% \iffalse meta-comment
%
% Copyright (C) 2008 by Ulrich M. Schwarz
%
% This file may be distributed and/or modified under the conditions of
% the LaTeX Project Public License, version 1.3a.
% The license can be obtained from
% http://www.latex-project.org/lppl/lppl-1-3a.txt
%
% \fi
%
%\iffalse (hide this from DocInput)
%<*driver>
\documentclass{ltxdoc}

\usepackage[T1]{fontenc}
\usepackage{fourier}
\usepackage[scaled=0.8]{helvet}
\usepackage{luximono}

\usepackage{amsmath, amsthm}
\usepackage{thm-restate}
\newtheorem{lemma}{Lemma}
\providecommand\pkg{\textsf}
\GetFileInfo{thm-restate.sty}
\EnableCrossrefs
\CodelineIndex
\RecordChanges
\begin{document}

 \newcommand\thmrestate{\textsf{thm-restate}}
 \title{The \thmrestate\ package\thanks{%
   This file documents version~\fileversion\ of~\filedate,
   RCS ${}$Id: thm-restate.dtx,v 1.12 2008/03/09 20:06:09 ulmi Exp ${}$.
 }}
 \author{Ulrich M. Schwarz\thanks{ulmi@absatzen.de}}

 \maketitle

\begin{abstract}
  This package provides one single environment, restatable, which lets you
  repeat whole theorems without retyping them.
\end{abstract}

  \DocInput{thm-restate.dtx}
\end{document}
%</driver>
%<*restate>
%\fi
%
% \CharacterTable
% {Upper-case \A\B\C\D\E\F\G\H\I\J\K\L\M\N\O\P\Q\R\S\T\U\V\W\X\Y\Z
% Lower-case \a\b\c\d\e\f\g\h\i\j\k\l\m\n\o\p\q\r\s\t\u\v\w\x\y\z
% Digits \0\1\2\3\4\5\6\7\8\9
% Exclamation \! Double quote \" Hash (number) \#
% Dollar \$ Percent \% Ampersand \&
% Acute accent \' Left paren \( Right paren \)
% Asterisk \* Plus \+ Comma \,
% Minus \- Point \. Solidus \/
% Colon \: Semicolon \; Less than \<
% Equals \= Greater than \> Question mark \?
% Commercial at \@ Left bracket \[ Backslash \\
% Right bracket \] Circumflex \^ Underscore \_
% Grave accent \` Left brace \{ Vertical bar \|
% Right brace \} Tilde \~}
% \CheckSum{160}
%
% \DoNotIndex{\@for,\addtocounter,\arabic,\csname,\endcsname,\cup,\CurrentOption}
% \DoNotIndex{\{,\},\do,\define@key,\def,\DeclareOption,\else,\ensuremath,\expandafter}
% \DoNotIndex{\hspace,\fi,\rule,\ifcase,\ifx,\in,\InputIfFileExists,\leq,\let,\mathpalette}
% \DoNotIndex{\NeedsTeXFormat,\ldots,\ldotp,\newcommand,\newcounter,\or}
% \DoNotIndex{\PackageInfo,\PackageWarning,\parm,\ProcessOptions,\protected@edef}
% \DoNotIndex{\providecommand,\ProvidesPackage,\relax,\renewcommand,\RequirePackage}
% \DoNotIndex{\setcounter,\setkeys,\rlap,\setminus,\widthof,\mathrm}
%
%\section{Usage}
%\DescribeEnv{restatable}
%Only one environment is provided: \verb|restatable|, which takes one
%optional and two mandatory arguments. The first mandatory argument is the
%type of the theorem, i.e. if you want |\begin{lemma}| to be called on
%the inside, give |lemma|. The second argument is the name of the macro
%that the text should be stored in, for example \verb|mylemma|. Be careful
%not to specify existing command names! The optional argument will become the
%optional argument to your theorem command. Consider the following example:
%\begin{verbatim}
%  \documentclass{article}
%  \usepackage{amsmath, amsthm, thm-restate}
%  \newtheorem{lemma}{Lemma}
%  \begin{document}
%    \begin{restatable}[Zorn]{lemma}{zornlemma}\label{thm:zorn}
%      If every chain in $X$ is upper-bounded, 
%      $X$ has a maximal element.
%
%      It's true, you know!
%    \end{restatable}
%    \begin{lemma}
%      This is some other lemma of no import.
%    \end{lemma}
%    And now, here's Mr. Zorn again: \zornlemma*
%  \end{document}
%\end{verbatim}
%which yields
%    \begin{restatable}[Zorn]{lemma}{zornlemma}\label{thm:zorn}
%      If every chain in $X$ is upper-bounded, $X$ has a maximal element.
%
%      It's true, you know!
%    \end{restatable}
%    \begin{lemma}
%      This is some other lemma of no import.
%    \end{lemma}
%    Actually, we have set a label in the environment, so we know that
%    it's Lemma~\ref{thm:zorn} on page~\ref{thm:zorn}.
%    And now, here's Mr. Zorn again: \zornlemma*
%    Since we prevent the label from being set again, we find that
%    it's still Lemma~\ref{thm:zorn} on page~\ref{thm:zorn}, even though
%    it occurs later also. 
%
% \DescribeEnv{restatable*}
% As you can see, we use the starred form |\mylemma*|. As in many cases in
% \LaTeX, the star means ``don't give a number'', since we want to retain
% the original number. There is also a starred variant of the |restatable|
% environment, where the first call doesn't determine the number, but a
% later call to |\mylemma| without star would. Since the number is carried
% around using \LaTeX' |\label| machanism, you'll need a rerun for things to
% settle.
%
% \subsection{Restrictions}
% The only counter that is saved is the one for the theorem number. So,
% putting floats inside a restatable is not advised. You cannot nest
% restatables either. You \emph{can} use the |\restatable|\dots|\endrestatable|
% version, but everything up to the next matching |\end{...}| is scooped up.
% I've also probably missed many border cases.
%
%
%\StopEventually{}
%\section{Implementation}
%    \begin{macrocode}
\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{thm-restate}[2008/03/09 v0.1beta2 thm-restate (ulmi)]

