refstate.dtx

% \iffalse meta-comment
%
%% File: refstate.dtx
%% Copyright (C) 2021--2024 by Maximilian Teegen
%%
%% This file may be distributed and/or modified under the
%% conditions of the LaTeX Project Public License, either
%% version 1.3c of this license or (at your option) any later
%% version. The latest version of this license is in:
%%
%% http://www.latex-project.org/lppl.txt
%%
%% and version 1.3 or later is part of all distributions of
%% LaTeX version 2005/12/01 or later.
%
%<*batch>
%<*gobble>
\ifx\jobname\relax\let\documentclass\undefined\fi
\ifx\documentclass\undefined
\csname fi\endcsname
%</gobble>
\input l3docstrip.tex
\keepsilent
\preamble
\endpreamble
\generate{\file{refstate.sty}{\from{refstate.dtx}{package}}}
\endbatchfile
%</batch>
%<*gobble>
\fi
\expandafter\ifx\csname @currname\endcsname\empty
\csname fi\endcsname
%</gobble>
% \fi
%
%<*driver>
\ProvidesFile{refstate.dtx}
%</driver>
%<package>\NeedsTeXFormat{LaTeX2e}[1999/12/01]
%<package>\ProvidesPackage{refstate}
%<*package>
    [2024/10/10 v0.2 ]
%</package>
%
%<*driver>
\documentclass{l3doc}
\usepackage{lmodern}
\usepackage{refstate}
\usepackage{hyperref}
\EnableCrossrefs
\CodelineIndex
\RecordChanges

\theoremstyle{plain}
\newtheorem{THM}{Theorem}[section]

