% \iffalse meta-comment
%
% Copyright (C) 2019-2026 by Pablo González L <pablgonz@educarchile.cl>
%
% This work 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
%
%  https://www.latex-project.org/lppl.txt
%
% and version 1.3c or later is part of all distributions of LaTeX version
% 2005/12/01 or later.
%
% This work is "maintained" (as per the LPPL maintenance status)
% by Pablo González Luengo.
%
% This work consists of the files scontents.dtx and
%                                 scontents.ins,
% and the derived files           scontents.sty,
%                                 scontents.tex,
%                                 t-scontents.mkiv and
%                                 scontents-code.tex.
%
%<*driver>
\documentclass[full]{l3doc}
\usepackage[svgnames]{xcolor}
\usepackage[sf,bf,compact,medium,pagestyles]{titlesec}
\usepackage{lastpage,microtype,attachfile2,multicol,listings,titletoc,fontawesome5}
\usepackage{graphicx}
\usepackage[english]{babel}
\usepackage[top=0.5in,bottom=0.3in,left=2in,right=0.7in,footskip=0.2in,headheight=1cm,headsep=0.27cm]{geometry}
% Set \parindent and \parskip
\setlength{\parindent}{0pt}
\setlength{\parskip}{\smallskipamount}
% Extra stretch before overflowing the line
\setlength{\emergencystretch}{2em}
% Only for arara... I like arara :)
\usepackage[scale=0.85]{comfortaa}
\definecolor{araracolor}{rgb}{0, 0.72, 0.28}
\newcommand{\araratext}[1]{{\small\normalfont\comfortaa\color{araracolor}\bfseries#1}}
\newcommand*\arara{\araratext{ar\kern-.03emar\kern-.03ema}}
% Fonts, libertine is only loaded for \LKeyTab
\usepackage[llscaled=0.95]{libertine}
\usepackage[osf,nomath,mono=false,ScaleSF=0.95,ScaleRM=0.95]{libertinus-otf}
% Set Monospace font, fix 'quotes' in verbatim
\usepackage{sourcecodepro}
\defaultfontfeatures[\ttfamily]
  {
    Numbers   = OldStyle,
    Scale     = 0.84249,
    Extension = .otf,
  }
\setmonofont[
    UprightFont       = *-Regular,
    ItalicFont        = *-RegularIt,
    BoldFont          = *-Medium,
    BoldItalicFont    = *-MediumIt,
    RawFeature        = {+zero,+ss01}]{SourceCodePro}
\newfontfamily\mysourcecodeprolight{SourceCodePro-Regular.otf}[
    Scale = 0.80,FakeStretch =0.75,
    FontFace = {m}{it}{Font =SourceCodePro-RegularIt.otf,Color=FF0000}]
\RenewDocumentCommand{\MacroLongFont}{}
  {
    \mysourcecodeprolight\small
  }
% Internal
\newfontfamily\mylmrotf{lmroman10-regular.otf}[NFSSFamily=lmrotf,Scale = 0.95]
\newfontfamily\mylmmotf{lmmono10-regular.otf}[NFSSFamily=lmmotf,Scale = 0.95]
% The character of visible space is now taken from Latin Modern Mono
% to prevent fonts in T1. The original definition for xetex/luatex is
% \def\verbvisiblespace{\usefont{OT1}{cmtt}{m}{n}\asciispace}
\def\verbvisiblespace{{\fontfamily{lmmotf}\fontshape{n}\selectfont\char"2423}}

% Math font
\usepackage{unicode-math}
\setmathfont[Scale = 0.95]{latinmodern-math.otf}
\newfontfamily\fetamontotf{ffmw10.otf}[
   Scale             = 0.95,%
   RawFeature        = {+latn,+rand,+kern,+size},%
   FontFace          = {b}{n}{ffmw10.otf},% fix replace font
   ]
% Index
\usepackage{imakeidx}
\indexsetup{level=\section,firstpagestyle=myheader,othercode=\pagestyle{myheader}}
% imakeidx also opens a write stream for the .idx file, and that conflicts
% with the one opened by l3doc. Here we close that write stream:
\ExplSyntaxOn
\iow_close:c { @indexfile }
% and later we will copy the write stream opened by imakeidx into \@indexfile
% so that entries written to both streams end up in the same file.
\makeindex[name=userdoc,options={-q ~ -s ~ gind.ist},columnsep=15pt,title={Index ~ of ~ Documentation}]
\makeindex[options={-q ~ -s ~ gind.ist},columnsep=15pt,title={Index ~ of ~ Implementation}]
\EnableCrossrefs
% \PageIndex, \CodelineIndex undoes what \PageIndex does
% \CodelineIndex tries to open another write stream for the index file. We don't
% want that, so we temporarily make \makeindex a no-op:
\cs_set_eq:NN \l__mydoc_tmp_makeindex_cs \makeindex
\cs_set_nopar:Npn \makeindex { }
\CodelineIndex
\cs_set_eq:NN \makeindex \l__mydoc_tmp_makeindex_cs
\DoNotIndex{\ , \1,\^}
\exp_args:Ne \DoNotIndex { \tl_to_str:n { \{ } }
\exp_args:Ne \DoNotIndex { \tl_to_str:n { \} } }
\exp_args:Ne \DoNotIndex { \tl_to_str:n { \begin } }
% \StartImplementation
\cs_new_protected:Npn \StartImplementation
  {
    \bool_set_true:N \l__codedoc_in_implementation_bool
  }
\bool_set_false:N \l__codedoc_in_implementation_bool
% Links and index
\newcommand{\HP}[1]{\emph{\hyperpage{#1}}\normalsize}
\cs_new_protected:Nn \__mydoc_sort_index:nn
  {
    \bool_if:NTF \l__codedoc_in_implementation_bool
      {
        \index{#1\actualchar#2|HP}
      }
      {
        \index[userdoc]{#1\actualchar#2|HP}
      }
  }
% Now, after imakeidx opens the write stream for the index file, we copy
% the reference to \@indexfile:
\cs_set_eq:cc { @indexfile } { \c_sys_jobname_str @idxfile }
\ExplSyntaxOff
% Package documented
\usepackage{scontents} % main
% LuaLaTeX syntax highlighter for l3doc (it also defines the color palette)
\usepackage{mylhmc}
\setmylhmc
  {
    module  = scontents,
    provide =
      { setupsc, newenvsc, Scontents, getstored, foreachsc, typestored,
        meaningsc, mergesc, countsc, cleanseqsc, scontents, endscontents,
        startscontents, stopscontents, verbatimsc, endverbatimsc,
        stopverbatimsc },
    key-path = {typemeaning,},
  }
% Colors
\definecolor{newlinkcolor}{HTML}{0A602C}
\definecolor{rulecolor}{rgb}{0.96,0.96,0.96}
% Get file info
\GetFileInfo{scontents.sty}
% Config hyperref
\hypersetup
  {
    allcolors          = newlinkcolor,
    colorlinks         = true,
    linktoc            = all,
    pdftitle           = {.:: The scontents package --- \fileinfo{} ::.},
    pdfauthor          = {Pablo González L},
    pdfsubject         = {Documentation for \fileversion{} [\filedate] },
    pdfkeywords        = {sequences, contents, external files, expl3, l3seq, store contents, tagged},
    bookmarksopenlevel = 1,
  }
% User level commands
\ExplSyntaxOn
% Logo with fetamont font
\NewDocumentCommand \pkglogo { }
  {
    \group_begin:
      \fetamontotf
        {
          \textcolor { module_name } { s }
          \textcolor { OrangeRed } { content }
          \textcolor { module_name } { s }
        }
    \group_end:
  }
% Custom \meta[...]{...}, \marg[...]{...} and \oarg[...]{...} with color
\NewDocumentCommand \mymeta { O{} m }
  {
    \__mydoc_meta_generic:Nnn \__mydoc_meta:n { #1 } { #2 }
  }
\NewDocumentCommand \mymarg { O{} m }
  {
    \__mydoc_meta_generic:Nnn \__mydoc_marg:n { #1 } { #2 }
  }
\NewDocumentCommand \myoarg { O{} m }
  {
    \__mydoc_meta_generic:Nnn \__mydoc_oarg:n { #1 } { #2 }
  }
% Variables and keys
\tl_new:N \l_userdoc_meta_font_tl
\keys_define:nn { userdoc / mymeta }
  {
    type      .choice:,
    type / tt .code:n    = \tl_set:Nn \l_userdoc_meta_font_tl { \ttfamily },
    type / rm .code:n    = \tl_set:Nn \l_userdoc_meta_font_tl { \rmfamily },
    type      .initial:n = tt,
    cf        .tl_set:N  = \l_userdoc_meta_color_tl,
    cf        .initial:n = keyname,
    ac        .tl_set:N  = \l_userdoc_meta_anglecolor_tl,
    ac        .initial:n = lightgray,
    sbc       .tl_set:N  = \l_userdoc_meta_brackcolor_tl,
    sbc       .initial:n = gray,
    cbc       .tl_set:N  = \l_userdoc_meta_bracecolor_tl,
    cbc       .initial:n = gray,
  }
% Internal commands
\cs_new_protected:Npn \__mydoc_meta_generic:Nnn #1 #2 #3
  {
    \group_begin:
      \keys_set:nn { userdoc / mymeta } { #2 }
      \color{ \l_userdoc_meta_color_tl }
      \l_userdoc_meta_font_tl
      #1 { #3 } % #1 is \__mydoc_meta:n, \__mydoc_marg:n or \__mydoc_oarg:n
    \group_end:
  }
\cs_new_protected:Npn \__mydoc_meta:n #1
  {
    \__mydoc_meta_angle:n { \textlangle }
    \__mydoc_meta_meta:n { #1 }
    \__mydoc_meta_angle:n { \textrangle }
  }
\cs_new_protected:Npn \__mydoc_marg:n #1
  {
    \__mydoc_meta_brace:n { \textbraceleft }
    \__mydoc_meta:n { #1 }
    \__mydoc_meta_brace:n { \textbraceright }
  }
\cs_new_protected:Npn \__mydoc_oarg:n #1
  {
    \__mydoc_meta_brack:n { [ }
    \__mydoc_meta:n { #1 }
    \__mydoc_meta_brack:n { ] }
  }
\cs_new_protected:Npn \__mydoc_meta_meta:n #1
  {
    \textnormal{\textit{#1}}
  }
\cs_new_protected:Npn \__mydoc_meta_angle:n #1
  {
    \group_begin:
      \fontfamily{lmrotf}\fontshape{n}\selectfont
      \textcolor{\l_userdoc_meta_anglecolor_tl}{#1}
    \group_end:
  }
\cs_new_protected:Npn \__mydoc_meta_brace:n #1
  {
    \group_begin:
      \color{\l_userdoc_meta_bracecolor_tl}
        #1
    \group_end:
  }
\cs_new_protected:Npn \__mydoc_meta_brack:n #1
  {
    \textcolor{\l_userdoc_meta_brackcolor_tl}{#1}
  }
% Color the characters matched by the regex #2 in the token list #1 with the
% palette color #3 (only the first match, or every match)
\cs_new_protected:Npn \__mydoc_color_once:Nnn #1 #2 #3
  {
    \regex_replace_once:nnN { ( #2 ) } { \c{textcolor}\cB\{#3\cE\}\cB\{\1\cE\} } #1
  }
\cs_new_protected:Npn \__mydoc_color_all:Nnn #1 #2 #3
  {
    \regex_replace_all:nnN { ( #2 ) } { \c{textcolor}\cB\{#3\cE\}\cB\{\1\cE\} } #1
  }
% \envexamp{m}: syntax of an environment, \begin{env}[key=val] ... \end{env}
\newsavebox{\boxexaenv}
\NewDocumentCommand \envexamp { m }
  {
    \begin{lrbox}{\boxexaenv}%
      \begin{minipage}[t]{\marginparwidth}%
        \raggedright\ttfamily\small
        \textcolor{gray}{\textbackslash begin\{\textcolor{module_name}{#1}\}\myoarg
        [type=tt,sbc=gray,ac=lightgray,cf=keyname]{key\textnormal{\textcolor{gray}{=}}val}}\par%
        \hspace{0.5cm}\mymeta[type=tt,ac=lightgray,cf=gray]{body~env}\par%
        \textcolor{gray}{\textbackslash end\{\textcolor{module_name}{#1}\}}\par
      \end{minipage}%
    \end{lrbox}%
    \usebox{\boxexaenv}
  }
% \envexaplain{O{} m O{end}}: syntax of a pseudo environment in plain TeX
% (\scontents ... \endscontents) or ConTeXt (\startscontents ... \stopscontents)
\NewDocumentCommand \envexaplain { O{} m O{end} }
  {
    \begin{lrbox}{\boxexaenv}%
      \begin{minipage}[t]{\marginparwidth}%
        \raggedright\ttfamily\small
        \textcolor{module_name}{\textbackslash#1#2}\myoarg
        [type=tt,sbc=gray,ac=lightgray,cf=keyname]{key\textnormal{\textcolor{gray}{=}}val}\par%
        \hspace{0.5cm}\mymeta[type=tt,ac=lightgray,cf=gray]{body~env}\par%
        \textcolor{module_name}{\textbackslash#3#2}\par
      \end{minipage}%
    \end{lrbox}%
    \usebox{\boxexaenv}
  }
% \cmdexamp{o m o m o}
\tl_new:N \l__mydoc_cmdexamp_tl
\NewDocumentCommand \cmdexamp { o m o m o }
  {
    \group_begin:
      \small\ttfamily
      \textcolor{module_name}{\textbackslash#2}
      \IfValueT{#1}{ \textcolor{star}{#1} }
      \IfValueT{#3}
        {
          \tl_set:Nn \l__mydoc_cmdexamp_tl { #3 }
          \regex_replace_once:nnN { (\*) } { \c{texttt}\cB\{\c{textcolor}\cB\{star\cE\}\cB\{\1\cE\} \cE\} } \l__mydoc_cmdexamp_tl
          \myoarg[type=tt,sbc=gray,ac=lightgray,cf=keyname]{\tl_use:N \l__mydoc_cmdexamp_tl}
        }
      \IfValueTF{#5}
        {
          \mymeta[ac=gray,type=tt,cf=star]{#5}%
          \mymeta[type=tt,ac=gray,cf=keyname]{#4}
          \mymeta[ac=gray,type=tt,cf=star]{#5}%
        }
        { \mymarg[type=tt,cbc=gray,ac=lightgray,cf=keyname]{#4} }
      \par
    \group_end:
  }
% Index entries for the keys. #1 is the target: 'env' (environments in
% general) or the name of a command (printed with a backslash). #2 is the key.
