% \iffalse
%% Source File: textcase.dtx
%% Copyright 1997 1998 2019 2022 2023 David Carlisle
%%
%% This file may be distributed under the terms of the LPPL.
%% See 00readme.txt for details.
%
%<*dtx>
          \ProvidesFile{textcase.dtx}
%</dtx>
%<package>\NeedsTeXFormat{LaTeX2e}
%<package>\ProvidesPackage{textcase}
%<driver> \ProvidesFile{textcase.drv}
% \fi
%         \ProvidesFile{textcase.dtx}
       [2023/07/27 v1.04 Text only upper/lower case changing (DPC)]
%
% \iffalse
%<*driver>
\documentclass{ltxdoc}
\usepackage{textcase}
\begin{document}
\DocInput{textcase.dtx}
\end{document}
%</driver>
% \fi
%
% \GetFileInfo{textcase.dtx}
%
% \changes{v0.01}{1997/09/28}
%    {Posted to c.t.t}
% \changes{v0.02}{1997/09/28}
%    {Support \cs{ensuremath}}
% \changes{v0.03}{1997/12/12}
%    {Donald Arseneau: support \cs{ref} \cs{cite} \cs{label}}
% \changes{v0.04}{1997/12/14}
%    {Convert to dtx form, add \cs{NoCaseChange}}
% \changes{v0.04}{1997/12/14}
%    {Support (most uses of) optional argument of \cs{cite}}
% \changes{v0.05}{1997/12/16}
%    {More comments from Donald,
%     perhaps I should just give him this package for Christmas}
% \changes{v0.06}{1998/11/12}
%    {overload option}
% \changes{v0.07}{2004/10/07}
%    {missing percent added}
%
%
% \title{The \textsf{textcase} package\thanks{This file
%        has version number \fileversion, last
%        revised \filedate.}}
% \author{David Carlisle\thanks{%^^A
%   Reorganisation to suppport skipping a wider class of
%   things than just math done by Donald Arseneau}}
%
% \date{\filedate}
%
% \maketitle
%
% \section{Introduction}\label{intro}
%
% \subsection*{This package is obsolete with the June 2022 \LaTeX\ release.}
% \begin{sloppypar}
%   With new formats |\MakeUppercase| supports the extensions provided
%   here, with improved support for UTF-8 input. So now the package
%   just defines |\MakeTextUppercase| and |\MakeTextLowercase| as
%   aliases for the standard |\MakeUppercase| and
%   |\MakeLowercase|\footnote{Since v1.04, not quite alises, one
%   grouping level is dropped for compatibility, required by
%   \textsf{amsart}.}.
% \end{sloppypar}
%
%
% \subsection*{Old Introduction}
% 
% |\MakeTextUppercase| and |\MakeTextLowercase| are versions of the
% standard |\MakeUppercase| and |\MakeLowercase| that do not change
% the case of any math sections in their arguments.
%\begin{verbatim}
% \MakeTextUppercase{abc\ae\ \( a = b \)  and $\alpha \neq a$ 
%   or even \ensuremath{x=y} and $\ensuremath{x=y}$}
%\end{verbatim}
% Should produce:
% \begin{quotation}
%  ABC\AE\ \( a = b \)  AND $\alpha \neq a$ 
%   OR EVEN \ensuremath{x=y} AND $\ensuremath{x=y}$
% \end{quotation}
%
% Version 0.03 of this package incorporates some changes suggested by
% Donald Arseneau so that as well as math mode, the arguments of
% |\cite|, |\label| and |\ref| are also prevented from being uppercased.
% So you can now go
%\begin{verbatim}
% \MakeTextUppercase{%
%    Text in section~\ref{intro}, about \cite[pp 2--4]{bbb}}
%\end{verbatim}
% which produces
% \begin{quotation}
% \MakeTextUppercase{%
%    Text in section~\ref{intro}, about \cite[pp 2--4]{bbb}}
% \end{quotation}
% If, instead, the standard |\MakeUppercase| were used here, the keys
% `into' and `bbb' would be uppercased and generate errors about
% undefined references to INTRO and BBB.
%
% Sometimes there may be a special section of text that should not be
% uppercased. This can be marked with |\NoCaseChange|, as follows.