\begin{document}
  \DocInput{refstate.dtx}
  \PrintChanges
  \PrintIndex
\end{document}
%</driver>
% \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         \~}
%
%
% \changes{v0.2}{2024/10/10}{Converted to DTX file}
%
% \DoNotIndex{\newcommand,\newenvironment}
%
% \providecommand*{\url}{\texttt}
% \GetFileInfo{refstate.dtx}
% \title{The \pkg{refstate} package}
% \author{Maximilian Teegen}
% \date{\fileversion~from \filedate}
%
% \maketitle
% \begin{documentation}
% \section{Introduction}
%
% The \pkg{refstate} package provides a mechanism to pre-state and re-state theorems in a \LaTeX\ document.
% It relies on the implementation details of the \pkg{amsthm} package and \textbf{may break if those details change}.
%
% \section{Usage}
%
% To use the \pkg{refstate} package, include it in your document preamble with:
% \begin{verbatim}
% \usepackage{refstate}
% \end{verbatim}
% Declare your theorem environments like normal.
% \begin{verbatim}
% \theoremstyle{plain}
% \newtheorem{THM}{Theorem}[section]
% \end{verbatim}
%
% \begin{function}{store}
% You can then use the \env{store} environment to define a theorem like this.
%
% \begin{verbatim}
% \begin{store}{THM}[Blue sky theorem]\label{thmmain}
%     The sky is blue.
% \end{store}
% \end{verbatim}
% \hrule
% \begin{store}{THM}[Blue sky theorem]\label{thmmain}
%     The sky is blue.
% \end{store}
% \hrule
% \end{function}
%
% \begin{function}{\refstate}
% Elsewhere in the document (before or after), use the \tn{refstate} command to reference it.
%
% \begin{verbatim}
% \refstate{thmmain}
% \end{verbatim}
% \hrule
% \refstate{thmmain}
% \hrule
% \end{function}
%
% \end{documentation}
%
% \StopEventually{}
%
% \section{Implementation}
% \begin{implementation}
%
% \iffalse
%<*package>
% \fi
%
%    \begin{macrocode}
\ProvidesPackage{refstate}
\RequirePackage{amsthm,xparse}
\RequirePackage{marginnote}
\ExplSyntaxOn
%    \end{macrocode}
% Redefine \tn{newtheorem} to capture theorem styles and names and save them to macros.
%    \begin{macrocode}
\let\rfst@newtheorem@original=\newtheorem
\RenewDocumentCommand{\newtheorem}{s m o m o}{
  \tl_if_in:nnTF {#2} {phfthm@} {
    \tl_set:Nx \l_tmpa_tl
      {\tl_range:nnn{#2}{8}{-1}}
    \cs_if_exist:NTF \cmdKV@phfmkthm@thmstyle {
      \if\relax\detokenize\expandafter{\cmdKV@phfmkthm@thmstyle}\relax % ... why?
        \tl_const:cx {rfst@style@\tl_use:N\l_tmpa_tl} {\the\thm@style}
      \else
        \tl_const:cx {rfst@style@\tl_use:N\l_tmpa_tl} {\cmdKV@phfmkthm@thmstyle}
      \fi
    }{
      \tl_const:cx {rfst@style@\tl_use:N\l_tmpa_tl} {\the\thm@style}
    }
    \tl_const:cx {rfst@style@#2} {plain}
    \tl_const:cx {rfst@name@\tl_use:N\l_tmpa_tl}
      {#4}
  }{
    \tl_const:cx {rfst@style@#2} {\the\thm@style}
    \tl_const:cx {rfst@name@#2} {#4}
  }
  \IfBooleanTF{#1}{
    \IfValueTF{#3}{
      \IfValueTF{#5}{
        \rfst@newtheorem@original*{#2}[#3]{#4}[#5]
      }{
        \rfst@newtheorem@original*{#2}[#3]{#4}
      }
    }{
      \IfValueTF{#5}{
        \rfst@newtheorem@original*{#2}{#4}[#5]
      }{
        \rfst@newtheorem@original*{#2}{#4}
      }
    }
  }{
    \IfValueTF{#3}{
      \IfValueTF{#5}{
        \rfst@newtheorem@original{#2}[#3]{#4}[#5]
      }{
        \rfst@newtheorem@original{#2}[#3]{#4}
      }
    }{
      \IfValueTF{#5}{
        \rfst@newtheorem@original{#2}{#4}[#5]
      }{
        \rfst@newtheorem@original{#2}{#4}
      }
    }
  }
}
%    \end{macrocode}
% Define a theorem-environment lookalike command for the restated theorem.
% We gobble the \tn{label} command for the body so that there is no labels.
%  \begin{macrocode}
\NewExpandableDocumentCommand{\rfst@gobble@label}{o m}{}
\NewDocumentCommand{\rfst@faketheorem}{m m m m +m O{}}{
   % 1=Label 2=Style 3=Type 4=TypeName 5=Body 6=Head
   \begingroup
   \let\label\rfst@gobble@label
   % \let\index\@gobble \let\glossary\@gobble
   % Not all of these may be desirable...
   \ifhmode\unskip\unskip\par\fi
   \normalfont
   \trivlist
   \let\thmheadnl\relax
   \let\thm@swap\@gobble
   \thm@notefont{\fontseries\mddefault\upshape}%
   \thm@headpunct{.}% add period after heading
   \thm@headsep 5\p@ plus\p@ minus\p@\relax
   \thm@space@setup
   \csname th@#2\endcsname
   \@topsep \thm@preskip         % used by thm head
   \@topsepadd \thm@postskip       % used by \@endparenv
   \@begintheorem{#4}{\ref{#1}}[#6]
   \marginnote{\textit{\footnotesize$\leadsto$\,p.\,\pageref*{#1}}}
   \ignorespaces
   #5
   \@endtheorem
   \endgroup
}
%    \end{macrocode}
% \begin{macro}{\refstate}
%  \begin{macrocode}
\newcommand{\refstate}[1]{%
  \ifcsname rfst@storedthm@#1\endcsname
    \@nameuse{rfst@storedthm@#1}
  \else
%    \end{macrocode}
% We need an other run of latex. Put a placeholder.
%  \begin{macrocode}
    \ifhmode\unskip\unskip\par\fi
    \thm@space@setup
    \vskip\thm@preskip
    \noindent
    \textbf{Restate}~\texttt{\detokenize{#1}}
    \par
    \vskip\thm@postskip
  \fi
}
%    \end{macrocode}
% \end{macro}
%
%  \begin{macrocode}
\NewExpandableDocumentCommand{\rfst@thm@detok}{o m m m}{
  \detokenize{{#2}{#3}{#4}}
}
\NewDocumentEnvironment{store}{ m o +b } {%
  \IfValueTF{#2}{\begin{#1}[#2]}{\begin{#1}} % Begin wrapped theorem
    \newtoks\rfst@labelval % Capture the first label.
    \let\rfst@oldlabel\label
    \newcommand{\rfst@label}[1]{\rfst@labelval{##1}\let\label\rfst@oldlabel\label{##1}}
    \let\label\rfst@label
    #3 % Display the actual theorem contents
%    \end{macrocode}
% Store all the info needed to refstate the theorem into the aux file
%  \begin{macrocode}
    \begingroup
      \let\@thm=\rfst@thm@detok
      \protected@write\@auxout{}{%
        \string\global\string\long\string\@namedef{rfst@storedthm@\the\rfst@labelval}{%
          \string\rfst@faketheorem%
          {\the\rfst@labelval}%
          {\tl_use:c{rfst@style@#1}}{#1}{\tl_use:c{rfst@name@#1}}
          {\detokenize{#3}}%
          \IfValueT{#2}{[#2]}%
        }
      }
    \endgroup
  \end{#1} % End wrapped theorem
} {}
%    \end{macrocode}
% \end{implementation}

%
% \iffalse
%</package>
% \fi
%
% \Finale
\endinput