\cs_new_protected:Npn \__mydoc_key_index:nn #1 #2
  {
    \str_case:nnF {#1}
      {
        { env }
          {
            \__mydoc_sort_index:nn { Keys }
              { Keys~for~environments~provided~by~\pkglogo :> \texttt {#2} }
          }
      }
      {
        \__mydoc_sort_index:nn { Keys }
          { Keys~for~\texttt { \textbackslash #1 }~provided~by~\pkglogo :> \texttt {#2} }
      }
  }
\cs_new_protected:Npn \__mydoc_key_index_list:nn #1 #2
  {
    \clist_map_inline:nn {#1}
      { \__mydoc_key_index:nn {##1} {#2} }
  }
% Key line: name hanging in the margin, value, and default
% \__mydoc_key_line:Nnnn {boolean} {key} {value} {default}
\cs_new_protected:Npn \__mydoc_key_line:Nnnn #1 #2 #3 #4
  {
    \group_begin:
      \noindent
      \mode_leave_vertical:
      \hbox_to_wd:nn { -\marginparsep }
        {
          \hss
          \textcolor { keyname } { \small \ttfamily {#2} }
        }
      \IfBooleanTF {#1}
        {
          \hphantom { \textcolor { white } { \, \bfseries \texttt{=} } \, {} }
          \mymeta [ type=tt, cbc=gray, ac=lightgray, cf=lightgray ] { \small {#3} }
        }
        {
          \textcolor { gray } { \, \bfseries \texttt{=} } \, {}
          \mymarg [ type=tt, cbc=gray, ac=lightgray, cf=keyname ] { \small {#3} }
        }
      \hfill
      \textcolor { gray } { \small \textsf { default } :~ \emph{#4} }
      \par
    \group_end:
  }
% \keyexampcmd{s m m m o}, the optional #5 is a clist of targets for the
% index (env or a command name); without it there is no index entry
\NewDocumentCommand \keyexampcmd { s m m m o }
  {
    \__mydoc_key_line:Nnnn #1 {#2} {#3} {#4}
    \IfValueT {#5}
      { \__mydoc_key_index_list:nn {#5} {#2} }
  }
% \mykey{o m}, the optional #1 is a clist of targets for the index
\tl_new:N \l__mydoc_name_tl
\NewDocumentCommand \mykey { o m }
  {
    \group_begin:
      \tl_set:Nn \l__mydoc_name_tl { #2 }
      \__mydoc_color_once:Nnn \l__mydoc_name_tl { \* } { star }
      \textcolor { keyname } { \ttfamily \tl_use:N \l__mydoc_name_tl }
      \IfValueT {#1}
        { \__mydoc_key_index_list:nn {#1} { \tl_use:N \l__mydoc_name_tl } }
    \group_end:
  }
% \mypkg{s O{} m}, use the optional argument [no-index] to skip the index
\NewDocumentCommand \mypkg { s O{} m }
  {
    \group_begin:
      \IfBooleanTF {#1}
        { \pkglogo }
        { \textcolor { pkgname } { \textbf { \texttt {#3} } } }
      \str_if_eq:nnF {#2} { no-index }
        { \__mydoc_sort_index:nn { packages } { Packages~:>~\texttt {#3} } }
    \group_end:
  }
% \myenv{s O{} m}, use the optional argument [no-index] to skip the index
\NewDocumentCommand \myenv { s O{} m }
  {
    \IfBooleanTF {#1}
      {
        \tl_set:Nn \l__mydoc_name_tl { #3 }
        \__mydoc_color_once:Nnn \l__mydoc_name_tl { \* } { star }
        \textcolor { module_name } { \ttfamily { \tl_use:N \l__mydoc_name_tl } }
        \str_if_eq:nnF {#2} { no-index }
          {
            \__mydoc_sort_index:nn { environment }
              { Environments~provided~by~\pkglogo :> \texttt { \tl_use:N \l__mydoc_name_tl } }
          }
      }
      {
        \textcolor { pkgname } { \ttfamily {#3} }
        \str_if_eq:nnF {#2} { no-index }
          { \__mydoc_sort_index:nn { environment } { Environments~:>~\texttt {#3} } }
      }
  }
% \ics{s m}
\NewDocumentCommand \ics { s m }
  {
    \IfBooleanTF {#1}
      {
        \tl_set:Nn \l__mydoc_name_tl { #2 }
        \__mydoc_color_once:Nnn \l__mydoc_name_tl { \* } { star }
        \textcolor { module_name } { \ttfamily \textbackslash { \tl_use:N \l__mydoc_name_tl } }
        \__mydoc_sort_index:nn { Commands }
          { Commands~provided~by~\pkglogo :> \texttt { \textbackslash #2 } }
      }
      {
        \textcolor { latex_cmd } { \ttfamily \textbackslash {#2} }
        \__mydoc_sort_index:nn {#2} { \texttt { \textbackslash #2 } }
      }
  }
% \myfile{m}
\NewDocumentCommand \myfile { m }
  {
    \group_begin:
      \tl_set:Nn \l__mydoc_name_tl { #1 }
      \__mydoc_color_all:Nnn \l__mydoc_name_tl { \d } { number }
      \__mydoc_color_all:Nnn \l__mydoc_name_tl { \. } { star }
      \textcolor { filename } { \ttfamily \tl_use:N \l__mydoc_name_tl }
    \group_end:
  }
% \myattachfile{s m}, the star version attaches only the \texttt{.tex} file
\NewDocumentCommand \myattachfile { s m }
  {
    \group_begin:
      \IfBooleanTF { #1 }
        {
          \IfFileExists { #2.tex }
            {
              Source~file~
              \textattachfile[color=newlinkcolor,print=false]{#2.tex}{\faFile*[regular]}.
            }
            { }
        }
        {
          \IfFileExists { #2.pdf }
            {
              Source~file~
              \textattachfile[color=newlinkcolor,print=false]{#2.tex}{\faFile*[regular]}~
              and~\emph{tagged}~\texttt{PDF}~
              \textattachfile[color=newlinkcolor,print=false]{#2.pdf}{\faFilePdf[regular]}.
            }
            { }
        }
    \group_end:
  }
% Space before the function environment
\hook_gput_code:nnn { env/function/before } { mydoc }
  {
    \vspace* { -\baselineskip }
  }
% Icons in the margin for the environment important (internal use)
\cs_new_protected:Npn \__mydoc_margin_icon:n #1
  {
    \par
    \mode_leave_vertical:
    \skip_horizontal:n { -0.5 \marginparsep }
    \hbox_overlap_left:n
      {
        \hbox_to_wd:nn { \marginparsep }
          {
            \hss
            \textcolor { module_at } { #1 }
          }
      }
    \skip_horizontal:n { 0.5 \marginparsep }
  }
% Environment for notes
\NewDocumentEnvironment { important } { s }
  {
    \par\addvspace { \smallskipamount }
    \small\sffamily
    \IfBooleanTF { #1 }
      {
        \__mydoc_margin_icon:n { \footnotesize \faIcon { bomb } }
      }
      {
        \__mydoc_margin_icon:n { \scriptsize \reflectbox { \faIcon { tag } } }
      }
    \ignorespaces
  }
  { }
% Parse and format an e-mail address
\seq_new:N \l__mydoc_email_seq
\cs_new_protected:Npn \__mydoc_format_email:n #1
  {
    \seq_set_split:Nnn \l__mydoc_email_seq { @ } { #1 }
    \href { mailto:#1 }
      {
        \ttfamily
        \seq_item:Nn \l__mydoc_email_seq { 1 }
        \textcolor { arroba } { \footnotesize @ }
        \seq_item:Nn \l__mydoc_email_seq { 2 }
      }
  }
\NewDocumentCommand \email { m }
  {
    \__mydoc_format_email:n { #1 }
  }
% Don't copy numbers in code example
\newcommand*{\noaccsupp}[1]
  {
    \__mylhmc_luafun_actual_text_begin: #1 \__mylhmc_luafun_actual_text_end:
  }
\ExplSyntaxOff
% Custom verbatimsc, used by \typestored in this documentation
\ExplSyntaxOn
\cs_undefine:N \verbatimsc
\cs_undefine:N \endverbatimsc
\ExplSyntaxOff
\lstnewenvironment{verbatimsc}
  {
    \lstset{
       language   =,%
       basicstyle = \ttfamily\small,
       gobble     = 2,%
           }
   }{}
% Create a language for documentation
\lstdefinelanguage{scontents-doc}{
    texcsstyle    = *,%
    escapechar    = Ç,%
    extendedchars = true,%
    keepspaces    = true,%
    stringstyle   = {\color{red}},%
    basicstyle    = \ttfamily\small,%
    alsoletter    = {-,@,.},%
% comments
    morecomment   = [l]{\%},%
    commentstyle  = \ttfamily\small\color{comment},%
% Important \documentclass \begin \end \makeatletter \NewDocumentCommand
    keywordstyle  = [1]{\bfseries\color{structure}},%
    keywords      = [1]{begin, end, document, documentclass, makeatletter, makeatother,%
                    ExplSyntaxOn, ExplSyntaxOff, NewDocumentCommand, RenewDocumentCommand},%
% Other words \usepackage
    keywordstyle  = [2]{\color{pkgstruct}},%
    keywords      = [2]{usepackage, RequirePackage, ProvidesExplPackage, input, usemodule},%
% Other words 3 tagpdf
    keywordstyle  = [3]{\color{mathtag}},%
    keywords      = [3]{DocumentMetadata, IfDocumentMetadataTF},%
% Other words 4 (LaTeX2e and expl3)
    keywordstyle  = [4]{\color{latex_cmd}},%
    keywords      = [4]{section, subsection, lstinline, Verb, verb, macro, makebox, detokenize,%
                    meaning, definetyping, lstset, small, ttfamily, tiny, color, scantokens,%
                    setlength, pagestyle, definecolor, obeyedline, item, par, parindent,%
                    newtheorem, newenvironment, DefineVerbatimEnvironment, lstnewenvironment,%
                    newminted, VerbatimEnvironment, dospecials, char, jobname, setuptyping,%
                    peek_charcode_ignore_spaces, cs_argument_spec, cs_parameter_spec,%
                    regex_replace_all, tl_replace_all, tex_scantokens, tex_endinput,%
                    file_input_stop, peek_charcode, cs_undefine, tl_rescan, int_to_roman,%
                    tl_retokenize, int_step_tokens, keys_set, l_keys_key_str, tl_gset_rescan,%
                    contextlmtxmode},%
% Other words 5 (package name)
    keywordstyle  = [5]{\bfseries\color{pkgname}},%
    keywords      = [5]{listings, minted, fancyvrb, fvextra, tcolorbox},%
% Reserved words 6 (document class)
    keywordstyle  = [6]{\bfseries\color{clsname}},%
    keywords      = [6]{article},%
% Reserved words 7 (scontents cmd)
    keywordstyle  = [7]{\color{module_name}},%
    keywords      = [7]{scontents, Scontents, getstored, typestored, verbatimsc, mergesc,%
                    endverbatimsc, countsc, meaningsc, foreachsc, newenvsc, setupsc, cleanseqsc,%
                    endverbatim, endscontents, startscontents, stopscontents, scontents.tex,%
                    startverbatimsc, stopverbatimsc, myenvstore},%
% Reserved words 8 (keyname) KEYS
    keywordstyle  = [8]{\color{keyname}},%
    keywords      = [8]{store-cmd, store-env, print-env, print-cmd, write-env, verb-font,%
                    start, stop, wrapper, sep, step, before, after, write-out, write-cmd,%
                    overwrite, width-tab, force-eol, store-all, print-all, debug-var, 1-end, remember,%
                    I, J, M, L, Ascheol, lang, pdfversion, pdfstandard, testphase, tagging},%
% Reserved words 9 (values)
    keywordstyle  = [9]{\color{ltcmd_arg}},%
    keywords      = [9]{true, false, myseq, inner, outer, env, Verbatim, en-US, ua-2, on},%
% Reserved words 10 (signature)
    keywordstyle  = [10]{\color{sigargs}},%
    keywords      = [10]{NTF, N, x, e, n, nn, nnn, D, Nnn},%
% Reserved words 12 (plain TeX or internal)
    keywordstyle  = [12]{\color{danger}},%
    keywords      = [12]{let, @undefined, def, @bsphack, @esphack, @ifpackagelater,%
                    ver@xparse.sty, ver@scontents.sty, l__scontents_ver_str, do@noligs,%
                    MakeFile},%
% Reserved words 13 (message names)
    keywordstyle  = [13]{\color{red}},%
    keywords      = [13]{already-loaded, cmd-key-unknown, cmd-key-value-unknown,%
                    empty-argument-command, empty-environment, empty-store-name,%
                    empty-variable, env-already-defined, env-key-unknown,%
                    env-key-value-unknown, expl-too-old, index-out-of-range,%
                    junk-after-begin, luametatex, mergesc-missing-key, multiple-begin,%
                    not-writing, overwrite-file, positive-integer, remember-latex-only,%
                    remember-rerun, remember-undefined, rescanning-text,%
                    undefined-storage, writing-file},%
% literate
    literate      =*{\{}{{{\color{brace}{\char`\{}}}}{1}
                    {\}}{{{\color{brace}{\char`\}}}}}{1}
                    {\|}{{{\color{gray}{\char`\|}}}}{1}
                    {\$}{{{\color{math}{\char`\$}}}}{1}
                    {\#}{{{\color{argument}{\char`\#}}}}{1}
                    {[}{{\textcolor{bracket}{[}}}{1}
                    {]}{{\textcolor{bracket}{]}}}{1}
                    {,}{{\textcolor{gray}{,}}}{1}
                    {;}{{\textcolor{gray}{;}}}{1}
                    {:}{{\textcolor{signature}{:}}}{1}
                    {`}{{\textcolor{backtick}{\textasciigrave}}}{1}
                    {\&}{{\textcolor{gray}{\&}}}{1}
                    {>}{{\textcolor{quote}{\guillemotright}}}{1}
                    {<}{{\textcolor{quote}{\guillemotleft}}}{1}
                    {*}{{\textcolor{star}{*}}}{1}
                    {\^}{{\textcolor{keyname}{\textasciicircum}}}{1}
                    {0}{{\textcolor{argnum}{0}}}{1}
                    {1}{{\textcolor{argnum}{1}}}{1}
                    {2}{{\textcolor{argnum}{2}}}{1}
                    {3}{{\textcolor{argnum}{3}}}{1}
                    {4}{{\textcolor{argnum}{4}}}{1}
                    {5}{{\textcolor{argnum}{5}}}{1}
                    {6}{{\textcolor{argnum}{6}}}{1}
                    {7}{{\textcolor{argnum}{7}}}{1}
                    {8}{{\textcolor{argnum}{8}}}{1}
                    {9}{{\textcolor{argnum}{9}}}{1}
                    {.0}{{\textcolor{argnum}{.0}}}{2}% Following is to ensure that only periods
                    {.1}{{\textcolor{argnum}{.1}}}{2}% followed by a digit are changed.
