% \iffalse meta-comment
%
% File: expkv-opt.dtx Copyright (C) 2020-2023 Jonathan P. Spratte
%
% This work  may be  distributed and/or  modified under  the conditions  of the
% LaTeX Project Public License (LPPL),  either version 1.3c  of this license or
% (at your option) any later version.  The latest version of this license is in
% the file:
%
%   http://www.latex-project.org/lppl.txt
%
% ------------------------------------------------------------------------------
%
%<*driver>^^A>>=
\def\nameofplainTeX{plain}
\ifx\fmtname\nameofplainTeX\else
  \expandafter\begingroup
\fi
\input l3docstrip.tex
\askforoverwritefalse
\preamble

--------------------------------------------------------------
expkv-opt -- parse class and package options with expkv
E-mail: jspratte@yahoo.de
Released under the LaTeX Project Public License v1.3c or later
See http://www.latex-project.org/lppl.txt
--------------------------------------------------------------

Copyright (C) 2020-2023 Jonathan P. Spratte

This  work may be  distributed and/or  modified under  the conditions  of the
LaTeX Project Public License (LPPL),  either version 1.3c  of this license or
(at your option) any later version.  The latest version of this license is in
the file:

  http://www.latex-project.org/lppl.txt

This work is "maintained" (as per LPPL maintenance status) by
  Jonathan P. Spratte.

This work consists of the file  expkv-opt.dtx
and the derived files           expkv-opt.pdf
                                expkv-opt.sty
and the file                    expkv-opt-2020-10-10.dtx
and the derived file            expkv-opt-2020-10-10.sty

\endpreamble
% stop docstrip adding \endinput
\postamble
\endpostamble
\generate{\file{expkv-opt-2020-10-10.sty}{\from{expkv-opt-2020-10-10.dtx}{pkg}}}
\ifx\fmtname\nameofplainTeX
  \expandafter\endbatchfile
\else
  \expandafter\endgroup\expandafter\stop
\fi
%
\IfFileExists{expkv-opt.sty}{\RequirePackage{expkv-opt}}{}
\ProvidesFile{expkv-opt.dtx}
  [\csname ekvoDate\endcsname\ parse class and package options with expkv]
\PassOptionsToPackage{full}{textcomp}
\documentclass{l3doc}
\RequirePackage[oldstylenums,nott]{kpfonts}
\input{glyphtounicode}
\pdfgentounicode=1
\RequirePackage{listings}
\RequirePackage{booktabs}
\RequirePackage{array}
\RequirePackage{collcell}
\RequirePackage{siunitx}
\RequirePackage{xcolor}
\RequirePackage{caption}
\RequirePackage{microtype}
\RequirePackage{accsupp}
\lstset
  {
    ,flexiblecolumns=false
    ,basewidth=.53em
    ,gobble=2
    ,basicstyle=\fontfamily{jkp}\itshape
    ,morekeywords=^^A
      {^^A
        \ekvoProcessLocalOptions,
        \ekvoProcessGlobalOptions,
        \ekvoProcessUnusedGlobalOptions,
        \ekvoProcessOptionsList,
        \ekvoUseUnknownHandlers
      }
    ,morecomment=[l]\%
    ,commentstyle=\color[gray]{0.4}
    ,literate={\{}{{\CodeSymbol\{}}{1}
              {\}}{{\CodeSymbol\}}}{1}
    ^^A,literate=*{<key>}{\key}{4}{<set>}{\set}{4}
  }
\newcommand*\CodeSymbol[1]{\textbf{#1}}
\RequirePackage{randtext}
\let\metaORIG\meta
\protected\def\meta #1{\texttt{\metaORIG{#1}}}
\renewcommand*\thefootnote{\fnsymbol{footnote}}
\definecolor{expkvred}{HTML}{9F393D}
\colorlet{expkvgrey}{black!75}
\makeatletter
\newcommand*\expkv
  {^^A
    \texorpdfstring
      {^^A
        \mbox
          {^^A
            \BeginAccSupp{ActualText=expkv}^^A
            \href{https://github.com/Skillmon/tex_expkv}
              {^^A
                \rmfamily
                \bfseries
                {\color{expkvgrey}e\kern-.05em x\kern-.05em}^^A
                \lower.493ex
                  \hbox{{\color{expkvgrey}P}\kern-.1em{\color{expkvred}k}}^^A
                \kern-.18em{\color{expkvred}v}^^A