\let\@xa\expandafter
\let\@nx\noexpand
\@ifundefined{c@thmt@dummyctr}{%
  \newcounter{thmt@dummyctr}%
  }{}
\gdef\theHthmt@dummyctr{dummy.\arabic{thmt@dummyctr}}%
\gdef\thethmt@dummyctr{}%
\newtoks\thmt@toks
\long\def\thmt@collect@body#1#2\end#3{%
  \@xa\thmt@toks\@xa{\the\thmt@toks #2}%
  \def\thmttmpa{#3}%\def\thmttmpb{restatable}%
  \ifx\thmttmpa\@currenvir%thmttmpb
    \@xa\@firstoftwo% this is the end of the environment.
  \else
    \@xa\@secondoftwo% go on collecting
  \fi{%
    \@xa#1\@xa{\the\thmt@toks}%
  }{%
    \@xa\thmt@toks\@xa{\the\thmt@toks\end{#3}}%
    \thmt@collect@body{#1}%
  }%
}

\newif\ifthmt@thisistheone
\newenvironment{thmt@restatable}[3][]{%
  \long\def\thmrst@store##1{%
    \@xa\gdef\csname #3\endcsname{%
      \@ifstar{%
        \thmt@thisistheonefalse\csname thmt@stored@#3\endcsname
      }{%
        \thmt@thisistheonetrue\csname thmt@stored@#3\endcsname
      }%
    }%
    \@xa\long\@xa\gdef\csname thmt@stored@#3\@xa\endcsname\@xa{%
      \begingroup
      \ifthmt@thisistheone\else
        \@xa\protected@edef\csname the#2\endcsname{%
          \ifx\@refstar\@undefined\@xa\ref\else\@xa\@refstar\fi{thmt@@#3}}%
        \@xa\let\csname c@#2\endcsname=\c@thmt@dummyctr
        \@xa\let\csname theH#2\endcsname=\theHthmt@dummyctr
        \let\label=\@gobble
      \fi
      %\def\@currenvir{#2}%
      \csname #2\@xa\endcsname\ifx\@nx#1\@nx\else[#1]\fi
      \ifthmt@thisistheone
        \label{thmt@@#3}%
      \fi
      ##1
      \csname end#2\endcsname
      \endgroup
    }%
    \csname #3\@xa\endcsname\ifthmt@thisistheone\else*\fi
    \@xa\end\@xa{\@currenvir}
  }%
  \thmt@collect@body\thmrst@store
}{%
  %% now empty, just used as a marker.
}
\newenvironment{restatable}{%
  \thmt@thisistheonetrue\thmt@restatable
}{%
  \endthmt@restatable
}
\newenvironment{restatable*}{%
  \thmt@thisistheonefalse\thmt@restatable
}{%
  \endthmt@restatable
}
%    \end{macrocode}
%\iffalse
%</restate>
%\fi