                    {.2}{{\textcolor{argnum}{.2}}}{2}
                    {.3}{{\textcolor{argnum}{.3}}}{2}
                    {.4}{{\textcolor{argnum}{.4}}}{2}
                    {.5}{{\textcolor{argnum}{.5}}}{2}
                    {.6}{{\textcolor{argnum}{.6}}}{2}
                    {.7}{{\textcolor{argnum}{.7}}}{2}
                    {.8}{{\textcolor{argnum}{.8}}}{2}
                    {.9}{{\textcolor{argnum}{.9}}}{2}
                    {=}{{\textcolor{compare}{=}}}{1},%
}[keywords,tex,comments,strings]% end language
% \begin{examplecode}[key=val]...\end{examplecode}
\lstnewenvironment{examplecode}[1][]{%
\lstset{
    language    = scontents-doc,%
    stringstyle = {\color{red}},%
    basicstyle  = \ttfamily\small,%
    columns     = fullflexible,%
    fontadjust  = true,%
    aboveskip   = 8pt,%
    belowskip   = 5pt,%
    rulecolor   = \color{gray!50},%
    framesep    = \fboxsep,%
    framerule   = \fboxrule,%
    xleftmargin = \dimexpr\fboxsep+\fboxrule\relax,%
    xrightmargin= \dimexpr\fboxsep+\fboxrule\relax,%
           #1,%
    }% close lstset
}{}% close examplecode
% \lstinline[style=inline]|...|
\lstdefinestyle{inline}
  {
    language    = scontents-doc,%
    upquote     = true,%
    numbersep   = 1em,%
    numberstyle = \tiny\color{lightgray}\noaccsupp,%
    literate    =*{\%}{{\textcolor{percent}{\%}}}{1}
  }
% Set default \lstinline style
\lstset{style=inline}
% Remove `"` and `|` for short verbatim defined in l3doc, then set short |...|
\AtBeginDocument
  {
    \DeleteShortVerb \"
    \DeleteShortVerb \|
    \lstMakeShortInline[language=scontents-doc,basicstyle=\ttfamily]\|
  }
% Configuration titleps and titlesec
\settitlemarks{section}
\renewpagestyle{plain}[\color{keyname}\small\sffamily]{%
\setfoot{\rlap{\hskip\dimexpr-\oddsidemargin-1in\relax%
         \parbox{1.93\paperwidth}{\hfil\thepage\,/\,\pageref{LastPage}}}}%
        {}%
        {}%
}
\newpagestyle{myheader}[\color{keyname}\small\sffamily]{%
\renewcommand\makeheadrule{%
\rlap{\hskip\dimexpr-\oddsidemargin-1in\relax
      \color{rulecolor}\rule[0.3cm]{\paperwidth}{0.7cm}}\hss
}
\setfoot{\rlap{\hskip\dimexpr-\oddsidemargin-1in\relax%
         \parbox{1.93\paperwidth}{\hfil\thepage\,/\,\pageref{LastPage}}}}%
        {\parbox{\textwidth}{\raggedright \textcolor{gray}{\raisebox{-1pt}{\textcopyright}{}2019--2026 by Pablo González L}}}%
        {}%
\sethead{\llap{\raisebox{0.55cm}{\parbox{\dimexpr\oddsidemargin+1in\relax}{\makebox[0pt][l]{\hspace{15pt}\pkglogo\space\fileversion}}}}}
        {\raisebox{0.55cm}{\parbox{\textwidth}{\hspace*{-\oddsidemargin}\centering\small\S.\thesection\space\sectiontitle}}}%
        {}%
}
\titlecontents{section}[0mm]{}%
    {\bfseries\contentspush{\makebox[5mm][l]{\thecontentslabel\hfill}}}%
    {\hspace*{-5mm}}% numberless
    {\hspace{0.25em}\titlerule*[6pt]{.}\contentspage}%
\titlecontents{subsection}[5mm]{}%
    {\contentspush{\makebox[6mm][l]{\thecontentslabel\hfill}}}
    {\hspace*{-11mm}}% numberless
    {\hspace{0.25em}\titlerule*[6pt]{.}\contentspage}%
% Table of contents
\ExplSyntaxOn
\cs_new_eq:Nc \__mydoc_mkboth:nn { @mkboth }
\cs_new_eq:Nc \__mydoc_starttoc:n { @starttoc }
\RenewDocumentCommand \tableofcontents { }
  {
    \group_begin:
    % Restore the l3doc \parskip locally (only for the TOC)
    \skip_set:Nn \parskip { 0pt~plus~3pt~minus~0pt }
    \section*
      {
        \contentsname \quad
          {
            \color { gray }
            \leaders \hrule height 5pt depth -4.4pt \hfill
          }
      }
    \__mydoc_mkboth:nn { \text_uppercase:n { \contentsname } } { \text_uppercase:n { \contentsname } }
    \vspace* { -14pt }
    \dim_set:Nn \columnsep { 10pt }
    \begin{multicols}{2}
      \__mydoc_starttoc:n { toc }
    \end{multicols}
    \vspace* { -3pt }
      {
        \color { gray }
        \hrule height 0.6pt
      }
    \vspace* { 5pt }
    \group_end:
  }
% \thanks
\cs_new:Npn \__mydoc_fnsymbol:n #1
  {
    \ensuremath
      {
        \int_case:nnF { #1 }
          {
            { 0 } { }
            { 1 } { \textcolor { module_name } { * } }
            { 2 } { \textcolor { module_name } { \dagger } }
            { 3 } { \ddagger }
            { 4 } { \mathsection }
            { 5 } { \mathparagraph }
            { 6 } { \| }
            { 7 } { ** }
            { 8 } { \dagger \dagger }
            { 9 } { \ddagger \ddagger }
          }
          { \use:c { @ctrerr } }
      }
  }
\hook_gput_code:nnn { begindocument } { scontents }
  {
    \cs_set_eq:cN { @fnsymbol } \__mydoc_fnsymbol:n
  }
\ExplSyntaxOff
\begin{document}
  \DocInput{\jobname.dtx}
\end{document}
%</driver>
% \fi
%
% \title{
%    \scalebox{1.72}{\pkglogo}\\[1pt]
%    \Large
%    \textcolor{gray}{\fetamontotf{stores} \hologo{LaTeX} \fetamontotf{contents}}\\[3pt]
%    \fileversion \quad \filedate\thanks{
%    This file describes a documentation for \fileversion, last revised
%    \filedate.}\\[25pt]
%    \author{
%    \large
%    \raisebox{-1pt}{\textcopyright}{}2019--2026 by Pablo González L\thanks{
%    E-mail: \textcolor{OrangeRed}{\textsf{\guillemotleft}}\email{pablgonz@educarchile.cl}\textcolor{OrangeRed}{\textsf{\guillemotright}}.
%       }%
%    }
% \small
% \textsc{ctan}: \url{https://www.ctan.org/pkg/scontents}\\
% \textcolor{gray}{\scriptsize\faIcon[regular]{github}}\,\,\,\url{https://github.com/pablgonz/scontents}
% \vspace*{-2cm}
% }
% \date{}
% \maketitle
%
% \begin{scontents}[store-env=abstract, print-env=true]
% \begin{abstract}
% This package allows to store \hologo{LaTeX} code, including \enquote{\emph{verbatim}},
% in \mymeta{sequences} using the \mypkg{l3seq} module of \mypkg{expl3}. The \mymeta{stored
% content} can be used as many times as desired in the document, additionally you can write
% to \mymeta{external files} or show it in \mymeta{verbatim style}.
% \end{abstract}
% \end{scontents}
%
% \tableofcontents
%
% \section{Description of the package}
%
% \begin{scontents}[store-env=description, print-env=true]
% The \mypkg*[no-index]{scontents} package allows to \mymeta{store contents} in \mymeta{sequences}
% or \mymeta{external files}. In some ways it is similar to the \mypkg{filecontentsdef}
% package, with the difference in which the \mymeta{content} is stored. The idea behind
% this package is to get an approach to \hologo{ConTeXt} \emph{\enquote{buffers}} by
% making use of \mymeta{sequences}.
% \end{scontents}
%
% \section{Motivation and Acknowledgments}
%
% In \hologo{LaTeX} there is no direct way to record content for later use, although
% you can do this using |\macro|, recording \mymeta{verbatim content}  is a
% problem, usually you can avoid this by creating external files or boxes.
%
% The general idea of this package is to try to imitate this implementation
% \enquote{\emph{buffers}} that has \hologo{ConTeXt} which allows you to save content in
% memory, including \emph{verbatim}, to be used later. The \mypkg{filecontentsdef}\cite{filecontentsdef}
% package solves this problem and since \mypkg{expl3}\cite{expl3} has an excellent way to manage data,
% ideas were combined giving rise to this package.
%
% This package would not be possible without the great work of \textsc{Jean
% Fran\c{c}ois Burnol} who was kind enough to take my requirements into account
% and add the \myenv{filecontentsdefmacro} environment to \mypkg{filecontentsdef} package.
% Also a special thanks to Phelype Oleinik who has collaborated and adapted a large part of the code and
% all \hologo{LaTeX} team for their great work and to the different members
% of the \href{https://tex.stackexchange.com}{TeX-SX} community who have provided
% great answers and ideas. Here a note of the main ones:
%
% \begin{enumerate}[left=0pt, labelsep=5pt, noitemsep, nosep, label=\small\arabic*.]
% \item \href{https://tex.stackexchange.com/q/45946/7832}{Stack datastructure using LaTeX}
%
% \item \href{https://tex.stackexchange.com/q/5338/7832}{LaTeX equivalent of ConTeXt buffers}
%
% \item \href{https://tex.stackexchange.com/q/215563/7832}{Storing an array of strings in a command}
%
% \item \href{https://tex.stackexchange.com/q/184503/7832}{Collecting contents of environment and store them for later retrieval}
%
% \item \href{https://tex.stackexchange.com/q/373647/7832}{Collect contents of an environment (that contains verbatim content)}
% \end{enumerate}
%
% \begin{important}*
% Starting with version 2.3 the \mypkg*[no-index]{scontents} package is fully
% compatible with \emph{tagged} \texttt{PDF}\cite{tagpdf} and will have \LaTeX{}
% release 2026-11-01 (\TeX{} Live 2026) and update \mypkg{expl3} release as a minimum requirement.
% \end{important}
%
% \thispagestyle{plain}
% \pagestyle{myheader}
%
% \section{License and Requirements}\label{sec:licence}
%
% Permission is granted to copy, distribute and/or modify this software under
% the terms of the LaTeX Project Public License (lppl), version 1.3 or later
% (\url{https://www.latex-project.org/lppl.txt}). The software has the status
% \enquote{maintained}.
%
% The package \mypkg*[no-index]{scontents} requires an updated version of \LaTeX{} to work
% (minimum required to \LaTeX{} release 2026-11-01 and \mypkg{expl3} update).
% This package can be used with |plain|, |context|, |xelatex|, |lualatex|, |pdflatex|
% and the classical workflow |latex>dvips>ps2pdf|.
%
% \section{The \texttt{scontents} package}\label{sec:pkgscontents}
%
% \subsection{Installation}
%
% The package \mypkg*[no-index]{scontents} is present in \hologo{TeX} Live and \hologo{MiKTeX},
% use the package manager to install. For manual installation, download
% \href{https://mirrors.ctan.org/macros/latex/contrib/scontents.zip}{scontents.zip}
% and unzip it, run \lstinline[language=scontents-doc,basicstyle=\ttfamily]+luatex scontents.ins+
% and move all files to appropriate locations, then run |mktexlsr|. To produce the documentation
% with source code run \lstinline[language=scontents-doc,basicstyle=\ttfamily]+luatex scontents.ins+ and
% |lualatex scontents.dtx| three times.
%
% \iffalse
%<*example>
% \fi
\begin{examplecode}[frame=single,language={}]
  scontents.tex       >  TDS:tex/generic/scontents/
  scontents-code.tex  >  TDS:tex/generic/scontents/
  scontents.sty       >  TDS:tex/latex/scontents/
  t-scontents.mkiv    >  TDS:tex/context/third/scontents/
  scontents.pdf       >  TDS:doc/latex/scontents/
  README.md           >  TDS:doc/latex/scontents/
  scontents.dtx       >  TDS:source/latex/scontents/
  scontents.ins       >  TDS:source/latex/scontents/
\end{examplecode}
% \iffalse
%</example>
% \fi
%
% \subsection{Loading and options}
%
% The package is loaded in the usual way:
%
% \subsubsection*{For \hologo{LaTeX} users}
%
% \iffalse
%<*example>
% \fi
\begin{examplecode}[frame=single]
\usepackageÇ\small\myoarg{key \textnormal{\textcolor{gray}{=}} val}Ç{scontents}
\end{examplecode}
% \iffalse
%</example>
% \fi
%
% \subsubsection*{For \hologo{plainTeX} users}
%
% \iffalse
%<*example>
% \fi
\begin{examplecode}[frame=single]
\input scontents.tex
\end{examplecode}
% \iffalse
%</example>
% \fi
%
% \subsubsection*{For \hologo{ConTeXt} users}
%
% \iffalse
%<*example>
% \fi
\begin{examplecode}[frame=single]
\usemodule{scontents}
\end{examplecode}
% \iffalse
%</example>
% \fi
%
% \begin{important}*
% The package options are not available for \hologo{plainTeX} and
% \hologo{ConTeXt} and must be passed using |\setupsc| (\S\ref{subsec:confopt}).
% \hologo{ConTeXt} users should use |-luatex|, the implementation does
% not support LuaMetaTeX.
% \end{important}
%
% \subsection{The TAB character}\label{subsec:tabcharacter}
%
% Some users use the horizontal \texttt{TAB} `\LKeyTab' character from
% keyboard to indent the source code of the document and depending on the text editor
% used, some will use real \texttt{TAB} (\emph{hard tabs}), others with
% \emph{soft tabs} (\verb*+  + or \verb*+    +) or both.
%
% At first glance it may seem the same, but the way in which \texttt{TAB} character
% (\emph{hard tabs}) are processed according to the context in which they are found within
% a file, both in \mymeta{reading}\footnote{Check the answer given by Ulrich Diez
% in \href{https://tex.stackexchange.com/a/508103/7832}{Keyboard TAB
% character in argument v (xparse)}.} and \mymeta{writing}\footnote{Check the answer
% given by Enrico Gregorio in \href{https://tex.stackexchange.com/a/58740/7832}{How to output a
% tabulation into a file}.} are different and may have adverse consequences.
%
% In a standard \hologo{LaTeX} document, the character \texttt{TAB} `\LKeyTab'
% are treated as explicit spaces (in most contexts) and is the behavior when
% \mymeta{stored content}, but when \mymeta{writing files} these are preserved.
%
% With a \hologo{TeX} Live distribution, the \texttt{TAB} character is \emph{printable}
% for |latex|, |pdflatex| and |lualatex|, but if you use |xelatex| you
% must add the |-8bit| option on the command
% line, otherwise you will get \hologo{TeX} character \texttt{TAB} `\myhlc|^^I|'
% in the \mymeta{output file}.
%
% As a general recommendation \emph{\enquote{Do not use \texttt{TAB} character unless strictly
% necessary}}, for example within a \emph{\enquote{verbatim environment}} that supports
% this character such as \myenv{Verbatim} of the packages \mypkg{fancyvrb}\cite{fancyvrb},
% \mypkg{fvextra}\cite{fvextra} or \myenv{lstlisting} of the package \mypkg{listings}\cite{listings}
% or when you want to generate a |MakeFile| file.
%
% \subsection{Configuration of the options}\label{subsec:confopt}
%
% Most of the options can be passed directly to the package or using the
% command |\setupsc|. All boolean keys can be passed using the
% equal sign `|=|' or just the
% name of the key, all unknown \mymeta{keys} will return an error. In this section
% are described some of the options, a summary of all options is shown in \S\ref{subsec:optover}.
%
% \begin{function}{\setupsc}
%   \begin{syntax}
%     \cmdexamp{setupsc}{key \textnormal{\textcolor{gray}{=}} val}
%   \end{syntax}
%
% The command \ics*{setupsc} takes the mandatory argument
% \mymarg{key \textnormal{\textcolor{gray}{=}} val} and sets the \mymeta{keys} for the rest of the
% document, or until the end of the current group, it can be used both in
% the preamble and in the body of the document as many times as desired.
% However, options set in the declaration of an environment (with
% |\newenvsc|) have precedence over options set with |\setupsc|.
%
% Options in the optional arguments of environments and
% commands have the highest precedence, overriding both
% options in |\newenvsc| and in |\setupsc|.
% \end{function}
%
% \keyexampcmd{debug-var}{true \textnormal{\textcolor{lightgray}{\textbar}} false}{true}[setupsc]
% Determines whether the \mymeta{argument} passed to commands or the \mymeta{body} passed
% to provided environments is written to the \texttt{.log} file. This \mymeta{key}
% is only available as a package option or using |\setupsc|.
%
% \keyexampcmd{verb-font}{font family}{\textnormal{\ttfamily\textbackslash{}ttfamily}}[setupsc]
% Sets the \mymeta{font family} used to display the \mymeta{stored content} for
% |\typestored|, |\mergesc| and |\meaningsc| commands. This \mymeta{key}
% is only available as a package option or using |\setupsc|.