              }^^A
            \EndAccSupp{}^^A
          }^^A
      }
      {expkv}^^A
  }
\newcommand*\expkvpkg[1]
  {^^A
    \texorpdfstring
      {^^A
        \mbox
          {^^A
            \BeginAccSupp{ActualText=expkv-#1}^^A
            \href{https://github.com/Skillmon/tex_expkv-#1}
              {^^A
                \rmfamily
                \bfseries
                {\color{expkvgrey}e\kern-.05em x\kern-.05em}^^A
                \lower.493ex
                  \hbox{{\color{expkvgrey}P}\kern-.1em{\color{expkvred}k}}^^A
                \kern-.18em{\color{expkvred}v}^^A
                {\color{expkvgrey}^^A
                  \kern.05em\rule[-.1ex]{.08em}{1.2ex}\kern.05em\textsc{#1}^^A
                }^^A
              }^^A
            \EndAccSupp{}^^A
          }^^A
      }
      {expkv-#1}^^A
  }
\newcommand*\expkvd{\expkvpkg{def}}
\newcommand*\expkvc{\expkvpkg{cs}}
\newcommand*\expkvo{\expkvpkg{opt}}
\newcommand\kv{\meta{key}=\meta{value}}
\newcommand\key{\meta{key}}
\newcommand\val{\meta{value}}
\newcommand\set{\meta{set}}
\newcommand\enfprot{\textcolor{black}{protected}}
\newcommand\allprot{\textcolor{gray}{protected}}
\newcommand\notprot{\textcolor{red!80!black}{protected}}
\newcommand\enflong{\textcolor{black}{long}}
\newcommand\alllong{\textcolor{gray}{long}}
\newcommand\notlong{\textcolor{red!80!black}{long}}
\newcommand\prefixes[2]
  {^^A
    \hfill
    \ifcase\numexpr#1\relax\or
      \enfprot\or
      \allprot\or
      \notprot\fi\space
    \ifcase\numexpr#2\relax\or
      \enflong\or
      \alllong\or
      \notlong\fi
  }
\hypersetup{linkcolor=red!80!black,urlcolor=purple!80!black}
\DoNotIndex{\def,\edef,\,,\=,\begingroup,\catcode,\chardef,\csname,\endcsname}
\DoNotIndex{\endgroup,\endinput,\errmessage,\expandafter,\input,\let,\long}
\DoNotIndex{\protected,\ProvidesFile,\ProvidesPackage,\relax,\space}
\DoNotIndex{\@,\unexpanded,\string,\expanded,\dimexpr,\global,\glueexpr,\hbox}
\DoNotIndex{\numexpr,\RequirePackage,\setbox,\the,\unless,\xdef,\@firstofone}
\DoNotIndex{\@firstoftwo,\@gobble,\@secondoftwo,\AtEndOfPackage,\newcommand}
\DoNotIndex{\PackageError,\@classoptionslist,\@clsextension,\@currext}
\DoNotIndex{\@currname,\@empty,\@gobbletwo,\@onlypreamble,\@unprocessedoptions}
\DoNotIndex{\@unusedoptionlist}
\DoNotIndex{\ifcsname}
\DoNotIndex{\ifx}
\DoNotIndex{\ifdefined}
\DoNotIndex{\iffalse}
\DoNotIndex{\iftrue}
\DoNotIndex{\else}
\DoNotIndex{\fi}
\@gobble\fi ^^A ignoring \ifx, \ifcsname, etc., but only one \fi
\@gobble\fi ^^A ignoring \ifx, \ifcsname, etc., but only one \fi
\@gobble\fi ^^A ignoring \ifx, \ifcsname, etc., but only one \fi
\@gobble\fi ^^A ignoring \ifx, \ifcsname, etc., but only one \fi
\@ifdefinable\gobbledocstriptag{\def\gobbledocstriptag#1>{}}
\makeatother
\begin{document}
  \title
    {^^A
      \texorpdfstring
        {^^A
          \huge\expkvo
          \\[\medskipamount]
          \Large parse class and package options with \expkv
        }{expkv-opt - parse class and package options with expkv}^^A
    }
  \date{\ekvoDate\space v\ekvoVersion}
  \author{Jonathan P. Spratte\thanks{\protect\randomize{jspratte@yahoo.de}}}
  \DocInput{expkv-opt.dtx}
\end{document}
%</driver>^^A=<<
% \fi
%
% \maketitle
% \renewcommand*\thefootnote{\arabic{footnote}}
%
% \begin{abstract}
% \noindent\parfillskip=0pt
% \expkvo\ provides option parsing for classes and packages in \LaTeXe\ based on
% \expkv. Global and local options are parsed individually by different
% commands. The stylised name is \expkvo\ but the files use \file{expkv-opt},
% this is due to CTAN-rules which don't allow \string| in package names since
% that is the pipe symbol in *nix shells.