%\begin{verbatim}
% \MakeTextUppercase{%
%    Text \NoCaseChange{More Text} yet more text}
%\end{verbatim}
% which produces
% \begin{quotation}
% \MakeTextUppercase{%
%    Text \NoCaseChange{More Text} yet more text}
% \end{quotation}
%
% |\NoCaseChange| has other uses. If for some reason you need a
% tabular environment within an uppercased section, then you need
% to ensure that the name `tabular' and the preamble (eg `ll')
% does not get uppercased:
%\begin{verbatim}
% \MakeTextUppercase{%
%    Text \NoCaseChange{\begin{tabular}{ll}}%
%                        table&stuff\\goes&here
%         \NoCaseChange{\end{tabular}}
%    More text}
%\end{verbatim}
% which produces
% \begin{quotation}
% \MakeTextUppercase{%
%    Text \NoCaseChange{\begin{tabular}{ll}}%^^A
%                        table&stuff\\goes&here
%         \NoCaseChange{\end{tabular}}
%    More text}
% \end{quotation}
%
% \section{Features and Foibles}
%
% \subsection{Nested text}
% The commands defined here only skip math sections and |\ref| arguments
% if they are not `hidden' inside a |{ }| brace group. All text inside
% such a group will be made uppercase just as with the standard
% |\MakeUppercase|.
%\begin{verbatim}
% \MakeTextUppercase{a b {c $d$} $e$}
%\end{verbatim}
% produces
% \begin{quotation}
%  \MakeTextUppercase{a b {c $d$} $e$}
% \end{quotation}
% Of course, this restriction does not apply to the arguments of the 
% supported commands |\ensuremath|, |\label|, |\ref|, and |\cite|.
%
% If you cannot arrange for your
% mathematics to be at the outer level of brace grouping, you should
% use the following basic technique (which works even with the standard
% |\MakeUppercase| command). Define a new command that expands to your
% math expression, and then use that command, with |\protect|, in the
% text to be uppercased. Note that if the text being uppercased is in a
% section title or other moving argument you may need to make the
% definition in the document preamble, rather than just before the
% section command, so that the command is defined when the table of
% contents file is read.
%\begin{verbatim}
% \MakeTextUppercase{%
%        Text \fbox{$a=b$ and $x=y$}}%
%
% \newcommand{\mathexprone}{$a=b$}
% \newcommand{\mathexprtwo}{$x=y$}
% \MakeTextUppercase{%
%        Text \fbox{\protect\mathexprone\ and \protect\mathexprtwo}}%
%\end{verbatim}
% which produces
% \begin{quotation}
% \MakeTextUppercase{%
%        Text \fbox{$a=b$ and $x=y$}}%
%
% \newcommand{\mathexprone}{$a=b$}
% \newcommand{\mathexprtwo}{$x=y$}
% \MakeTextUppercase{%
%        Text \fbox{\protect\mathexprone\ and \protect\mathexprtwo}}%
% \end{quotation}
%
% \subsection{Citations}
% As documented above, |\cite| and |\ref| commands are not uppercased by
% |\MakeTextUppercase|. If you are using a non-numeric citation scheme
% you may want the replacement text for |\cite| to be uppercased.
%
% It is difficult to arrange that |\MakeTextUppercase| uppercases such
% text, not least because this would lead to interaction with the many
% bibliography packages which redefine |\cite| one way or another. One
% possibility to achieve this is to use Donald Arseneau's cite package
% and to locally redefine |\citeform| to add |\MakeUppercase| around
% the final text string produced by |\cite|.
%\begin{verbatim}
% \MakeTextUppercase{%
%        Text \cite{bbb} and \cite{ccc}}
%
% {\renewcommand\citeform{\MakeUppercase}\MakeTextUppercase{%
%        Text \cite{bbb} and \cite{ccc}}}
%\end{verbatim}
% which produces\footnote{This is faked, so this document does not
%  rely on \texttt{cite.sty} being installed}
% \begin{quotation}
%  TEXT [1] AND [David Carlisle 1997]
%
%  TEXT [1] AND [DAVID CARLISLE 1997]
% \end{quotation}
%
% \subsection{overload Option}
% By default the package only defines new commands, |\MakeTextUppercase|
% and |\MakeTextlowercase| as described above. You may wish to redefine
% the standard |\MakeUppercase| and |\MakeLowercase| commands to be
% the same as these new commands. So that for example headings in the
% book class have this new feature without any further redefinition.
% You may use the package option |[overload]| in which case these
% new definitions will be overloaded on to the existing command names.
%
% \begin{thebibliography}{9}
%
% \bibitem{bbb} Something numeric
% \bibitem[David Carlisle 1997]{ccc} Something textual
% \end{thebibliography}
%
% \StopEventually{}
%
% \section{Implementation}
%
%    \begin{macrocode}
%<*package>
%    \end{macrocode}
%
% In current \LaTeX\ just define legacy names.