%
% \keyexampcmd{store-all}{seq name}{not used}[setupsc]
% It is a \mymeta{meta-key} that sets the \mykey{store-env} key of the \myenv*[no-index]{scontents}
% environment and the \mykey{store-cmd} key of the |\Scontents| command. This \mymeta{key}
% is only available as a package option or using |\setupsc|.
%
% \keyexampcmd{remember}{seq names}{not used}[setupsc]
% Sets the \emph{sequences}, a comma separated list of \mymarg{seq names},
% whose \mymeta{stored contents} can be used before they are stored, as
% |\label| and |\ref| do with the references. At the end of the document
% the \mymeta{stored contents} of these \emph{sequences} are written to the
% file |\jobname.sct| and in the next compilation |\getstored|,
% |\foreachsc|, |\typestored|, |\meaningsc|, |\mergesc| and |\countsc|
% take the \mymeta{stored contents} from it, so they are available before
% they are stored.
% As with the references, two compilations are needed: the first one prints
% nothing where a \mymeta{stored content} is not available yet and a
% \enquote{warning} at the end of the document asks to compile again. If
% a \mymeta{stored content} is still not available, for example with an
% \mymeta{index} greater than the number of \mymeta{stored contents}, a
% \enquote{warning} says that there were undefined \mymeta{stored contents}.
% This \mymeta{key} is only available in \hologo{LaTeX}, in the preamble,
% as a package option or using |\setupsc|. For example:
% \iffalse
%<*example>
% \fi
\begin{examplecode}[frame=single]
\setupsc{remember=objectives} % in the preamble
\section{Objectives}
\getstored[1]{objectives}
\section{Methods}
\Scontents[store-cmd=objectives]{Measure the effect of the method.}
\end{examplecode}
% \iffalse
%</example>
% \fi
% A complete example is in \S\ref{exa:remember}. The file |\jobname.sct| is
% an auxiliary file, as the |.aux| file, and it can be removed at any time.
% To remove it with |latexmk -c| add this line to the \myfile{latexmkrc}
% file:
% \iffalse
%<*example>
% \fi
\begin{examplecode}[frame=single]
push @generated_exts, 'sct';
\end{examplecode}
% \iffalse
%</example>
% \fi
%
% \keyexampcmd{overwrite}{true \textnormal{\textcolor{lightgray}{\textbar}} false}{false}[setupsc]
% Sets whether the \mymeta{files} generated by \mykey{write-out} and \mykey{write-env}
% from the \myenv*[no-index]{scontents} environment will be rewritten. This \mymeta{key} is available as
% a package option, for |\setupsc|, for |\Scontents| and
% |\Scontents*|, for the base environment \myenv*[no-index]{scontents} and all
% environments created using |\newenvsc|.
%
% \keyexampcmd{print-all}{true \textnormal{\textcolor{lightgray}{\textbar}} false}{false}[setupsc]
% It is a \mymeta{meta-key} that sets the \mykey{print-env} key of the \myenv*[no-index]{scontents}
% environment and the \mykey{print-cmd} key of the |\Scontents| command. This \mymeta{key} is
% only available as a package option or using |\setupsc|.
%
% \keyexampcmd{force-eol}{true \textnormal{\textcolor{lightgray}{\textbar}} false}{false}[setupsc]
% Sets if the \emph{last end of line} for the \mymeta{stored content} is hidden or not.
% This \mymeta{key} is necessary only if the \emph{last line} is the closing of some
% environment defined by \mypkg{fancyvrb}\cite{fancyvrb} or \mypkg{fvextra}\cite{fvextra}
% packages as |\end{Verbatim}| or another environment that does not support
% a comments `|%|' after closing |\end{<env>}%|.
% This \mymeta{key} is available for the base environment \myenv*[no-index]{scontents},
% the |\Scontents| and |\Scontents*| commands and all environments
% created using |\newenvsc|.
%
% \keyexampcmd{width-tab}{integer}{1}[setupsc]
% Sets the equivalence in \mymeta{spaces} for the character \texttt{TAB} `\LKeyTab'
% used when displaying \mymeta{stored content} in \emph{verbatim style}. The value
% must be a \mymeta{positive integer}. This \mymeta{key} is available for |\typestored|,
% |\mergesc| and |\meaningsc| commands.
%
% \subsection{Options Overview}\label{subsec:optover}
%
% \newcommand*{\xmark}{\textcolor{OrangeRed}{✘}}%
% \newcommand*{\cmark}{\textcolor{newlinkcolor}{✔}}%
%
% \setlength{\tabcolsep}{0.25em}
% \begin{center}
% \small
% \begin{tabular}{lcccccccc}
% \toprule
% \texttt{key} & \texttt{package} &|\setupsc| &\myenv*[no-index]{scontents} &|\Scontents| &|\Scontents*| &|\typestored| &|\meaningsc| &|\mergesc|\\
% \midrule
%  \mykey{debug-var}  & \cmark  & \cmark  &  \xmark  & \xmark  & \xmark  & \xmark  & \xmark & \xmark \\
%  \mykey{verb-font}  & \cmark  & \cmark  &  \xmark  & \xmark  & \xmark  & \xmark  & \xmark & \xmark \\
%  \mykey{store-all}  & \cmark  & \cmark  &  \xmark  & \xmark  & \xmark  & \xmark  & \xmark & \xmark \\
%  \mykey{remember}   & \cmark  & \cmark  &  \xmark  & \xmark  & \xmark  & \xmark  & \xmark & \xmark \\
%  \mykey{overwrite}  & \cmark  & \cmark  &  \cmark  & \cmark  & \cmark  & \cmark  & \cmark & \cmark \\
%  \mykey{print-all}  & \cmark  & \cmark  &  \xmark  & \xmark  & \xmark  & \xmark  & \xmark & \xmark \\
%  \mykey{force-eol}  & \cmark  & \cmark  &  \cmark  & \cmark  & \cmark  & \xmark  & \xmark & \xmark \\
%  \mykey{width-tab}  & \cmark  & \cmark  &  \xmark  & \xmark  & \xmark  & \cmark  & \cmark & \cmark \\
%  \mykey{store-env}  & \cmark  & \cmark  &  \cmark  & \xmark  & \xmark  & \xmark  & \xmark & \xmark \\
%  \mykey{store-cmd}  & \cmark  & \cmark  &  \xmark  & \cmark  & \cmark  & \xmark  & \xmark & \xmark \\
%  \mykey{print-env}  & \cmark  & \cmark  &  \cmark  & \xmark  & \xmark  & \xmark  & \xmark & \xmark \\
%  \mykey{print-cmd}  & \cmark  & \cmark  &  \xmark  & \cmark  & \cmark  & \cmark  & \cmark & \cmark \\
%  \mykey{write-env}  & \xmark  & \xmark  &  \cmark  & \xmark  & \xmark  & \xmark  & \xmark & \xmark \\
%  \mykey{write-cmd}  & \xmark  & \xmark  &  \xmark  & \cmark  & \cmark  & \xmark  & \xmark & \xmark \\
%  \mykey{write-out}  & \xmark  & \xmark  &  \cmark  & \cmark  & \cmark  & \cmark  & \cmark & \cmark \\
%  \mykey{typestored} & \xmark  & \xmark  &  \xmark  & \xmark  & \xmark  & \xmark  & \xmark & \cmark \\
%  \mykey{meaningsc}  & \xmark  & \xmark  &  \xmark  & \xmark  & \xmark  & \xmark  & \xmark & \cmark \\
%  \mykey{getstored}  & \xmark  & \xmark  &  \xmark  & \xmark  & \xmark  & \xmark  & \xmark & \cmark \\
% \bottomrule
% \end{tabular}
% \end{center}
%
% \section{User interface}\label{sec:interface}
%
% The user interface consists in \myenv*[no-index]{scontents} environment, |\Scontents|
% and |\Scontents*| commands to \mymeta{stored content}, |\getstored|
% command to get the \mymeta{stored content}, |\typestored| and |\mergesc| commands to print
% \emph{verbatim style} the \mymeta{stored content} along with other utilities described
% in this documentation.
%
% \subsection{The environment \texttt{scontents}}\label{subsec:envscontents}
%
% \begin{function}[label=SCONTENTS]{scontents}
%   \begin{syntax}
%   \envexamp{scontents}
%   \end{syntax}
%
% The \myenv*{scontents} environment takes the optional argument
% \myoarg{key \textnormal{\textcolor{gray}{=}} val} and the \mymarg{body env}, which it
% \emph{\enquote{stores}} in a \mymeta{sequence} or \emph{\enquote{writes}}
% to an \mymeta{external file} if desired, including \emph{verbatim
% material}. After the package has been loaded, the environment can be
% used both in the preamble and in the body of the document.
%
% For the correct operation |\begin{scontents}| and |\end{scontents}| must
% be in \emph{different lines}, all \mymeta{keys} must be passed separated by
% commas and \emph{without spaces} `\verb*+ +' of the start of the
% environment.
% \end{function}
%
% Comments `|%|' or \emph{any character} after
% |\begin{scontents}| or \myoarg{key \textnormal{\textcolor{gray}{=}} val} on
% the \emph{same line} are NOT supported, the package will return an \enquote{error} message if this happens.
% In a similar way comments `|%|' or \emph{any character}
% after |\end{scontents}| on the \emph{same line} the package will return a \enquote{warning} message.
%
% The environment can be \emph{\enquote{nested}} if it is properly balanced and
% does not appear \emph{\enquote{literally}} in commented lines or in some \emph{verbatim}
% environment or command. As an example:
%
% \iffalse
%<*example>
% \fi
\begin{examplecode}[frame=single]
\begin{scontents}[store-env=outer]
This text is in the outer environment (before nested).
\begin{scontents}[store-env=inner]
This text is found in the inner environment (inside of nested).
\end{scontents}
This text is in the outer environment (after nested).
\end{scontents}
\end{examplecode}
% \iffalse
%</example>
% \fi
%
% Of course, the \mymeta{stored content} in the \emph{sequence} \mymarg{inner}
% is \emph{only available} after \mymeta{stored content} in the \emph{sequence}
% \mymarg{outer}  one has been retrieved, either by using the key \mykey{print-env}
% or |\getstored| command.
%
% \begin{important}*
% It is advisable to store the \mymeta{content} in \emph{sequences} with
% different names, so as not to get lost in the order (position) in which
% it is stored.
% \end{important}
%
% \subsection*{Notes for \hologo{plainTeX} and \hologo{ConTeXt} users}
%
% In \hologo{plainTeX} there are no environments as in \hologo{LaTeX}.
% Instead of using the environment \myenv*[no-index]{scontents}, one should use a
% \emph{\enquote{pseudo environment}} delimited by |\scontents| and |\endscontents|.
%
% \begin{function}{\scontents,\endscontents}
%   \begin{syntax}
%   \envexaplain{scontents}
%   \end{syntax}
%   The \emph{pseudo environment} takes the same optional argument
%   \myoarg{key \textnormal{\textcolor{gray}{=}} val} as the \myenv*[no-index]{scontents}
%   environment, on the same line as |\scontents|, and the
%   \mymarg{body env} up to |\endscontents|.
% \end{function}
%
% \hologo{ConTeXt} users should use |\startscontents| and |\stopscontents|.
% \begin{function}{\startscontents,\stopscontents}
%   \begin{syntax}
%   \envexaplain[start]{scontents}[stop]
%   \end{syntax}
%   The \emph{pseudo environment} takes the same optional argument
%   \myoarg{key \textnormal{\textcolor{gray}{=}} val} as the \myenv*[no-index]{scontents}
%   environment, on the same line as |\startscontents|, and the
%   \mymarg{body env} up to |\stopscontents|.
% \end{function}
%
% \subsection*{Options for environment}
%
% The environment options can be configured globally using option
% in package or the |\setupsc| command and locally using
% \myoarg{key \textnormal{\textcolor{gray}{=}} val} in the environment.
% The key \mykey{force-eol} is available for this environment.
%
% \keyexampcmd{store-env}{seq name}{contents}[env]
% Sets the \emph{name} of the \emph{sequence} in which the \mymarg{body env} will be
% stored. If the \emph{sequence} does not exist, it will be created globally.
%
% \keyexampcmd{print-env}{true \textnormal{\textcolor{lightgray}{\textbar}} false}{false}[env]
% Sets if the \mymeta{stored content} is displayed or not at the time of
% running the environment. The \mymeta{stored content} is extracted from
% the \emph{sequence} \mymarg{seq name} set by the key \mykey{store-env}
% at the time it is executed.
%
% \keyexampcmd{write-env}{file.ext}{not used}[env]
% Sets the \emph{name} of the \mymeta{external file} in which the \mymarg{body env} of
% the environment will be written. The \mymeta{file.ext} will be created
% in the working directory and the \mymarg{body env} will be \emph{stored}
% in the \emph{sequence} set by the key \mykey{store-env}
% at the time it is executed. If \mymeta{file.ext} does not exist, it will
% be created or overwritten if the \mykey{overwrite} key is used.
%
% \keyexampcmd{write-out}{file.ext}{not used}[env]
% Sets the \emph{name} of the \mymeta{external file} in which the \mymarg{body env} of
% the environment will be written. The \mymeta{file.ext} will be created
% in the working directory and the \mymarg{body env} will NOT be \emph{stored}
% in the \emph{sequence} set by the key \mykey{store-env}
% at the time it is executed. If \mymeta{file.ext} does not exist, it will
% be created or overwritten if the \mykey{overwrite} key is used.
%
% \begin{important}*
% In the keys \mykey{write-env} and \mykey{write-out} the character
% \texttt{TAB} will be written in \mymeta{file.ext},
% relative or absolute paths are not supported. \hologo{XeLaTeX} users
% using character \texttt{TAB} must add |-8bit|
% at the command line, otherwise you will get \hologo{TeX} character
% \texttt{TAB} `\myhlc|^^I|' in \mymeta{file.ext}.
% \end{important}
%
% \subsection{The command \cs{newenvsc}}\label{subsec:newenvsc}
%
% \newsavebox{\exaboxtmp}
% \begin{lrbox}{\exaboxtmp}
%    \small\ttfamily
%    \textcolor{module_name}{\textbackslash newenvsc}\mymarg{env name}\myoarg{initial keys}
% \end{lrbox}
%
% \begin{function}{\newenvsc}
%   \begin{syntax}
%    \usebox{\exaboxtmp}
%   \end{syntax}
% The command \ics*{newenvsc} takes the mandatory argument
% \mymarg{env name} and the optional argument \myoarg{initial keys}, and
% creates the \mymeta{new environment} \mymarg{env name} with the same
% characteristics of the \myenv*[no-index]{scontents} environment. The
% values entered in \myoarg{initial keys} will be considered as the
% default values for this new environment and the valid \mymeta{keys} are
% \mykey{store-env} and \mykey{print-env}. If \mymarg{env name} already
% exists, an \enquote{error} is returned and its definition is not altered.
% \end{function}
%
% In \hologo{plainTeX} and \hologo{ConTeXt} the \mymeta{new environment}
% is a \emph{pseudo environment} as the one of \myenv*[no-index]{scontents}
% (\S\ref{subsec:envscontents}): for an environment named |myenv| it is
% |\myenv|\,\dots\,|\endmyenv| in \hologo{plainTeX} and
% |\startmyenv|\,\dots\,|\stopmyenv| in \hologo{ConTeXt}. For example:
%
% \iffalse
%<*example>
% \fi
\begin{examplecode}[frame=single]
\newenvsc{myenvstore}[store-env=myseq,print-env=false]
\end{examplecode}
% \iffalse
%</example>
% \fi
%
% created the environment |myenvstore| that \mymeta{stored content} in
% the \emph{sequence} \mymarg{myseq} and will NOT display the \mymeta{stored content}
% when the environment it is executed.