% \end{abstract}
%
% \tableofcontents
%
% \begin{documentation}^^A>>=
%
% \section{Documentation}
%
% The \expkv\ family provides at its core a \kv\ parser and additionally
% packages, one to conveniently define new keys (\expkvd) and another to build
% expandable \kv\ taking control sequences (\expkvc). Still missing from the mix
% was a solution to parse \LaTeXe\ class and package options, a gap that's
% hereby filled with \expkvo.
%
% \expkvo\ shouldn't place any restrictions on the keys, but note that parts of
% \LaTeXe\ can break if the \kv\ list contains braces. This includes the global
% options list depending on which class you're using. Also keep in mind that
% every value provided should be save from an |\edef| expansion, as the space
% stripping code of \LaTeXe\ options (which is applied before \expkvo\ takes
% control) uses such an expansion.
%
% The package can be loaded with
% \begin{lstlisting}
% \usepackage{expkv-opt}
% \end{lstlisting}
% Unlike the other packages in the \expkv\ family, \expkvo\ is only provided as
% a \LaTeX\ package.
%
% Before reading this documentation you should read \expkv's documentation and
% might want to also read the documentation of \expkvd.
%
%
% \subsection{Macros}
%
% \expkvo's behaviour if it encounters a defined or an undefined \key\ depends
% on which list is being parsed and whether the current file is a class or not.
% Of course in every case a defined \key's callback will be invoked but an
% additional action might be executed. For this reason the rule set of every
% macro will be given below the short description which list it will parse. 
%
% During each of the processing macros the current list element (not separated
% in \key\ and \val\ but as a whole) is stored within the macro
% \cs{CurrentOption}.
%
% \begin{function}{\ekvoProcessLocalOptions}
%   \begin{syntax}
%     \cs{ekvoProcessLocalOptions}\marg{set}
%   \end{syntax}
%   This parses the options which are directly passed to the current class or
%   package for an \expkv\ \set.
% \end{function}
% \begin{description}
%   \item[Class:]
%     \begin{description}
%       \item[defined] \emph{nothing}
%       \item[undefined]
%         add the key to the list of unused global options (if the local option
%         list matches the option list of the main class)
%     \end{description}
%   \item[Package:]
%     \begin{description}
%       \item[defined] \emph{nothing}
%       \item[undefined] throw an error
%     \end{description}
% \end{description}
%
% \begin{function}{\ekvoProcessGlobalOptions}
%   \begin{syntax}
%     \cs{ekvoProcessGlobalOptions}\marg{set}
%   \end{syntax}
%   In \LaTeXe\ the options given to |\documentclass| are global options. This
%   macro processes the global options for an \expkv\ \set.
% \end{function}
% \begin{description}
%   \item[Class:]
%     \begin{description}
%       \item[defined] remove the option from the list of unused global options
%       \item[undefined] \emph{nothing}
%     \end{description}
%   \item[Package:]
%     \begin{description}
%       \item[defined] remove the option from the list of unused global options
%       \item[undefined] \emph{nothing}
%     \end{description}
% \end{description}
%
% \begin{function}{\ekvoProcessUnusedGlobalOptions}
%   \begin{syntax}
%     \cs{ekvoProcessUnusedGlobalOptions}\marg{set}
%   \end{syntax}
%   If you want to, instead of parsing all global options, you can parse only
%   those global options which weren't yet used by another package or class.
% \end{function}
% \begin{description}
%   \item[Class:]
%     \begin{description}
%       \item[defined] remove the option from the list of unused global options
%       \item[undefined] \emph{nothing}
%     \end{description}
%   \item[Package:]
%     \begin{description}
%       \item[defined] remove the option from the list of unused global options
%       \item[undefined] \emph{nothing}
%     \end{description}
% \end{description}
%
% \begin{function}{\ekvoProcessOptionsList}
%   \begin{syntax}
%     \cs{ekvoProcessOptionsList}\meta{list}\marg{set}
%   \end{syntax}
%   Process the \kv\ list stored in the macro \meta{list}.
