly move the surrounding text.)
%    \begin{macrocode}
      \setbox\z@=\lastbox
      \ifvoid\z@
        \nointerlineskip\SK@labx
      \else
        \hbox{\box\z@\SK@labx}%
      \fi
    \else
%    \end{macrocode}
% In outer vertical mode, use a |\marginpar|.
%    \begin{macrocode}
      \marginpar{\SK@lab}\SK@lab@relax
    \fi
  \else
%    \end{macrocode}
% If we are in an numbered equation-style environment, do nothing as the
% code to print the number will also print the label, otherwise just
% stick the label at the current point, in a box of zero dimensions.
%    \begin{macrocode}
    \csname SK@\@currenvir\endcsname
    \ifSK@equation\else\SK@labx\fi
  \fi}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\iftagsleft@}
% Make sure that this AMS\LaTeX\ command really is an |\if..|
% \changes{v2.00}{1992/01/31}
%         {Defer tests to begin document}
%    \begin{macrocode}
\AtBeginDocument{%
  \def\@tempa{\let\iftagsleft@\iffalse}%
  \ifx\iftagsleft@\undefined\@tempa\fi%
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\tag@form@}
% \begin{macro}{\eqnnum}
% Perhaps if |leqno| is operative, I should define |\@eqnnum| with the
% `left' version, but it does not really matter.
%    \begin{macrocode}
  \iftagsleft@
    \def\tagform@#1{\llap{\SK@lab\kern\marginparsep}%
                     \SK@lab@relax\SK@tagform@{#1}}%
    \def\@eqnnum{\llap{\SK@lab\kern\displaywidth\kern\marginparsep}%
                     \SK@lab@relax\SK@eqnnum}%
  \else
    \def\tagform@#1{\SK@tagform@{#1}%
                     \rlap{\kern\marginparsep\SK@lab}\SK@lab@relax}%
    \def\@eqnnum{\SK@eqnnum\rlap{\kern\marginparsep\SK@lab}%
                     \SK@lab@relax}%
  \fi}
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\SK@labx}
% Print the label, and then globally reset the print command to
% |\relax|.
%    \begin{macrocode}
\def\SK@labx{\rlap\SK@lab\global\let\SK@lab\relax}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\SK@lab@relax}
% Clear the label.
% \changes{v1.02}{1994/01/05}{Execute to initialise correctly}
%    \begin{macrocode}
\def\SK@lab@relax{\global\let\SK@lab\relax}\SK@lab@relax
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\SK@equation}
% \begin{macro}{\SK@eqnaray}
% \begin{macro}{\SK@align}
% \begin{macro}{\SK@alignat}
% \begin{macro}{\SK@xalignat}
% \begin{macro}{\SK@xxalignat}
% \begin{macro}{\SK@gather}
% \begin{macro}{\SK@multline}
% The following environments print an equation number, so |\label|
% should not print its argument at the point where it appears.
% Note this will fail to show the label if you are in an |eqnarray|
% environment, and use |\label| together with |\nonumber| This might
% just about make sense if you are going to use |\pageref|, but that is
% too bad\ldots
%    \begin{macrocode}
\newif\ifSK@equation
\let\SK@equation\SK@equationtrue
\let\SK@eqnarray\SK@equationtrue
\let\SK@align\SK@equationtrue
\let\SK@alignat\SK@equationtrue
\let\SK@xalignat\SK@equationtrue
\let\SK@xxalignat\SK@equationtrue
\let\SK@gather\SK@equationtrue
\let\SK@multline\SK@equationtrue
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\ref}
% \begin{macro}{\pageref}
% \begin{macro}{\@citex}
% Print the argument with |\SK@@ref|, and then call the original
% definition. then call the original macro.
%    \begin{macrocode}
\def\ref#1{\SK@\SK@@ref{#1}\SK@ref{#1}}
\def\pageref#1{\SK@\SK@@ref{#1}\SK@pageref{#1}}
\def\@citex[#1]#2{\SK@\SK@@ref{#2}\SK@citex[#1]{#2}}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\SK@@ref}
% This is much simpler than the printing of the label, as we know that
% we can be in horizontal mode.
%    \begin{macrocode}
\def\SK@@ref#1>#2\SK@{%
  \leavevmode\vbox to \z@{\vss
    \rlap{\vrule\raise .75em
       \hbox{\underbar{\reset@font\footnotesize\ttfamily#2}}}}}
%    \end{macrocode}
% \end{macro}
%
%    \begin{macrocode}
%</package>
%    \end{macrocode}
%
% \Finale
%