%    \begin{macrocode}
\ifx\AddToNoCaseChangeList\@undefined\else
  \DeclareOption{overload}{}
  \ProcessOptions
  \PackageInfo{textcase}{Defining Legacy names}
%    \end{macrocode}
% \changes{v1.04}{2023/07/27}
%    {define without outer group}
%    \begin{macrocode}
\ExplSyntaxOn
\cs_set_protected:Npn \reserved@a #1
 {
  \cs_generate_variant:cn { text_ \str_lowercase:n {#1} case:nn } { V }
  \ExpandArgs { cnx } \NewExpandableDocumentCommand
    { MakeText#1case }
    { O{} +m }
    { \exp_not:c { MakeText#1case \c_space_tl \c_space_tl \c_space_tl }
                           [####1] {####2} }
  }
\reserved@a { Upper }
\reserved@a { Lower }
\cs_new_protected:cpn {
   MakeTextLowercase \c_space_tl \c_space_tl \c_space_tl } [#1] #2
  {%{
    \let \OE \oe
    \@@text@case@aux { lower } {#1} {#2}
  }%}
\cs_new_protected:cpn {
   MakeTextUppercase \c_space_tl \c_space_tl \c_space_tl } [#1] #2
  {%{
    \let \oe \OE
    \@@text@case@aux { upper } {#1} {#2}
  }%}
\ExplSyntaxOff
%    \end{macrocode}
%
%    \begin{macrocode}
  \expandafter\endinput
\fi
%    \end{macrocode}
%
% \begin{macro}{\@uclcnotmath}
% This is the main macro of this package. It is basically
% a copy of |\MakeUppercase| and |\MakeLowercase|
% from the \LaTeX\ kernel, modified slightly so that they
% can share code (that modification could be done to the
% standard versions as well) and then further changed to
% skip certain features like math mode and |\label| arguments.
%
% The arguments are:\\
% |#1|: Extra commands to apply for case changing.
%       Used to locally redefine |\i| and |\j| for uppercasing.\\
% |#2|: Either |##1##2| or |##2##1| to control the order
%       in which |\let| is applied to the pairs of control
%       sequences in |\@uclclist|.\\
% |#3|:  |\uppercase| or |\lowercase|.\\
% |#4|: The text to be upper (or lower) cased.
%    \begin{macrocode}
\def\@uclcnotmath#1#2#3#4{\begingroup
%    \end{macrocode}
% Run extra commands (currently just to redefine |\i| and |\j|).
%    \begin{macrocode}
      #1%
%    \end{macrocode}
%
% Locally set |\( \)| to be just |$ $|, so that the math skipping
% code can be simplified, just to look for |$|.
%    \begin{macrocode}
      \def\({$}\let\)\(%
%    \end{macrocode}
%
% \changes{v1.00}{2019/09/14}
%    {UTF-8 support for 2019 LaTeX format}
% Allow UTF-8 characters to expand in the |\protected@edef| so that
% they become for example  |\IeC{\'{e}}| and uppercase correctly.
% \changes{v1.01}{2022/02/14}
%    {UTF-8 support for 2022 LaTeX format (unreleased)}
% \changes{v1.02}{2022/06/12}
%    {Obsolete this package in newer formats}
% \changes{v1.02s}{2022/067/10}
%    {Adjust test for newer formats}
% Allow UTF-8 characters are e-\TeX\ |\protected| in newer \LaTeX\ formats.
% 
%    \begin{macrocode}
      \let\UTF@two@octets@noexpand\@empty
      \let\UTF@three@octets@noexpand\@empty
      \let\UTF@four@octets@noexpand\@empty
%    \end{macrocode}
%
% Set up the `non-math' things that also have to be skipped.
%    \begin{macrocode}
      \def\NoCaseChange##1{\noexpand\NoCaseChange{\noexpand##1}}%
      \@nonchangecase\label
      \@nonchangecase\ref
      \@nonchangecase\ensuremath
%    \end{macrocode}
%
% |\cite| a bit trickier, as we want to uppercase any optional argument.
% This will fail if the optional argument contains a brace group, but
% should catch most cases.
%
% |text \cite[page 1]{foo} more text| ends up as
%\begin{verbatim}
% \uppercase{text \toks@{\cite[page1]}%
% \the\toks@{foo}%
% \uppercase{ more text}
%\end{verbatim}
%    \begin{macrocode}
      \def\cite##1##{\toks@{\noexpand\cite##1}\@citex}%
      \def\@citex##1{\NoCaseChange{\the\toks@{##1}}}%
%    \end{macrocode}
% (|\@citex| is a scratch macro here, not a redefinition of the existing
% |\@citex|.)
%
% The following is essentially taken from |\MakeUppercase|.
% Recursively execute |\reserved@a| to |\let| the pairs in |\@uclclist|.