% \end{function}
% \begin{description}
%   \item[Class:]
%     \begin{description}
%       \item[defined] \emph{nothing}
%       \item[undefined] \emph{nothing}
%     \end{description}
%   \item[Package:]
%     \begin{description}
%       \item[defined] \emph{nothing}
%       \item[undefined] \emph{nothing}
%     \end{description}
% \end{description}
%
% \begin{function}{\ekvoUseUnknownHandlers}
%   \begin{syntax}
%     \cs{ekvoUseUnknownHandlers}\meta{cs_1}\meta{cs_2}
%   \end{syntax}
%   With this macro you can change the action \expkvo\ executes if it encounters
%   an undefined \key\ for the next (and only the next) list processing macro.
%   The macro \meta{cs_1} will be called if an undefined \key\ without a \val\
%   is encountered and get one argument, being the \key. Analogous the macro
%   \meta{cs_2} will be called if an undefined \key\ with a \val\ was specified.
%   It will get two arguments, the first being the \key\ and the second the
%   \val.
% \end{function}
%
% \begin{function}{\ekvoVersion,\ekvoDate}
%   These two macros store the version and date of the package.
% \end{function}
%
%
% \subsection{Example}
%
% Let's say we want to create a package that changes the way footnotes are
% displayed in \LaTeX. For this it will essentially just redefine
% \cs[no-index]{thefootnote} and we'll call this package \pkg{ex-footnote}.
% First we report back which package we are:
% \begin{lstlisting}
% \ProvidesPackage{ex-footnote}[2020-02-02 v1 change footnotes]
% \end{lstlisting}
% Next we'll need to provide the options we want the package to have.
% \begin{lstlisting}
% \RequirePackage{color}
% \RequirePackage{expkv-opt} % also loads expkv
% \ekvdef{ex-footnote}{color}{\def\exfn@color{#1}}
% \ekvdef{ex-footnote}{format}{\def\exfn@format{#1}}
% \end{lstlisting}
% We can provide initial values just by defining the two macros storing the
% value.
% \begin{lstlisting}
% \newcommand*\exfn@color{}
% \newcommand*\exfn@format{arabic}
% \end{lstlisting}
% Next we need to process the options given to the package. The package should
% only obey options directly passed to it, so we're only using
% |\ekvoProcessLocalOptions|:
% \begin{lstlisting}
% \ekvoProcessLocalOptions{ex-footnote}
% \end{lstlisting}
% Now everything that's still missing is actually changing the way footnotes
% appear:
% \begin{lstlisting}
% \renewcommand*\thefootnote
%   {%
%     \ifx\exfn@color\@empty
%       \csname\exfn@format\endcsname{footnote}%
%     \else
%       \textcolor{\exfn@color}{\csname\exfn@format\endcsname{footnote}}%
%     \fi
%   }
% \end{lstlisting}
% \bigskip
%
% \noindent
% So the complete code of the package would look like this:
% \begin{lstlisting}
% \ProvidesPackage{ex-footnote}[2020-02-02 v1 change footnotes]
%
% \RequirePackage{color}
% \RequirePackage{expkv-opt} % also loads expkv
%
% \ekvdef{ex-footnote}{color}{\def\exfn@color{#1}}
% \ekvdef{ex-footnote}{format}{\def\exfn@format{#1}}
% \newcommand*\exfn@color{}
% \newcommand*\exfn@format{arabic}
%
% \ekvoProcessLocalOptions{ex-footnote}
%
% \renewcommand*\thefootnote
%   {%
%     \ifx\exfn@color\@empty
%       \csname\exfn@format\endcsname{footnote}%
%     \else
%       \textcolor{\exfn@color}{\csname\exfn@format\endcsname{footnote}}%
%     \fi
%   }
% \end{lstlisting}
% \bigskip
%
% \noindent
% And it could be used with one of the following lines:
% \begin{lstlisting}
% \usepackage{ex-footnote}
% \usepackage[format=fnsymbol]{ex-footnote}
% \usepackage[color=green]{ex-footnote}
% \usepackage[color=red,format=roman]{ex-footnote}
% \end{lstlisting}
%
%
% \subsection{Bugs}
%
% If you happen to find bugs, it'd be great if you let me know. Just write me an
% email (see the front page) or submit a bug report on GitHub:
% \url{https://github.com/Skillmon/tex_expkv-opt}
%
%
% \subsection{License}
%
% Copyright \textcopyright\ 2020\unless\ifnum\year=2020--\the\year\fi\
% Jonathan P. Spratte
%
% \medskip\noindent
% This work may be distributed and/or modified under the conditions of the
% \LaTeX\ Project Public License (LPPL), either version 1.3c of this license or
% (at your option) any later version. The latest version of this license is in
% the file:
%
% \url{http://www.latex-project.org/lppl.txt}
%
% \noindent
% This work is ``maintained'' (as per LPPL maintenance status) by
%
% \mbox{Jonathan P. Spratte}.