%
% \subsection{The command \cs{Scontents}}\label{subsec:Scontents}
%
% \begin{function}{\Scontents}
%   \begin{syntax}
%     \cmdexamp{Scontents}[key \textnormal{\textcolor{gray}{=}} val]{argument}
%     \cmdexamp[*]{Scontents}[key \textnormal{\textcolor{gray}{=}} val]{argument}
%     \cmdexamp[*]{Scontents}[key \textnormal{\textcolor{gray}{=}} val]{argument}[del]
%   \end{syntax}
% The command \ics*{Scontents} takes an optional \emph{starred argument}
% `|*|', the optional argument \myoarg{key \textnormal{\textcolor{gray}{=}} val} and the mandatory
% \mymarg{argument}, between \emph{braces} or, in the starred version,
% between two \mymeta[cf=star]{del}, and stores the \mymarg{argument} in
% the \emph{sequence} set by the key \mykey{store-cmd}.
% \end{function}
%
% The command |\Scontents| reads the \mymarg{argument} in standard
% mode and \emph{\enquote{stores}} it in the \emph{sequence} set
% by the key \mykey{store-cmd} at the time it is executed. It is not
% possible to pass \emph{verbatim things}, but it is possible to use
% the implementation of |\Verb| delimited by \emph{braces}
% `|{ }|'
% provided by the \mypkg{fvextra}\cite{fvextra} package for \emph{verbatim one line}
% and |\lstinline| from \mypkg{listings}\cite{listings} package, but it
% is preferable to use the \emph{starred argument} `|*|'.
%
% The |\Scontents*| command reads the \mymarg{argument} under \emph{verbatim catcode}
% regimen and \emph{\enquote{stores}} it in the \emph{sequence} set
% by the key \mykey{store-cmd} at the time it is executed. If its \emph{\enquote{first}}
% delimiter is a \emph{brace} `|{|', it will be
% assumed that the \mymarg{argument} is nested within \emph{braces}. Otherwise it
% will be assumed that \mymarg{argument} is delimited by that
% first delimiter \mymeta[cf=star]{del} like command |\verb|.
% Blank lines are preserved, escaped braces `|\{|' and
% `|\}|' must also be
% balanced if the \mymarg{argument} is used with \emph{braces} and character \texttt{TAB} typed
% from the keyboard are converted into spaces.
%
% The \emph{starred argument} `|*|' and \myoarg{key \textnormal{\textcolor{gray}{=}} val}
% must NOT be separated by \emph{spaces} `\verb*+ +' between them and the command.
% Both versions can be used anywhere in the document and cannot be used
% as an \mymarg{argument} for other command.
%
% \subsection*{Options for command}
%
% The command options can be configured globally using option in package
% or the |\setupsc| command and locally using \myoarg{key \textnormal{\textcolor{gray}{=}} val}.
%
% \keyexampcmd{store-cmd}{seq name}{contents}[Scontents]
% Sets the \emph{name} of the \emph{sequence} in which the \mymarg{argument}
% is stored. If the \emph{sequence} does not exist, it will be created globally.
%
% \keyexampcmd{print-cmd}{true \textnormal{\textcolor{lightgray}{\textbar}} false}{false}[Scontents]
% Sets if the \mymeta{stored content} is displayed or not at the time of
% running the command. The \mymeta{stored content} is extracted from the \emph{sequence}
% \mymarg{seq name} set by the key \mykey{store-cmd} at the time it is executed.
%
% \subsection*{Options for writing files}
%
% The following \mymeta{keys} and the \mykey{force-eol} and \mykey{overwrite}
% keys are available for both versions of the command. The |\Scontents*|
% command writes the \mymarg{argument} to \mymeta{file.ext} exactly as it was
% typed. The |\Scontents| command reads the \mymarg{argument} in standard
% mode, so it is written as a list of tokens, in the same way as |\detokenize|
% does: a space is added after each control word, the character `|#|' is
% doubled, the line breaks become spaces and the blank lines become |\par|.
% To write the \mymarg{argument} literally, use the \emph{starred argument}
% `|*|'.
%
% \keyexampcmd{write-cmd}{file.ext}{not used}[Scontents]
% Sets the \emph{name} of the \mymeta{external file} in which the \mymarg{argument}
% will be written. The \mymeta{file.ext} will be created in the working
% directory and the \mymarg{argument} will be \emph{stored}
% in the \emph{sequence} set by the key \mykey{store-cmd}
% at the time it is executed. If \mymeta{file.ext} does not exist, it will
% be created or overwritten if the \mykey{overwrite} key is used.
%
% \keyexampcmd{write-out}{file.ext}{not used}[Scontents]
% Sets the \emph{name} of the \mymeta{external file} in which the \mymarg{argument}
% will be written. The \mymeta{file.ext} will be created in the working
% directory and the \mymarg{argument} will NOT be \emph{stored}
% in any \emph{sequence} set by the key \mykey{store-cmd}
% at the time it is executed. If \mymeta{file.ext} does not exist, it will
% be created or overwritten if the \mykey{overwrite} key is used.
%
% \begin{important}*
% In the keys \mykey{write-cmd} and \mykey{write-out} the character
% \texttt{TAB} will be written in \mymeta{file.ext}, relative or absolute
% paths are not supported. \hologo{XeLaTeX} users using character \texttt{TAB}
% must add |-8bit| at the command line, otherwise
% you will get \hologo{TeX} character \texttt{TAB} `\myhlc|^^I|' in \mymeta{file.ext}.
% \end{important}
%
% \subsection{The command \cs{getstored}}\label{subsec:getstored}
%
% \begin{function}{\getstored}
%   \begin{syntax}
%      \cmdexamp{getstored}[index]{seq name}
%   \end{syntax}
% The command \ics*{getstored} takes the optional argument
% \myoarg{index} and the mandatory argument \mymarg{seq name}, and
% retrieves the \mymeta{stored content} whose \emph{position} in the
% \emph{sequence} \mymarg{seq name} is the \emph{integer value} set in
% \mymeta{index}. A \emph{negative} \mymeta{index} counts from the last
% \mymeta{stored content} and, if the \emph{optional argument} is not
% passed, the \emph{\enquote{last}} \mymeta{stored content} is retrieved.
% \end{function}
%
% The command is robust and can be used as an \mymarg{argument} for
% another command.
%
% \subsection{The command \cs{foreachsc}}\label{subsec:foreachsc}
%
% \begin{function}{\foreachsc}
%   \begin{syntax}
%     \cmdexamp{foreachsc}[key \textnormal{\textcolor{gray}{=}} val]{seq name}
%   \end{syntax}
% The command \ics*{foreachsc} takes the optional argument
% \myoarg{key \textnormal{\textcolor{gray}{=}} val} and the mandatory argument \mymarg{seq name},
% and executes the command |\getstored| on each \mymeta{stored content}
% in the \emph{sequence} \mymarg{seq name}, or |\typestored| or
% |\meaningsc| with the \mykey{typestored} or \mykey{meaningsc} key. If the
% \emph{optional argument} is not passed, |\getstored| is executed on all
% the \mymeta{stored content} in the \emph{sequence} \mymarg{seq name}.
% \end{function}
%
% \subsubsection*{Options for command}
%
% \keyexampcmd*{getstored}{without value}{active}[foreachsc]
% Executes |\getstored| on each \mymeta{stored content}, as without
% \mymeta{keys}.
%
% \keyexampcmd*{typestored}{without value}{not active}[foreachsc]
% Executes |\typestored| on each \mymeta{stored content}, which is shown in
% \emph{verbatim style} (\S\ref{subsec:typestored}).
%
% \keyexampcmd*{meaningsc}{without value}{not active}[foreachsc]
% Executes |\meaningsc| on each \mymeta{stored content}
% (\S\ref{subsec:meaningsc}).
%
% \keyexampcmd{sep}{code}{empty}[foreachsc]
% Establishes the \emph{separation} between each \mymeta{stored content}
% in the \emph{sequence} \mymarg{seq name}.
% For example, you can use |sep={\\[10pt]}| for vertical separation of
% \mymeta{stored contents}.
%
% \keyexampcmd{step}{integer}{1}[foreachsc]
% Sets the \emph{increment} (\mymeta{step}) applied to the value set by key \mykey{start}
% for each \mymeta{stored content} in the \emph{sequence} \mymarg{seq name}.
% The value must be a \mymeta{positive integer}.
%
% \keyexampcmd{start}{integer}{1}[foreachsc]
% Set the \emph{position} of the \mymeta{stored content} within the
% \emph{sequence} \mymarg{seq name} from which to \emph{start} executing.
% The value must be a \mymeta{positive integer}.
%
% \keyexampcmd{stop}{integer}{total}[foreachsc]
% Set the \emph{position} of the \mymeta{stored content} within the
% \emph{sequence} \mymarg{seq name} at which execution ends. The value
% must be a \mymeta{positive integer}.
%
% \keyexampcmd{before}{code}{empty}[foreachsc]
% Sets the \mymarg{code} that will be executed \emph{before} each \mymeta{stored content}
% within the \emph{sequence} \mymarg{seq name}. The \mymarg{code} must
% be passed \emph{between braces} `|{ }|'.
%
% \keyexampcmd{after}{code}{empty}[foreachsc]
% Sets the \mymarg{code} that will be executed \emph{after} each \mymeta{stored content}
% within the \emph{sequence} \mymarg{seq name}. The \mymarg{code} must
% be passed \emph{between braces} `|{ }|'.
%
% \newsavebox{\hashbox}
% \begin{lrbox}{\hashbox}
% \lstinline[language=scontents-doc,basicstyle=\small\ttfamily]+{#1}+
% \end{lrbox}
%
% \keyexampcmd{wrapper}{code{} \space\usebox{\hashbox} more code}{empty}[foreachsc]
% Wraps the \mymeta{stored content} within the \emph{sequence} \mymarg{seq name}
% referenced by |{#1}|. The \mymarg{code} must be passed \emph{between braces}
% `|{ }|'.
% For example |\foreachsc[wrapper={\makebox[1em][l]{#1}}]{contents}|.
%
% \subsection{The command \cs{typestored}}\label{subsec:typestored}
%
% \begin{function}{\typestored}
%   \begin{syntax}
%     \cmdexamp{typestored}[index\textnormal{\textcolor{gray}{,}} start-stop\textnormal{\textcolor{gray}{,}} 1-end\textnormal{\textcolor{gray}{,}} keys]{seq name}
%   \end{syntax}
% The command \ics*{typestored} takes the optional argument with the
% \mymeta{index}, the \mymeta{start-stop}, the \mymeta{1-end} and the
% \mymeta{keys}, and the mandatory argument \mymarg{seq name}, and prints
% the \mymeta{stored content} in the \emph{sequence} \mymarg{seq name}
% in the internal \myenv*[no-index]{verbatimsc} environment
% (\S\ref{subsec:verbatimsc}). If the \emph{optional argument} is not
% passed, the \emph{first} \mymeta{stored content} is printed.
% \end{function}
%
% The \emph{integer value} set in \mymeta{index} is the \emph{position}
% of the \mymeta{stored content} in the \emph{sequence} \mymarg{seq name},
% a \emph{negative} \mymeta{index} counts from the last
% \mymeta{stored content} as in |\getstored|. The \emph{integer values}
% set in \mymeta{start-stop} define a \emph{range} of positions, where
% |end| is the last \mymeta{stored content} and a \mymeta{start} greater
% than \mymeta{stop} prints the \emph{range} in reverse order, and
% \mymeta{1-end} prints \emph{\enquote{all}} the \mymeta{stored content}.
% Several of them can be given separated by commas. The rest of the
% accepted \mymeta{keys} are \mykey{print-cmd} with default value |true|,
% \mykey{write-out}, \mykey{width-tab} and \mykey{overwrite}.
%
% \begin{important}*
% In the key \mykey{write-out} the character \texttt{TAB} will be written
% in \mymeta{file.ext}, relative or absolute paths are not supported.
% \hologo{XeLaTeX} users using character \texttt{TAB} must add |-8bit|
% at the command line, otherwise you will get \hologo{TeX} character
% \texttt{TAB} `\myhlc|^^I|' in \mymeta{file.ext}.
% \end{important}
%
% \subsection{The command \cs{meaningsc}}\label{subsec:meaningsc}
%
% \begin{function}{\meaningsc}
%   \begin{syntax}
%     \cmdexamp{meaningsc}[index\textnormal{\textcolor{gray}{,}} start-stop\textnormal{\textcolor{gray}{,}} 1-end\textnormal{\textcolor{gray}{,}} keys]{seq name}
%   \end{syntax}
% The command \ics*{meaningsc} takes the same optional argument as
% |\typestored| (\S\ref{subsec:typestored}) and the mandatory argument
% \mymarg{seq name}, and prints the \emph{meaning} of the
% \mymeta{stored content} in the \emph{sequence} \mymarg{seq name}, as
% |\meaning| does, on a single line. The \mymeta{index},
% \mymeta{start-stop}, \mymeta{1-end} and \mymeta{keys} have the same
% behavior as in |\typestored| and, if the \emph{optional argument} is
% not passed, the \emph{first} \mymeta{stored content} is printed.
% \end{function}
%
% \subsection{The command \cs{mergesc}}\label{subsec:mergesc}
%
% \newsavebox{\argmergesc}
% \begin{lrbox}{\argmergesc}
% \small\mymarg{seq A}\myoarg{index}\textcolor{gray}{, }\mymarg{seq B}\myoarg{start \textcolor{gray}{-} stop}\textcolor{gray}{, }\mymarg{seq C}\myoarg{1-end}
% \end{lrbox}
%
% \begin{function}{\mergesc}
%   \begin{syntax}
%      \cmdexamp{mergesc}[typestored \textnormal{\textcolor{lightgray}{\textbar}} meaningsc \textnormal{\textcolor{lightgray}{\textbar}} getstored\textcolor{lightgray}{, }keys]{\usebox{\argmergesc}}
%   \end{syntax}
% The command \ics*{mergesc} takes the optional argument with the
% \mymeta{keys}, one of them \mykey{typestored}, \mykey{meaningsc} or
% \mykey{getstored}, and the mandatory argument with a
% \emph{comma separated list} of \emph{sequences}, and assembles the
% \mymeta{stored content} in them, as \mymarg{seq A}|[1]|,
% \mymarg{seq B}|[2-5]| and \mymarg{seq C}|[1-|\mykey{end}|]| in the
% syntax, and then executes |\typestored| (\S\ref{subsec:typestored}) if
% the \mykey{typestored} key is active, |\meaningsc|
% (\S\ref{subsec:meaningsc}) if the \mykey{meaningsc} key is active, or
% rescans it as |\getstored| (\S\ref{subsec:getstored}) does if the
% \mykey{getstored} key is active.
% \end{function}
%
% The \mymarg{argument} taken by this command is a \emph{comma separated list}
% of the form \mymarg{seq name} followed by either \myoarg{index},
% \myoarg{start-stop} or \myoarg{1-end}, a \mymarg{seq name} alone
% assembles all its \mymeta{stored content}.
% The use of the keys \mykey{typestored}, \mykey{meaningsc} or
% \mykey{getstored} are \emph{\enquote{mandatory}} and disjoint from each
% other, the rest of the accepted \mymeta{keys} are \mykey{print-cmd},
% \mykey{write-out}, \mykey{width-tab} and \mykey{overwrite}, which are not
% accepted with the \mykey{getstored} key.
%
% The use of the \mykey{write-out} key with this command follows the same
% rules already described, the main advantage is that allows joining
% \mymeta{stored content} \emph{without rewriting} the file over and over again,
% by design \hologo{TeX} does not have an \emph{append mode} for writing
% files, this effectively allows you to write chunks of code and then
% merge them into a single file.