% The strange construction with |\@gobble| at the end just gobbles the
% final recursive call.
%
% Incidentally, packages should not use the |\reserved@|\ldots\ scratch
% macros, which are `reserved' for use within the \LaTeX\ kernel, but
% (a) this code is essentially a copy from the kernel, and 
% (b) I'm allowed to break the rules, so there.
%    \begin{macrocode}
      \def\reserved@a##1##2{\let#2\reserved@a}%
      \expandafter\reserved@a\@uclclist\reserved@b{\reserved@b\@gobble}%
%    \end{macrocode}
%
% Expand everything first so that the `skipping' code can see what to
% skip and so that tokens are revealed to |\uppercase|.
% This makes the argument `moving'.
% The |$\valign$| is just a fake math expression used to terminate
% the parsing done by |\@skipmath|.
%    \begin{macrocode}
      \protected@edef\reserved@a{\endgroup
          \noexpand\@skipmath#3#4$\valign$}%
%    \end{macrocode}
%
%    \begin{macrocode}
      \reserved@a}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@nonchangecase}
%    \begin{macrocode}
\def\@nonchangecase#1{\def#1##1{\NoCaseChange{#1{##1}}}}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\NoCaseChange}
% For hiding arbitrary text from |\uppercase|. This innocuous
% definition is used for any occurrence of |\NoCaseChange|
% in text that is not passed to |\MakeTextUppercase|. For example a 
% section heading may be uppercased, but the toc entry may not.
% It is also used for nested definitions of |\cite| etc, where the 
% |\NoCaseChange| is inserted by expansion, but not removed as it is
% hidden by the brace group.
%    \begin{macrocode}
\let\NoCaseChange\@firstofone
%    \end{macrocode}
% \end{macro}
%
%\begin{macro}{\@skipmath}
% |#1|: operation |\uppercase| / |\lowercase|\\
% |#2|: text up to first (next) |$|\\
% |#3|: first math mode material (or |\valign| sentinel)
%    \begin{macrocode}
\def\@skipmath#1#2$#3${%
  \@skip@nonchangecase#1#2\NoCaseChange\valign
  \ifx\valign#3%
  \else
    $#3$%
    \expandafter\@skipmath\expandafter#1%
  \fi}
%    \end{macrocode}
% \end{macro}
%
%\begin{macro}{\@skip@nonchangecase}
% |#1|: |\uppercase| or |\lowercase|\\
% |#2|: Text up to the first command (such as |\cite|) made `safe'.
%       or the first use of |\NoCaseChange|.
%    \begin{macrocode}
\def\@skip@nonchangecase#1#2\NoCaseChange#3{%
  #1{#2}%
  \ifx\valign#3%
  \else
    #3%
    \expandafter\@skip@nonchangecase\expandafter#1%
  \fi}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\MakeTextUppercase}
% \changes{v0.06}{1998/11/12}
%    {Add edef to make behaviour more like \cs{MakeUppercase}}
% Put it all together. Arrange for \i\ and \j\ to uppercase, and
% to read the pairs in the ucase list `forwards'.
%    \begin{macrocode}
\DeclareRobustCommand\MakeTextUppercase{%
  \@uclcnotmath{\def\i{I}\def\j{J}}{##1##2}\uppercase}
%    \end{macrocode}
%
%    \begin{macrocode}
\protected@edef\MakeTextUppercase#1{\MakeTextUppercase{#1}}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\MakeTextLowercase}
% \changes{v0.06}{1998/11/12}
%    {Add edef to make behaviour more like \cs{MakeLowercase}}
% probably will never be used, but it is easy to implement.
% Use |\lowercase| and read the pairs in the uppercase list `backwards'.
%    \begin{macrocode}
\DeclareRobustCommand\MakeTextLowercase{%
  \@uclcnotmath{}{##2##1}\lowercase}
%    \end{macrocode}
%
%    \begin{macrocode}
\protected@edef\MakeTextLowercase#1{\MakeTextLowercase{#1}}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\MakeUppercase}
% \begin{macro}{\MakeLowercase}
% \changes{v0.06}{1998/11/12}
%    {Option to overload added.  latex/2906}
%    \begin{macrocode}
\DeclareOption{overload}{%
  \expandafter\let\csname MakeUppercase \expandafter\endcsname
                  \csname MakeTextUppercase \endcsname
  \expandafter\let\csname MakeLowercase \expandafter\endcsname
                  \csname MakeTextLowercase \endcsname}
%    \end{macrocode}
%
%    \begin{macrocode}
\ProcessOptions
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
%    \begin{macrocode}
%</package>
%    \end{macrocode}
%
% \Finale
%