%
% \end{documentation}^^A=<<
%
% \begin{implementation}^^A>>=
%
% \clearpage
%
%
% \section{Implementation}
%
% \gobbledocstriptag
%<*pkg>
% Start the package with the typical \LaTeX\ standards.
% 
% \begin{macro}{\ekvoVersion,\ekvoDate}
%   Store the packages version and date in two macros.
%    \begin{macrocode}
\newcommand*\ekvoVersion{0.1c}
\newcommand*\ekvoDate{2020-10-10}
%    \end{macrocode}
% \end{macro}
% And we report who we are and what we need.
%    \begin{macrocode}
\ProvidesPackage{expkv-opt}
  [%
    \ekvoDate\space v\ekvoVersion\space
    parse class and package options with expkv%
  ]
\RequirePackage{expkv}
%    \end{macrocode}
%
%
% \subsection{Loop}
%
% \begin{macro}[internal]
%   {\ekvo@CurrentOption@loop,\ekvo@CurrentOption@loop@,\ekvo@end@loop}
%   We'll need some loop which can iterate over a comma separated list. The loop
%   is very basic and only works for commas of category~12. First we insert the
%   delimiters for the actual loop. The |\ekv@set@other| is necessary to get a
%   functional |\ekvmorekv| in this loop.
%    \begin{macrocode}
\protected\long\def\ekvo@CurrentOption@loop#1#2%
  {%
    \ekvo@CurrentOption@loop@#2\ekv@set@other\ekv@mark#1,\ekv@stop,\ekvo@tail
  }
%    \end{macrocode}
%   The actual loop checks whether the final element has been read and if so
%   ends the loop. Else blank elements are ignored, |\CurrentOption| is set and
%   the macro which parses the list elements called. Then call the next
%   iteration.
%    \begin{macrocode}
\long\def\ekvo@CurrentOption@loop@#1\ekv@set@other#2,%
  {%
    \ekv@gobble@from@mark@to@stop#2\ekvo@end@loop\ekv@stop
    \ekv@ifblank{#2}%
      {}%
      {%
        \edef\CurrentOption{\unexpanded\expandafter{\ekv@gobble@mark#2}}%
        #1{#2}%
      }%
    \ekvo@CurrentOption@loop@#1\ekv@set@other\ekv@mark
  }
\long\def\ekvo@end@loop#1\ekvo@tail{}
%    \end{macrocode}
% \end{macro}
%
%
% \subsection{Tests}
%
% \begin{macro}[internal]{\ekvo@ifx@TF,\ekvo@ifx@F}
%   We'll need branching |\ifx| tests so that user input containing unbalanced
%   \TeX\ ifs doesn't break (at least not because of us, everything else is the
%   fault of \LaTeXe).
%    \begin{macrocode}
\def\ekvo@ifx@TF#1#2{\ifx#1#2\ekv@fi@firstoftwo\fi\@secondoftwo}
\def\ekvo@ifx@F#1#2{\ifx#1#2\ekv@fi@gobble\fi\@firstofone}
%    \end{macrocode}
% \end{macro}
% 
% \begin{macro}[internal]{\ekvo@do@with@set,\ekvo@name,\ekvo@setname}
%   This test checks whether the \set\ is defined.  If it is we store it in
%   |\ekvo@setname| and set |\ekvo@name| to a short cut to get the \key's
%   callback name. Next we execute the code in |#2|, if the \set\ isn't defined
%   |#2| is gobbled.
%    \begin{macrocode}
\protected\def\ekvo@do@with@set#1#2%
  {%
    \ekvifdefinedset{#1}%
      {%
        \expandafter
        \let\expandafter\ekvo@name\csname\ekv@undefined@set{#1}\endcsname
        \def\ekvo@setname{#1}%
        #2%
      }%
      {\ekvo@err@undefined@set{#1}}%
  }
%    \end{macrocode}
% \end{macro}
%
%
% \subsection{Key handlers}
%
% \expkvo\ uses handlers specifying what happens if a parsed \key\ is defined or
% undefined.
%
% \begin{macro}[internal]
%   {\ekvo@handle@undefined@k@pkg,\ekvo@handle@undefined@kv@pkg}
%   The case for undefined keys in a local list of a package is easy, just throw
%   appropriate errors.