%
% \subsection{The environment \env{verbatimsc}}\label{subsec:verbatimsc}
%
% \begin{function}{verbatimsc}
% The environment used by |\typestored| and |\mergesc| to
% display the \mymeta{stored content} in \emph{verbatim style}.
% The environment is compatible with \emph{tagged} \texttt{PDF} and can
% be customized in the following ways after loading the \mypkg*[no-index]{scontents}
% package:
% \end{function}
%
% Using the packages \mypkg{fvextra}\cite{fvextra} or \mypkg{fancyvrb}\cite{fancyvrb}:
% \iffalse
%<*example>
% \fi
\begin{examplecode}[frame=single]
\ExplSyntaxOn
\cs_undefine:N \verbatimsc
\cs_undefine:N \endverbatimsc
\ExplSyntaxOff
\usepackage{fancyvrb}
\DefineVerbatimEnvironment{verbatimsc}{Verbatim}{numbers=left}
\end{examplecode}
% \iffalse
%</example>
% \fi
% Using the package \mypkg{minted}\cite{minted}:
% \iffalse
%<*example>
% \fi
\begin{examplecode}[frame=single]
\ExplSyntaxOn
\cs_undefine:N \verbatimsc
\cs_undefine:N \endverbatimsc
\ExplSyntaxOff
\usepackage{minted}
\newminted{tex}{linenos}
\newenvironment{verbatimsc}{\VerbatimEnvironment\begin{texcode}}{\end{texcode}}
\end{examplecode}
% \iffalse
%</example>
% \fi
% Using the package \mypkg{listings}\cite{listings}:
% \iffalse
%<*example>
% \fi
\begin{examplecode}[frame=single]
\ExplSyntaxOn
\cs_undefine:N \verbatimsc
\cs_undefine:N \endverbatimsc
\ExplSyntaxOff
\usepackage{listings}
\lstnewenvironment{verbatimsc}
  {
   \lstset{
           basicstyle=\small\ttfamily,
           columns=fullflexible,
           language=[LaTeX]TeX,
           numbers=left,
           numberstyle=\tiny\color{gray},
           keywordstyle=\color{red}
          }
  }{}
\end{examplecode}
% \iffalse
%</example>
% \fi
%
% \begin{function}{\startverbatimsc, \stopverbatimsc}
% In \hologo{plainTeX} the environment is |\verbatimsc|\,\dots\,|\endverbatimsc|
% and in \hologo{ConTeXt} it is |\startverbatimsc|\,\dots\,|\stopverbatimsc|,
% defined with |\definetyping|, so there it can be customized with
% |\setuptyping[verbatimsc][...]|.
% \end{function}
%
% \begin{important}*
% At the moment, the \mypkg{fvextra}\cite{fvextra} and \mypkg{fancyvrb}\cite{fancyvrb}
% packages partially support \emph{tagged} \texttt{PDF}.
% \end{important}
%
% \section{Other commands provided}
%
% \subsection{The command \cs{countsc}}\label{subsec:countsc}
%
% \begin{function}{\countsc}
%   \begin{syntax}
%      \cmdexamp{countsc}{seq name}
%   \end{syntax}
% The command \ics*{countsc} takes the mandatory argument
% \mymarg{seq name} and returns the number of \mymeta{stored content} in
% the \emph{sequence} \mymarg{seq name}. The command is expandable, so it
% can be used in an \emph{integer expression}, and if the \emph{sequence}
% does not exist an \enquote{error} is returned along with |0|.
% \end{function}
%
% \subsection{The command \cs{cleanseqsc}}\label{subsec:cleanseqsc}
%
% \begin{function}{\cleanseqsc}
%   \begin{syntax}
%      \cmdexamp{cleanseqsc}{seq name}
%   \end{syntax}
% The command \ics*{cleanseqsc} takes the mandatory argument
% \mymarg{seq name} and removes all \mymeta{stored content} in the
% \emph{sequence} \mymarg{seq name}. If the \emph{sequence} does not
% exist, it is created empty.
% \end{function}
%
% \section{Programming interface}\label{sec:api}
%
% For other packages and for the code written with \mypkg{expl3}, the
% \mymeta{stored contents} can be read without printing them with the
% following functions. They work in \hologo{LaTeX}, \hologo{plainTeX} and
% \hologo{ConTeXt} and also read the \emph{sequences} set by the
% \mykey{remember} key.
%
% The \mymeta{stored contents} are given as they were stored, without the
% mark that \mypkg*[no-index]{scontents} adds to hide the last end of line:
% the content of an environment is a string whose lines are separated by
% the end of line character \myhlc|^^J|, the content of |\Scontents*| is also a
% string and the content of |\Scontents| keeps its tokens.
%
% \begin{function}[EXP,pTF]{\scontents_if_exist:n}
%   \begin{syntax}
%     \myhlc|\scontents_if_exist_p:n| \mymarg{seq name}
%     \myhlc|\scontents_if_exist:nTF| \mymarg{seq name} \mymarg{true code} \mymarg{false code}
%   \end{syntax}
% Tests if the \emph{sequence} \mymarg{seq name} exists.
% \end{function}
%
% \begin{function}[EXP]{\scontents_count:n}
%   \begin{syntax}
%     \myhlc|\scontents_count:n| \mymarg{seq name}
%   \end{syntax}
% Leaves the number of \mymeta{stored contents} in the \emph{sequence}
% \mymarg{seq name} in the input stream, or |0| if it does not exist,
% without an \enquote{error}. It can be used in an \emph{integer
% expression}.
% \end{function}
%
% \begin{function}{\scontents_get:nnN}
%   \begin{syntax}
%     \myhlc|\scontents_get:nnN| \mymarg{seq name} \mymarg{index} \mymeta{tl var}
%   \end{syntax}
% Sets the \mymeta{tl var}, locally, to the \mymeta{stored content} at the
% position \mymarg{index} of the \emph{sequence} \mymarg{seq name}. The
% \mymarg{index} is an \emph{integer expression}, a negative one counts
% from the end. If the \emph{sequence} does not exist or the
% \mymarg{index} is out of range, the \mymeta{tl var} is empty and an
% \enquote{error} is returned.
% \end{function}
%
% \begin{function}{\scontents_map_inline:nn}
%   \begin{syntax}
%     \myhlc|\scontents_map_inline:nn| \mymarg{seq name} \mymarg{inline function}
%   \end{syntax}
% Applies the \mymarg{inline function} to each \mymeta{stored content} of
% the \emph{sequence} \mymarg{seq name}, in order, the
% \mymeta{stored content} is |#1|. The \mymarg{inline function} can use
% the other functions and \myhlc|\scontents_map_inline:nn| again. If the
% \emph{sequence} does not exist an \enquote{error} is returned. For
% example, this shows in the \texttt{.log} file each
% \mymeta{stored content} of the \emph{sequence} |data| converted to
% uppercase:
% \iffalse
%<*example>
% \fi
\begin{examplecode}[frame=single]
\ExplSyntaxOn
\scontents_map_inline:nn { data }
  { \iow_log:e { \text_uppercase:n {#1} } }
\ExplSyntaxOff
\end{examplecode}
% \iffalse
%</example>
% \fi
% \end{function}
%
% \section[The \textnormal{\texttt{scontents}} package in action]{The \mypkg*[no-index]{scontents} package in action}
%
% Remember the abstract on the first page? This is it:
%
% \getstored{abstract}
%
% And the description of the package?
%
% \getstored{description}
%
% I've only written:
%
% \typestored{abstract}
%
% and
%
% \typestored{description}
%
% Of course, I didn't copy and paste. The real code they were written with is:
%
% \iffalse
%<*example>
% \fi
\begin{examplecode}[numbers=left]
\begin{scontents}[store-env=abstract,print-env=true]
\begin{abstract}
This package allows to store \hologo{LaTeX} code, including \enquote{\emph{verbatim}},
in \mymeta{sequences} using the \mypkg{l3seq} module of \mypkg{expl3}. The \mymeta{stored
content} can be used as many times as desired in the document, additionally you can write
to \mymeta{external files} or show it in \mymeta{verbatim style}.
\end{abstract}
\end{scontents}
\end{examplecode}
% \iffalse
%</example>
% \fi
%
% and
%
% \iffalse
%<*example>
% \fi
\begin{examplecode}[numbers=left]
\begin{scontents}[store-env=description, print-env=true]
The \mypkg*[no-index]{scontents} package allows to \mymeta{store contents} in \mymeta{sequences}
or \mymeta{external files}. In some ways it is similar to the \mypkg{filecontentsdef}
package, with the difference in which the \mymeta{content} is stored. The idea behind
this package is to get an approach to \hologo{ConTeXt} \emph{\enquote{buffers}} by
making use of \mymeta{sequences}.
\end{scontents}
\end{examplecode}
% \iffalse
%</example>
% \fi
%
% I stored the content in memory and then ran |\getstored| and
% |\typestored|. This is one of the ways you can use \mypkg*[no-index]{scontents}.
%
% \section{Examples}
%
% These are some adapted examples that have served as inspiration for
% the creation of this package. The examples are attached to this documentation
% and can be extracted from your PDF viewer or from the command line by running:
% \iffalse
%<*example>
% \fi
\begin{examplecode}[frame=single]
$ pdfdetach -saveall scontents.pdf
\end{examplecode}
% \iffalse
%</example>
% \fi
% and then you can use the excellent \arara\footnote{The cool \TeX\ automation tool:
% \url{https://www.ctan.org/pkg/arara}} tool to compile them.
%
% \subsection{From \texttt{answers} package}
%
% \subsubsection*{Example 1}
%
% Adaptation of example 1 of the package \mypkg{answers}\cite{answers}.
% \myattachfile*{scontents-exa-1}
% \lstinputlisting[language=scontents-doc,numbers=left]{scontents-exa-1.tex}
%
% \subsection{From \texttt{filecontentsdef} package}
%
% \subsubsection*{Example 2}
%
% Adaptation of example from package \mypkg{filecontentsdef}\cite{filecontentsdef}.
% \myattachfile*{scontents-exa-2}
% \lstinputlisting[language=scontents-doc,numbers=left]{scontents-exa-2.tex}
%
% \subsection{From TeX-SX}
%
% \subsubsection*{Example 3}
%
% Adapted from \href{https://tex.stackexchange.com/q/5338/7832}{LaTeX equivalent of ConTeXt buffers}.
% \myattachfile*{scontents-exa-3}
% \lstinputlisting[language=scontents-doc,numbers=left]{scontents-exa-3.tex}
%
% \subsubsection*{Example 4}
%
% Adapted from \href{https://tex.stackexchange.com/q/184503/7832}{Collecting contents of environment and store them for later retrieval}.
% \myattachfile*{scontents-exa-4}
% \lstinputlisting[language=scontents-doc,numbers=left]{scontents-exa-4.tex}
%
% \subsubsection*{Example 5}
%
% Adapted from \href{https://tex.stackexchange.com/q/373647/7832}{Collect contents of an environment (that contains verbatim content)}.
% \myattachfile*{scontents-exa-5}
% \lstinputlisting[language=scontents-doc,numbers=left]{scontents-exa-5.tex}
%
% \subsubsection*{Example 6}
%
% Adapted from \href{https://tex.stackexchange.com/q/509595/7832}{Environment hiding its content}.
% \myattachfile*{scontents-exa-6}
% \lstinputlisting[language=scontents-doc,numbers=left]{scontents-exa-6.tex}
%
% \subsection{Customization of \texttt{verbatimsc}}
%
% \subsubsection*{Example 7}
%
% Customization of \myenv*[no-index]{verbatimsc} using the \mypkg{fvextra}\cite{fvextra} and
% \mypkg{tcolorbox}\cite{tcolorbox} packages.
% \myattachfile*{scontents-exa-7}
% \lstinputlisting[language=scontents-doc,numbers=left]{scontents-exa-7.tex}
%
% \subsubsection*{Example 8}
%
% Customization of \myenv*[no-index]{verbatimsc} using the \mypkg{listings}\cite{listings} package.
% \myattachfile*{scontents-exa-8}
% \lstinputlisting[language=scontents-doc,numbers=left]{scontents-exa-8.tex}
%
% \subsubsection*{Example 9}
%
% Customization of \myenv*[no-index]{verbatimsc} using the \mypkg{minted}\cite{minted} package.
% \myattachfile*{scontents-exa-9}
% \lstinputlisting[language=scontents-doc,numbers=left]{scontents-exa-9.tex}
%
% \subsection{The command \cs{mergesc} in action}
%
% The command |\mergesc| in action, adapted from Denis Bitouzé request
% at \url{https://github.com/pablgonz/scontents/issues/2}.
% \myattachfile*{scontents-exa-10}
% \lstinputlisting[language=scontents-doc,numbers=left]{scontents-exa-10.tex}
%
% \subsection{Stored contents before storing them}\label{exa:remember}
%
% The \mykey{remember} key in action: the \mymeta{stored contents} of the
% \emph{sequence} |objectives| are used in the section
% \enquote{Objectives} before they are stored in the section
% \enquote{Methods}, as requested at
% \url{https://github.com/pablgonz/scontents/issues/1}. It needs two
% compilations.
% \myattachfile*{scontents-exa-12}
% \lstinputlisting[language=scontents-doc,numbers=left]{scontents-exa-12.tex}
%
% \subsection{The tagged PDF example}
%
% This example is just to show the compatibility of \mypkg*[no-index]{scontents} with
% \emph{tagged} \texttt{PDF} using |lualatex|. The attached files are only
% for testing.
% \myattachfile{scontents-exa-11}
% \lstinputlisting[language=scontents-doc,numbers=left]{scontents-exa-11.tex}
%
% \begin{important}*
% This example has been checked using \href{https://dev.verapdf-rest.duallab.com}{\texttt{veraPDF}}
% together with \href{https://ngpdf.com}{\texttt{ngpdf}}.
% \end{important}
%
% \let\stdsection\section
% \def\section*#1{\stdsection{#1}}
% \expandafter\let\expandafter\thebibliography\csname HDorg@thebibliography\endcsname
%
% \begin{thebibliography}{10}
%
% \bibitem{filecontentsdef} \textsc{Burnol, Jean François}. \enquote{The
% \textsf{filecontentsdef} package}. Available from
% \textsc{ctan}, \url{https://ctan.org/pkg/filecontentsdef}, 2019.
%
% \bibitem{expl3} The \hologo{LaTeX} Project. \enquote{The \textsf{expl3}
% package}. Available from
% \textsc{ctan}, \url{https://www.ctan.org/pkg/expl3}, 2026.
%
% \bibitem{tagpdf} \textsc{Fischer, Ulrike}. \enquote{\textsf{tagpdf} – \hologo{LaTeX}
% kernel code for PDF tagging}. Available from
% \textsc{ctan}, \url{https://www.ctan.org/pkg/tagpdf}, 2026.
%
% \bibitem{fancyvrb} \textsc{Van Zandt, Timothy}. \enquote{The \textsf{fancyvrb}
% package - Fancy Verbatims in \hologo{LaTeX}}. Available from
% \textsc{ctan}, \url{https://www.ctan.org/pkg/fancyvrb}, 2026.
%
% \bibitem{fvextra} \textsc{Poore, Geoffrey M}. \enquote{The \textsf{fvextra}
% package - Extensions and patches for \textsf{fancyvrb}}. Available from
% \textsc{ctan}, \url{https://www.ctan.org/pkg/fvextra}, 2026.
%
% \bibitem{listings} \textsc{Hoffmann, Jobst}. \enquote{The \textsf{listings}
% package}. Available from
% \textsc{ctan}, \url{https://www.ctan.org/pkg/listings}, 2025.