%    \begin{macrocode}
\protected\long\def\ekvo@handle@undefined@k@pkg#1%
  {%
    \ekv@ifdefined{\ekvo@name{#1}}%
      {\ekvo@err@value@required{#1}}%
      {\ekvo@err@undefined@key{#1}}%
  }
\def\ekvo@handle@undefined@kv@pkg#1#2%
  {%
    \ekv@ifdefined{\ekvo@name{#1}N}%
      {\ekvo@err@value@forbidden{#1}}%
      {\ekvo@err@undefined@key{#1}}%
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[internal]
%   {
%     \ekvo@addto@unused@one,\ekvo@addto@unused@two,
%     \ekvo@rmfrom@unused@one,\ekvo@rmfrom@unused@two
%   }
%   These macros will add or remove the |\CurrentOption| to or from the list of
%   unused global options.
%    \begin{macrocode}
\long\def\ekvo@addto@unused@one#1{\ekvo@addto@list\@unusedoptionlist}
\long\def\ekvo@addto@unused@two#1#2{\ekvo@addto@list\@unusedoptionlist}
\long\def\ekvo@rmfrom@unused@one#1{\ekvo@rmfrom@list\@unusedoptionlist}
\long\def\ekvo@rmfrom@unused@two#1#2{\ekvo@rmfrom@list\@unusedoptionlist}
%    \end{macrocode}
% \end{macro}
% \begin{macro}[internal]
%   {
%     \ekvo@set@handlers@local,\ekvo@set@handlers@global,
%     \ekvo@set@handlers@unusedglobal,\ekvo@set@handlers@list
%   }
%   These macros are boring. They just set up the handlers to respect the rules
%   documented earlier.
%    \begin{macrocode}
\protected\def\ekvo@set@handlers@local
  {%
    \ekvo@if@need@handlers
      {%
        \ifx\@currext\@clsextension
          \ifx\@classoptionslist\relax
            \let\ekvo@handle@undefined@k\@gobble
            \let\ekvo@handle@undefined@kv\@gobbletwo
          \else
            \expandafter
            \ifx\csname opt@\@currname.\@currext\endcsname\@classoptionslist
              \let\ekvo@handle@undefined@k\ekvo@addto@unused@one
              \let\ekvo@handle@undefined@kv\ekvo@addto@unused@two
            \else
              \let\ekvo@handle@undefined@k\@gobble
              \let\ekvo@handle@undefined@kv\@gobbletwo
            \fi
          \fi
        \else
          \let\ekvo@handle@undefined@k\ekvo@handle@undefined@k@pkg
          \let\ekvo@handle@undefined@kv\ekvo@handle@undefined@kv@pkg
        \fi
      }%
  }
\protected\def\ekvo@set@handlers@global
  {%
    \unless\ifx\@unusedoptionlist\@empty
      \let\ekvo@handle@defined@k\ekvo@rmfrom@unused@one
      \let\ekvo@handle@defined@kv\ekvo@rmfrom@unused@two
    \fi
    \ekvo@if@need@handlers
      {%
        \let\ekvo@handle@undefined@k\@gobble
        \let\ekvo@handle@undefined@kv\@gobbletwo
      }%
  }
\protected\def\ekvo@set@handlers@unusedglobal
  {%
    \ekvo@if@need@handlers
      {%
        \let\ekvo@handle@undefined@k\ekvo@addto@unused@one
        \let\ekvo@handle@undefined@kv\ekvo@addto@unused@two
        \let\@unusedoptionlist\@empty
        \@gobbletwo
      }%
    \@firstofone
      {%
        \let\ekvo@handle@defined@k\ekvo@rmfrom@unused@one
        \let\ekvo@handle@defined@kv\ekvo@rmfrom@unused@two
      }%
  }
\protected\def\ekvo@set@handlers@list
  {%
    \ekvo@if@need@handlers
      {%
        \let\ekvo@handle@undefined@k\@gobble
        \let\ekvo@handle@undefined@kv\@gobbletwo
      }%
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[internal]{\ekvo@if@need@handlers,\ekvo@dont@need@handlers}
%   If the user specifies handlers this macro will be let to
%   |\ekvo@dont@need@handlers|, which will act like |\@gobble| and also let it
%   to |\@firstofone| afterwards.
%    \begin{macrocode}
\let\ekvo@if@need@handlers\@firstofone
\protected\long\def\ekvo@dont@need@handlers#1%
  {%
    \let\ekvo@if@need@handlers\@firstofone
  }%
%    \end{macrocode}
% \end{macro}
%
% We have to set the default for the handlers of defined keys, because they
% don't necessarily get defined before a list is parsed.
%    \begin{macrocode}
\let\ekvo@handle@defined@k\@gobble
\let\ekvo@handle@defined@kv\@gobbletwo
%    \end{macrocode}
%
%
% \subsection{Processing list elements}
%
% \begin{macro}[internal]{\ekvo@process@common}
%   All the key processing frontend macros use the same basic structure. |#1|
%   will be a simple test, deciding whether the list will really be parsed or
%   not, |#3| will be the \set, and |#2| will be the individual code of the
%   frontend macro which should be executed if both the test in |#1| is true and
%   the \set\ is defined.
%    \begin{macrocode}
\protected\def\ekvo@process@common#1#2#3%
  {%
    #1{\ekvo@do@with@set{#3}{#2}}%
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[internal]{\ekvo@process@list}
%   This macro only expands the list holding macro and forwards it to the
%   loop macro.
%    \begin{macrocode}
\protected\def\ekvo@process@list#1%
  {%
    \expandafter\ekvo@CurrentOption@loop\expandafter{#1}\ekvo@parse
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[internal]{\ekvo@parse}
%   This macro calls internals of |\ekvparse| such that the code splitting at
%   commas isn't executed, else this is equivalent to
%   |\ekvparse\ekvo@set@k\ekvo@set@kv{#1}|.
%    \begin{macrocode}
\protected\long\def\ekvo@parse#1%
  {%
    \ekv@expanded
      {\ekv@unexpanded{\ekvparse\ekvo@set@k\ekvo@set@kv}\expandafter}%
      \expandafter{\ekv@gobble@mark#1}\ekvo@tail
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[internal]{\ekvo@set@k,\ekvo@set@kv}
%   These two macros check whether the key is defined and if so call the handler
%   for defined keys and execute the key, else the handler for undefined keys is
%   called. They have to clean up a bit of code which is left by |\ekvo@parse|.
%    \begin{macrocode}
\protected\def\ekvo@set@k#1#2\ekvo@tail
  {%
    \ekv@ifdefined{\ekvo@name{#1}N}%
      {%
        \ekvo@handle@defined@k{#1}%
        \csname\ekvo@name{#1}N\endcsname
      }%
      {\ekvo@handle@undefined@k{#1}}%
  }
\protected\def\ekvo@set@kv#1#2#3\ekvo@tail
  {%
    \ekv@ifdefined{\ekvo@name{#1}}%
      {%
        \ekvo@handle@defined@kv{#1}{#2}%
        \csname\ekvo@name{#1}\endcsname{#2}%
      }%
      {\ekvo@handle@undefined@kv{#1}{#2}}%
  }
%    \end{macrocode}
% \end{macro}
%
%
% \subsection{List variable helpers}
%
% \begin{macro}[internal]{\ekvo@addto@list}
%   This macro is rather simple. If the list to which the |\CurrentOption|
%   should be added is empty we can just let the list to the |\CurrentOption|.
%   Else we have to expand the list once and the |\CurrentOption| once.
%    \begin{macrocode}
\protected\def\ekvo@addto@list#1%
  {%
    \ekvo@ifx@TF#1\@empty
      {\let#1\CurrentOption}%
      {%
        \edef#1%
          {%
            \unexpanded\expandafter{#1},%
            \unexpanded\expandafter{\CurrentOption}%
          }%
      }%
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[internal]{\ekvo@rmfrom@list,\ekvo@rmfrom@list@}
%   This works by looping over every list item and comparing it to
%   |\ekvo@curropt| which stores the real |\CurrentOption|. This is
%   comparatively slow, but works for items containing braces unlike what
%   \LaTeXe\ does. We could be faster for items not containing braces, though.
%    \begin{macrocode}
\protected\def\ekvo@rmfrom@list#1%
  {%
    \ekvo@ifx@F#1\@empty
      {%
        \let\ekvo@tmp@list\@empty
        \let\ekvo@curropt\CurrentOption
        \expandafter\ekvo@CurrentOption@loop\expandafter{#1}\ekvo@rmfrom@list@
        \let\CurrentOption\ekvo@curropt
        \let#1\ekvo@tmp@list
      }%
  }
\protected\long\def\ekvo@rmfrom@list@#1%
  {%
    \ekvo@ifx@F\CurrentOption\ekvo@curropt
      {\ekvo@addto@list\ekvo@tmp@list}%
  }
%    \end{macrocode}
% \end{macro}
%
%
% \subsection{Errors}
%
% \begin{macro}[internal]
%   {
%     \ekvo@err@undefined@key,\ekvo@err@value@required,
%     \ekvo@err@value@forbidden,\ekvo@err@undefined@set
%   }
%   Just some macros to throw errors in the few cases an error has to be thrown.