%
% \bibitem{minted} \textsc{Poore, Geoffrey M}. \enquote{The \textsf{minted}
% package - Highlighted source code in \hologo{LaTeX}}. Available from
% \textsc{ctan}, \url{https://www.ctan.org/pkg/minted}, 2026.
%
% \bibitem{answers} \textsc{Wright, Joseph}. \enquote{\textsf{answers} – Setting
% questions (or exercises) and answers}. Available from
% \textsc{ctan},
% \url{https://ctan.org/pkg/answers}, 2014.
%
% \bibitem{tcolorbox} \textsc{F. Sturm, Thomas}. \enquote{\textsf{tcolorbox} – Coloured boxes,
% for \hologo{LaTeX} examples and theorems, etc}. Available from
% \textsc{ctan}, \url{https://ctan.org/pkg/tcolorbox}, 2026.
%
% \bibitem{xparse} The \hologo{LaTeX} Project. \enquote{The \textsf{xparse}
% package}. Available from
% \textsc{ctan}, \url{https://www.ctan.org/pkg/xparse}, 2024.
%
% \bibitem{latex2e} The \hologo{LaTeX} Project. \enquote{The \hologo{LaTeX2e}
% sources}. Available from
% \textsc{ctan}, \url{https://ctan.org/tex-archive/macros/latex/base}, 2026.
%
% \bibitem{userguide} The \hologo{LaTeX} Project. \enquote{\hologo{LaTeX} for authors
% current version}. Available from
% \textsc{ctan}, \url{https://ctan.org/pkg/latex-base}, 2026.
%
% \bibitem{xsim} \textsc{Niederberger, Clemens}. \enquote{\textsf{xsim} – eXercise
% Sheets IMproved}. Available from
% \textsc{ctan}, \url{https://www.ctan.org/pkg/xsim}, 2023.
%
% \bibitem{latexlab} The \hologo{LaTeX} Project. \enquote{\textsf{latex-lab} – \hologo{LaTeX}
% laboratory}. Available from
% \textsc{ctan}, \url{https://www.ctan.org/pkg/latex-lab}, 2026.
%
% \bibitem{verbatim} The \hologo{LaTeX} Project. \enquote{\textsf{verbatim} – Reimplementation
% of and extensions to \hologo{LaTeX} \textsf{verbatim}}. Available from
% \textsc{ctan}, \url{https://www.ctan.org/pkg/verbatim}, 2023.
%
% \bibitem{inter3} The \hologo{LaTeX} Project. \enquote{The \hologo{LaTeX}3
% Interfaces}. Available from
% \textsc{ctan}, \url{https://www.ctan.org/pkg/l3kernel}, 2026.
%
% \bibitem{keyval} \textsc{Wright, Joseph}. \enquote{Programming
% \textsf{key–value} in \textsf{expl3}}. Available from
% \textsc{TUGboat},
% \url{https://www.tug.org/TUGboat/tb31-1/tb97wright-l3keys.pdf}, 2010.
%
% \end{thebibliography}
%
% \let\section\stdsection
%
% \section{Change history}\label{sec:changes}
%
% In this section you will find some (not all) of the changes in \mypkg*[no-index]{scontents}
% development, from the first public implementation using the \mypkg{filecontentsdef}\cite{filecontentsdef}
% package to the current version with only \mypkg{expl3}\cite{expl3}.
%
% \setlist[itemize,1]{label=\textendash,leftmargin=*,labelsep=0.5em,nosep,noitemsep}
% \newlength\descrwidth
% \settowidth{\descrwidth}{\textsf{v1.0a, (ctan), 2019-07-30} }
%
% \begin{description}[font=\small\sffamily,wide=0pt,style=multiline,leftmargin=1.1\descrwidth,nosep,noitemsep]
% \item [\fileversion{} (ctan), \filedate]
%    \begin{itemize}
%        \item Update requirement to \hologo{LaTeX} release 2026-11-01.
%        \item Fix warning for empty argument in |\Scontents| and |\Scontents*|.
%        \item Add error for empty sequence names and undefined sequences.
%        \item Check positive integers in \mykey{start}, \mykey{step}, \mykey{stop} and \mykey{width-tab} keys.
%        \item The messages for writing and overwriting files only go to the \texttt{.log} file.
%        \item Fix \mykey{wrapper} key and allow |\par| in the optional argument of |\foreachsc|.
%        \item Fix negative \mymeta{index} in |\typestored|, |\meaningsc| and |\mergesc|.
%        \item Fix the check of existing \mymeta{output files} in \hologo{ConTeXt} for files written in the same run.
%        \item Fix loading in \hologo{ConTeXt} when \mypkg{expl3} was already loaded by another module.
%        \item The messages of the environments show their start and end as written in \hologo{plainTeX} and \hologo{ConTeXt}.
%        \item The \enquote{error} |index-out-of-range| shows the limit of the sequence and the \enquote{errors} |index-out-of-range| and |empty-variable| have a help text.
%        \item Fix \mymarg{seq name} without \mymeta{index}, undefined sequences and \mymeta{index} out of range in |\mergesc|.
%        \item Fix \texttt{TAB} at the beginning of a line in |\typestored| and |\mergesc|.
%        \item Fix empty line at the beginning of |\typestored| and |\mergesc| in \hologo{plainTeX}.
%        \item Unknown \mymeta{keys} in the package options, |\setupsc| and the \mymeta{initial keys} of |\newenvsc| return an \enquote{error} that names the command.
%        \item Added regression tests for \hologo{LaTeX}, \hologo{plainTeX} and \hologo{ConTeXt}, run with |l3build check|.
%        \item New \mykey{remember} key to use the \mymeta{stored contents} before they are stored, only in \hologo{LaTeX} (GitHub issue \#1).
%        \item New \mykey{getstored} key for |\mergesc| and \mykey{getstored}, \mykey{typestored} and \mykey{meaningsc} keys for |\foreachsc| (GitHub issue \#10).
%        \item New programming interface for \mypkg{expl3}: \myhlc|\scontents_if_exist:nTF|, \myhlc|\scontents_count:n|, \myhlc|\scontents_get:nnN| and \myhlc|\scontents_map_inline:nn| (GitHub issue \#10).
%    \end{itemize}
% \item [v2.7 (ctan), 2026-06-01]
%    \begin{itemize}
%        \item Internal environment \myenv*[no-index]{verbatimsc} update for \emph{tagged} \texttt{PDF}.
%        \item Update requirement to \hologo{LaTeX} release 2026-06-01.
%        \item Add \mykey{debug-var} key for writing variables to the \texttt{.log} file.
%        \item Update and improvements documentation and examples.
%    \end{itemize}
% \item [v2.6 (ctan), 2025-11-20]
%    \begin{itemize}
%        \item Internal environment \myenv*[no-index]{verbatimsc} update for \emph{tagged} \texttt{PDF}.
%        \item Update requirement to \hologo{LaTeX} release 2025-11-01.
%    \end{itemize}
% \item [v2.5 (ctan), 2025-11-01]
%    \begin{itemize}
%        \item Replacing |\scantokens| (primitive) with \myhlc|\tl_retokenize:n|.
%        \item Cleanup warnings and details returned by |expltools|.
%        \item Update minimum required of \mypkg{expl3} to 2025-07-08.
%    \end{itemize}
% \item [v2.4 (ctan), 2025-05-15]
%    \begin{itemize}
%        \item Optimization of expansion code from `|x|' to `|e|'.
%        \item Restructuring code for documentation and implementation.
%        \item Add new keys for |\typestored| and |\meaningsc|.
%        \item Check the version of \mypkg{expl3} in \hologo{plainTeX} and \hologo{ConTeXt}.
%    \end{itemize}
% \item [v2.3 (ctan), 2025-04-23]
%    \begin{itemize}
%        \item Adapting the \myenv*[no-index]{verbatimsc} environment for \emph{tagged} \texttt{PDF}.
%        \item Update minimum required to \LaTeX{} release 2024-11-01.
%        \item Safer code for replacement |\obeyedline|.
%    \end{itemize}
% \item [v2.2 (ctan), 2025-03-26]
%    \begin{itemize}
%        \item Fix internal definition for some functions.
%        \item Replace \myhlc|\peek_charcode_ignore_spaces:NTF| by \myhlc|\peek_charcode:NTF|.
%        \item Set correct code for |\obeyedline| implement in \LaTeX{} release 2024-06-01.
%    \end{itemize}
% \item [v2.1 (ctan), 2024-06-14]
%    \begin{itemize}
%        \item Fix |\cleanseqsc| command.
%        \item Add |\mergesc| command.
%        \item Fix internal definition for seq var.
%        \item Fix internal code for |\typestored|.
%        \item Replace \myhlc|\cs_argument_spec:N| by \myhlc|\cs_parameter_spec:N|.
%        \item Detect \mypkg{l3keys2e} package (obsolete in june 2022 \LaTeX{} release).
%        \item Minor adjustments in the documentation.
%    \end{itemize}
% \item [v2.0 (ctan), 2022-04-04]
%    \begin{itemize}
%        \item Adapting the \myenv*[no-index]{verbatimsc} environment (compatibility \mypkg{verbatim} package).
%        \item Removed compatibility layer for older \hologo{LaTeX} releases.
%        \item Fix loader in \hologo{plainTeX} and \hologo{ConTeXt}.
%        \item Minor adjustments in the documentation.
%    \end{itemize}
% \item [v1.9 (ctan), 2020-01-21]
%    \begin{itemize}
%        \item Update and improvements in the internal code.
%        \item Updating the generic code for |I/O| verification.
%        \item Add \mykey{write-cmd} and \mykey{write-out} keys for |\Scontents*|.
%        \item Fix \mykey{sep} key in |\foreachsc|.
%    \end{itemize}
% \item [v1.8 (ctan), 2019-11-18]
%    \begin{itemize}
%        \item Add |\newenvsc| command.
%        \item Fix nested environment in \hologo{plainTeX} and \hologo{ConTeXt}.
%        \item Modified default value in |\getstored|.
%        \item Add \mykey{overwrite} key to reduce |I/O| operations.
%        \item Deleted an unnecessary group in the code.
%    \end{itemize}
% \item [v1.7 (ctan), 2019-10-29]
%    \begin{itemize}
%        \item The \myenv*[no-index]{verbatimsc} environment was rewritten.
%        \item Minor adjustments in documentation.
%    \end{itemize}
% \item [v1.6 (ctan), 2019-10-26]
%    \begin{itemize}
%        \item The internal behavior of |\getstored| has been modified.
%        \item The internal behavior of |\foreachsc| has been modified.
%        \item Corrected file extension for \hologo{ConTeXt}.
%        \item Remove spurious warning.
%    \end{itemize}
% \item [v1.5 (ctan), 2019-10-24]
%    \begin{itemize}
%        \item Add support for \hologo{plainTeX} and \hologo{ConTeXt}.
%        \item Split internal code for optimization.
%        \item Add support for vertical spaces in \myoarg{key \textnormal{\textcolor{gray}{=}} val}.
%        \item Add |\foreachsc| command.
%        \item Check if \mypkg{verbatim} package is loaded.
%    \end{itemize}
% \item [v1.4 (ctan), 2019-10-03]
%    \begin{itemize}
%        \item Add \mykey{store-all} key.
%        \item Messages and keys were separated.
%        \item Restructuring of documentation.
%        \item Now the version of \mypkg{expl3} is checked instead of \mypkg{xparse}.
%        \item The internal behavior of \mykey{force-eol} has been modified.
%    \end{itemize}
% \item [v1.3 (ctan), 2019-09-24]
%    \begin{itemize}
%        \item The environment \myenv*[no-index]{scontents} can now nest.
%        \item Added \mykey{force-eol}, \mykey{verb-font} and \mykey{width-tab} keys.
%        \item The extra space has been removed when you run |\getstored|.
%        \item Internal code has been rewritten more efficiently.
%        \item Remove \emph{starred argument} `|*|' for |\typestored|.
%        \item Remove \mypkg{filecontentsdef} dependency.
%        \item Changing \myhlc|\regex_replace_all:| for \myhlc|\tl_replace_all:|.
%    \end{itemize}
% \item [v1.2 (ctan), 2019-08-28]
%    \begin{itemize}
%        \item Restructuring of documentation.
%        \item Added copy of \myhlc|\tex_scantokens:|.
%    \end{itemize}
% \item [v1.1 (ctan), 2019-08-12]
%    \begin{itemize}
%        \item Extension of documentation.
%        \item Replace \myhlc|\tex_endinput:D| by \myhlc|\file_input_stop:|.
%    \end{itemize}
% \item [v1.0 (ctan), 2019-07-30]
%    \begin{itemize}
%        \item First public release.
%    \end{itemize}
% \end{description}
%
% \newpage
%
% \indexprologue{
% The italic numbers denote the pages where the corresponding entry is
% described.}
%
% \printindex[userdoc]
%
% \newpage
%
% \StartImplementation
%
% \StopEventually{^^A
% \newgeometry{top=0.5in,bottom=0.3in,left=1.0in,right=0.5in,footskip=0.2in,headheight=1cm,headsep=0.27cm}
% \addtocontents{toc}{\protect\setcounter{tocdepth}{2}}
% \cleardoublepage
% \phantomsection
% \indexprologue{
% The italic numbers denote the pages where the corresponding entry is
% described, the numbers underlined and all others indicate the line on
% which they are implemented in the package code.
% }
% \printindex
% }
%
% \section{Implementation}\label{sec:implementation}
% \addtocontents{toc}{\protect\setcounter{tocdepth}{0}}
%
% The most recent publicly released version of \mypkg*[no-index]{scontents}
% is available at \textsc{ctan}: \url{https://www.ctan.org/pkg/scontents}.
% Historical and developmental versions are available at
% \textcolor{gray}{\scriptsize\faIcon[regular]{github}}
% \url{https://github.com/pablgonz/scontents}. While general feedback via
% email is welcomed, specific bugs or feature requests should be reported
% through the issue tracker:
% \url{https://github.com/pablgonz/scontents/issues}.
%
% \begin{important}*
% All variables and functions defined in this package are private and
% are NOT intended to work or be used by another package or module,
% except the functions of the programming interface (\S\ref{sec:api}).
% \end{important}
%
% \subsection{General conventions}\label{subsec:conventions}
%
% The package is split into a \emph{loader} and a \emph{core}. The loader
% is different for each format and generates \myfile{scontents.sty} for
% \hologo{LaTeX}, \myfile{scontents.tex} for \hologo{plainTeX} and
% \myfile{t-scontents.mkiv} for \hologo{ConTeXt}, the core is shared by
% the three formats and generates \myfile{scontents-code.tex}, which is
% loaded by each loader.
%
% Since the core runs in \hologo{plainTeX} and \hologo{ConTeXt}, where
% the names of some primitives may be redefined by the format, the core
% uses the \myhlc|\tex_...:D| names for the primitives that have no
% \mypkg{expl3} interface, such as \myhlc|\tex_kern:D|,
% \myhlc|\tex_lastskip:D| or \myhlc|\tex_spacefactor:D|.
%
% Each command and environment is implemented in the same order: its
% variables, its messages, its \mymeta{keys}, its internal functions and
% finally the public command or environment.
%
% \subsection{Declaration of the package}
%
% First we set up the module name for \mypkg{docstrip} and the \mypkg{l3doc}
% class:
%    \begin{macrocode}
%<@@=scontents>
%    \end{macrocode}
%
% Now we define some common macros to hold the package date and version:
%    \begin{macrocode}
%<*loader>
\def\ScontentsFileDate{2026-11-01}%
\def\ScontentsFileVersion{2.8}%
\def\ScontentsFileDescription{Stores LaTeX contents in memory or files}%
%    \end{macrocode}
%
% The \LaTeX{} loader is quite simple, we just need to make sure of the
% minimum version for correct operation and then set interfaces up.