%    \begin{macrocode}
\protected\def\ekvo@err@undefined@key#1%
  {%
    \PackageError{expkv-opt}{Undefined key `#1' in set `\ekvo@setname'}{}%
  }
\protected\def\ekvo@err@value@required#1%
  {%
    \PackageError{expkv-opt}%
      {Value required for key `#1' in set `\ekvo@setname'}%
      {}%
  }
\protected\def\ekvo@err@value@forbidden#1%
  {%
    \PackageError{expkv-opt}%
      {Value forbidden for key `#1' in set `\ekvo@setname'}%
      {}%
  }
\protected\def\ekvo@err@undefined@set#1%
  {%
    \PackageError{expkv-opt}%
      {Undefined set `#1'}%
      {The set for which you try to parse options isn't defined in expkv.}%
  }
%    \end{macrocode}
% \end{macro}
%
%
% \subsection{User Interface}
%
% The user interface macros just put together the bits and pieces.
% \begin{macro}{\ekvoProcessLocalOptions}
%    \begin{macrocode}
\protected\def\ekvoProcessLocalOptions
  {%
    \ekvo@process@common
      {\ekv@ifdefined{opt@\@currname.\@currext}\@firstofone\@gobble}%
      {%
        \ekvo@set@handlers@local
        \expandafter
        \ekvo@process@list\csname opt@\@currname.\@currext\endcsname
        \AtEndOfPackage{\let\@unprocessedoptions\relax}%
      }%
  }
%    \end{macrocode}
% \end{macro}
% \begin{macro}{\ekvoProcessGlobalOptions}
%    \begin{macrocode}
\protected\def\ekvoProcessGlobalOptions
  {%
    \ekvo@process@common{\ekvo@ifx@F\@classoptionslist\relax}%
      {%
        \ekvo@set@handlers@global
        \ekvo@process@list\@classoptionslist
        \let\ekvo@handle@defined@k\@gobble
        \let\ekvo@handle@defined@kv\@gobbletwo
      }%
  }
%    \end{macrocode}
% \end{macro}
% \begin{macro}{\ekvoProcessUnusedGlobalOptions}
%    \begin{macrocode}
\protected\def\ekvoProcessUnusedGlobalOptions
  {%
    \ekvo@process@common{\ekvo@ifx@F\@unusedoptionlist\@empty}%
      {%
        \let\ekvo@tmp@list\@unusedoptionlist
        \ekvo@set@handlers@unusedglobal
        \ekvo@process@list\ekvo@tmp@list
        \let\ekvo@handle@defined@k\@gobble
        \let\ekvo@handle@defined@kv\@gobbletwo
      }%
  }
%    \end{macrocode}
% \end{macro}
% \begin{macro}{\ekvoProcessOptionsList}
%    \begin{macrocode}
\protected\def\ekvoProcessOptionsList#1%
  {%
    \ekvo@process@common{\ekvo@ifx@F#1\@empty}%
      {%
        \ekvo@set@handlers@list
        \ekvo@process@list#1%
      }%
  }
%    \end{macrocode}
% \end{macro}
% \begin{macro}{\ekvoUseUnknownHandlers}
%    \begin{macrocode}
\protected\def\ekvoUseUnknownHandlers#1#2%
  {%
    \let\ekvo@handle@undefined@k#1\relax
    \let\ekvo@handle@undefined@kv#2\relax
    \let\ekvo@if@need@handlers\ekvo@dont@need@handlers
  }
%    \end{macrocode}
% \end{macro}
%
% All user interface macros should be only used in the preamble.
%    \begin{macrocode}
\@onlypreamble\ekvoProcessLocalOptions
\@onlypreamble\ekvoProcessGlobalOptions
\@onlypreamble\ekvoProcessUnusedGlobalOptions
\@onlypreamble\ekvoProcessOptionsList
\@onlypreamble\ekvoUseUnknownHandlers
%    \end{macrocode}
% 
% \gobbledocstriptag
%</pkg>
%
% \end{implementation}^^A=<<
%
% \clearpage
% \PrintIndex
%
% \Finale
\endinput
%
^^A vim: ft=tex fdm=marker fmr=>>=,=<<