% The choice of \LaTeX{} release 2026-11-01 is the latest available in
% \TeX{} Live 2026 and is necessary to be able to implement
% the package's full compatibility with \emph{tagged} \texttt{PDF}.
%
%    \begin{macrocode}
%<*latex>
\NeedsTeXFormat{LaTeX2e}[2026-11-01]
\ProvidesExplPackage
  {scontents} {\ScontentsFileDate} {\ScontentsFileVersion}
  {\ScontentsFileDescription}
%</latex>
%    \end{macrocode}
%
% \subsubsection{Load \texttt{expl3-generic} and \texttt{xparse-generic} in \hologo{plainTeX} and \hologo{ConTeXt}}\label{subsubsec:generic-layer}
%
% \begin{macro}[int]
%   {
%     \c_@@_version_str,
%     \l_@@_char_value_int,
%   }
%   The \hologo{plainTeX} and \hologo{ConTeXt} loaders are similar. We
%   define the constant string \myhlc|\c_@@_version_str| with the version
%   info and add |\ExplSyntaxOn| to be able to load the frozen
%   \mypkg{xparse}\cite{xparse}. In \hologo{ConTeXt} the module is loaded
%   after \myhlc|\unprotect|, which makes `|!|' a letter, but
%   \mypkg{expl3} and \myfile{xparse-generic.tex} use `|!|' in boolean
%   expressions and \myfile{expl3-generic.tex} does not set its category
%   code, so `|!|' is set to \emph{other} before loading it and is a
%   letter again at the end (\S\ref{subsec:finish}).
%    \begin{macrocode}
%<*!latex>
%<context>\writestatus{loading}{User Module scontents v\ScontentsFileVersion}
%<context>\unprotect
%<context>\catcode`\!=12\relax
\input expl3-generic.tex
\ExplSyntaxOn
\str_const:ce { c_@@_version_str } { \ScontentsFileDate\space
  v\ScontentsFileVersion\space \ScontentsFileDescription }
\iow_log:e { Package: ~ scontents ~ \str_use:c { c_@@_version_str } }
%    \end{macrocode}
%   Outside of \LaTeX{} we can't use \mypkg{ltcmd}\cite{latex2e,userguide},
%   part of the \LaTeX{} kernel, but the old \mypkg{xparse}\cite{xparse}
%   provides \myfile{xparse-generic.tex}, which is loadable in any format.
%   The integer variable \myhlc|\l_@@_char_value_int| saves the category code
%   of `|@|' while it is loaded.
%    \begin{macrocode}
\int_new:N  \l_@@_char_value_int
\int_set:Nn \l_@@_char_value_int { \char_value_catcode:n { `\@ } }
\char_set_catcode_letter:N \@
\file_input:n { xparse-generic.tex }
\char_set_catcode:nn { `\@ } { \l_@@_char_value_int }
%</!latex>
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Checking \texttt{expl3} version}
%
% For \hologo{plainTeX}, \hologo{LaTeX} and \hologo{ConTeXt} we must check
% the minimum requirement, in this case \myhlc|\tl_retokenize:n| which
% was added in release 2025-07-08 of \mypkg{expl3} included in
% \hologo{TeX} Live 2025.
%    \begin{macrocode}
\cs_if_exist:NF \tl_retokenize:n
  {
    \msg_new:nnn { scontents } { expl-too-old }
      {
        Please~install~an~up~to~date~TeX~distribution~or~update~using~
        your~TeX~package~manager~or~from~CTAN. \\
        See~documentation.~Loading~scontents~will~abort!
      }
    \msg_fatal:nn { scontents } { expl-too-old }
    \ExplSyntaxOff
    \file_input_stop:
  }
%    \end{macrocode}
%
% \subsubsection{Preventing double loading in \hologo{plainTeX}}
%
% In \hologo{plainTeX}, check that the package isn't being loaded twice,
% \LaTeX{} and \hologo{ConTeXt} already defend against that:
%    \begin{macrocode}
%<*plain>
\tl_if_exist:NT \l_@@_cmd_name_tl
  {
    \msg_new:nnn { scontents } { already-loaded }
      {
        The~'scontents'~package~is~already~loaded.~
        Aborting~input~\msg_line_context:.
      }
    \msg_warning:nn { scontents } { already-loaded }
    \ExplSyntaxOff
    \file_input_stop:
  }
%</plain>
%</loader>
%    \end{macrocode}
%
% \subsubsection{Checking proper loader}
%
% Checking that the package was loaded with the proper loader code. This code
% was copied from \myfile{expl3-code.tex}.
%    \begin{macrocode}
%<*core>
\def\ScontentsCoreFileDate{2026-11-01}%
\begingroup
  \catcode32=10
  \endlinechar=32
  \def\next{\endgroup}%
  \expandafter\ifx\csname PackageError\endcsname\relax
    \begingroup
      \def\next{\endgroup\endgroup}%
      \def\PackageError#1#2#3%
        {%
          \endgroup
          \errhelp{#3}%
          \errmessage{#1 Error: #2!}%
        }%
  \fi
  \expandafter\ifx\csname ScontentsFileDate\endcsname\relax
    \def\next
      {%
        \PackageError{scontents}{No scontents loader detected}
          {%
            You have attempted to use the scontents code directly rather
            than using the correct loader. Loading of scontents will abort.
          }%
        \endgroup
        \endinput
      }%
  \else
    \ifx\ScontentsFileDate\ScontentsCoreFileDate
    \else
      \def\next
        {%
          \PackageError{scontents}{Mismatched scontents files detected}
            {%
              You have attempted to load scontents with mismatched files:
              probably you have one or more files 'locally installed' which
              are in conflict. Loading of scontents will abort.
            }%
          \endgroup
          \endinput
        }%
    \fi
  \fi
\next
%</core>
%    \end{macrocode}
%
% \subsection{Variables and functions by format}\label{subsec:format}
%
% We define and set the variables and the function that must be handled
% separately in order to work properly with \hologo{plainTeX}, \LaTeX{} and
% \hologo{ConTeXt}.
%
% \begin{macro}[int]{\@@_format_case:nnn}
%   The function \myhlc|\@@_format_case:nnn| leaves the argument for the
%   current format: |#1| for \LaTeX, |#2| for \hologo{plainTeX} and |#3| for
%   \hologo{ConTeXt}.
%    \begin{macrocode}
%<*loader>
\cs_new:Npn \@@_format_case:nnn #1 #2 #3
%<latex>  {#1} % LaTeX
%<plain>  {#2} % Plain/Generic
%<context>  {#3} % ConTeXt
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int,TF]{\@@_file_if_exist:n}
%   The conditional \myhlc|\@@_file_if_exist:nTF| tests if the
%   \mymeta{output file} passed in |#1| exists in the working directory.
%   In \hologo{LaTeX} and \hologo{plainTeX} it is
%   \myhlc|\file_if_exist:nTF|. In \hologo{ConTeXt} the file search keeps
%   the result found at the start of the run, so a file written by the
%   package in the same run is not found; there the test is done with
%   |lfs.isfile| of \hologo{LuaTeX}, the \mymeta{output file} is always
%   in the working directory.
%    \begin{macrocode}
%<!context>\cs_new_eq:NN \@@_file_if_exist:nTF \file_if_exist:nTF
%<*context>
\prg_new_conditional:Npnn \@@_file_if_exist:n #1 { TF }
  {
    \str_if_eq:eeTF
      {
        \lua_now:e
          { tex.write(lfs.isfile("\lua_escape:e {#1}")~and~"1"~or~"0") }
      }
      { 1 }
      { \prg_return_true: }
      { \prg_return_false: }
  }
%</context>
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{\c_@@_newline_tl}
%   The constant token list \myhlc|\c_@@_newline_tl| stores the character
%   `\myhlc|^^J|' used as end of line in the \mymeta{stored content}.
%    \begin{macrocode}
%<*!context>
\tl_const:Ne \c_@@_newline_tl { \iow_char:N \^^J }
%</!context>
%    \end{macrocode}
%   In \hologo{ConTeXt} the package does not work under LMTX, so loading
%   is aborted there. The test with \myhlc|\contextlmtxmode| is adapted
%   from the file \myfile{t-lua-widow-control.mkxl} of Max Chernoff's
%   \mypkg{lua-widow-control} package, \myhlc|\contextlmtxmode| is
%   described in \url{https://source.contextgarden.net/tex/context/base/mkxl/context.mkxl}.
%    \begin{macrocode}
%<*context>
\bool_if:NTF \contextlmtxmode
  {
    \msg_new:nnn { scontents } { luametatex }
      {
        The~'scontents'~package~doesn't~work~under~LMTX.
      }
    \msg_fatal:nn { scontents } { luametatex }
  }
  {
    \tl_const:Ne \c_@@_newline_tl { \iow_char:N \^^J }
  }
%</context>
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]
%   {
%     \g_@@_end_verbatimsc_tl,
%     \c_@@_end_env_tl,
%     \l_@@_env_name_tl,
%   }
%   The global token list \myhlc|\g_@@_end_verbatimsc_tl| matches the end of
%   the |verbatimsc| environment (\S\ref{env:verbatimsc}) in each format.
%    \begin{macrocode}
\tl_new:N \g_@@_end_verbatimsc_tl
\tl_gset_rescan:Nnn \g_@@_end_verbatimsc_tl
  {
    \char_set_catcode_other:N \\
%<*latex>
    \char_set_catcode_other:N \{
    \char_set_catcode_other:N \}
%</latex>
  }
%<latex>  { \end{verbatimsc} }
%<plain>  { \endverbatimsc }
%<context>  { \stopverbatimsc }
%    \end{macrocode}
%   The constant token list \myhlc|\c_@@_end_env_tl| matches the end of the
%   environments defined by |\newenvsc| and the token list
%   \myhlc|\l_@@_env_name_tl| stores the \emph{name} of the environment
%   being processed (\S\ref{cmd:newenvsc}).
%    \begin{macrocode}
\tl_new:N    \l_@@_env_name_tl
\tl_const:Ne \c_@@_end_env_tl
  {
    \c_backslash_str
%<latex|plain>    end
%<context>    stop
%<latex>    \c_left_brace_str
      \exp_not:N \l_@@_env_name_tl
%<latex>    \c_right_brace_str
  }
%    \end{macrocode}
% \end{macro}
%
% \subsection{Loading the package core}
%
% Now we load the core \mypkg*[no-index]{scontents} code:
%    \begin{macrocode}
\file_input:n { scontents-code.tex }
%</loader>
%    \end{macrocode}
%
% \subsection{Some kernel variants}
%
% \begin{macro}[int]{\tl_replace_all:NeV, \tl_retokenize:e}
%   Some nonstandard kernel variants.
%    \begin{macrocode}
%<*core>
\cs_generate_variant:Nn \tl_replace_all:Nnn { NeV }
\cs_generate_variant:Nn \tl_retokenize:n { e }
%    \end{macrocode}
% \end{macro}
%
% \subsection{General variables}\label{subsec:general-vars}
%
% \begin{macro}[int]{\q_@@_stop, \q_@@_mark, \s_@@_stop, \s_@@_mark}
%   Quarks and scan marks used along the code as delimiters.
%    \begin{macrocode}
\quark_new:N \q_@@_stop
\quark_new:N \q_@@_mark
\scan_new:N  \s_@@_stop
\scan_new:N  \s_@@_mark
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{\l_@@_cmd_name_tl}
%   The token list \myhlc|\l_@@_cmd_name_tl| stores the \emph{name} of the
%   command that receives the \mymeta{keys}: |\Scontents|, |\foreachsc|,
%   |\typestored|, |\meaningsc|, |\mergesc|, |\setupsc|, |\newenvsc| or
%   |\usepackage| for the options of the package. It is used in the
%   messages for unknown \mymeta{keys} (\S\ref{key:unknown-keys}).
%    \begin{macrocode}
\tl_new:N \l_@@_cmd_name_tl
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]
%   {
%     \l_@@_file_name_tl,
%     \l_@@_file_write_iow,
%     \l_@@_writing_bool,
%     \l_@@_storing_bool,
%     \l_@@_writable_bool,
%   }
%   The token list \myhlc|\l_@@_file_name_tl| stores the name of the
%   \mymeta{output file} set by the \mykey{write-env}, \mykey{write-out}
%   and \mykey{write-cmd} keys and \myhlc|\l_@@_file_write_iow| is the
%   \emph{output stream} used to write it.
%
%   The boolean variables \myhlc|\l_@@_writing_bool| and
%   \myhlc|\l_@@_storing_bool|, set by the same keys, determine whether the
%   content is written to the \mymeta{output file} and whether it is
%   stored, \myhlc|\l_@@_storing_bool| is true by default. The boolean
%   variable \myhlc|\l_@@_writable_bool| keeps track of whether the
%   \mymeta{output file} was opened by \myhlc|\@@_file_if_writable:nTF|
%   (\S\ref{fun:utility}).
%    \begin{macrocode}
\tl_new:N   \l_@@_file_name_tl
\iow_new:N  \l_@@_file_write_iow
\bool_new:N \l_@@_writing_bool
\bool_new:N \l_@@_storing_bool
\bool_new:N \l_@@_writable_bool
\bool_set_true:N \l_@@_storing_bool
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{\l_@@_seq_item_seq, \g_@@_name_sc!internal_seq}
%   The sequence \myhlc|\l_@@_seq_item_seq| stores the \mymeta{indexes}
%   of the \mymeta{stored content} requested to |\typestored|,
%   |\meaningsc| or |\mergesc| and the sequence
%   \myhlc|\g_@@_name_sc!internal_seq| is the one assembled by |\mergesc|
%   (\S\ref{cmd:mergesc}).
%    \begin{macrocode}
\seq_new:N \l_@@_seq_item_seq
\seq_new:c { g_@@_name_sc!internal_seq }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{\g_@@_last_stored_tl}
%   The token list \myhlc|\g_@@_last_stored_tl| is used by the function
%   \myhlc|\@@_lastfrom_seq:n| (\S\ref{fun:sequences}) to execute the
%   last \mymeta{stored content} outside the group.
%    \begin{macrocode}
\tl_new:N \g_@@_last_stored_tl
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{\c_@@_hidden_space_str}
%   The constant string \myhlc|\c_@@_hidden_space_str| hides the
%   \mymeta{forced space} added by \hologo{TeX} when recording content in
%   a macro. It contains the \emph{reserved phrase} `|%^^Ascheol%|', which
%   is added to the end of the \mymeta{stored content} when the key
%   \mykey{force-eol} is false.
%    \begin{macrocode}
\str_const:Ne \c_@@_hidden_space_str
  { \c_percent_str \c_circumflex_str \c_circumflex_str A scheol \c_percent_str }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{\l_@@_save_sf_int, \l_@@_save_skip}
%   Variables used by the functions \myhlc|\@@_bsphack:| and
%   \myhlc|\@@_esphack:| (\S\ref{fun:sphack}).
%    \begin{macrocode}
\int_new:N  \l_@@_save_sf_int
\skip_new:N \l_@@_save_skip
%    \end{macrocode}
% \end{macro}
%
% \subsection{General messages}\label{subsec:general-messages}
%
% \subsubsection{Definition of error messages}
%
% \begin{macro}[int]{undefined-storage, index-out-of-range}
%   The \enquote{error} |undefined-storage| is raised when the
%   \emph{sequence} passed to |\getstored|, |\foreachsc|, |\typestored|,
%   |\meaningsc|, |\mergesc|, |\countsc| or to the functions of the
%   programming interface does not exist
%   (\S\ref{fun:sequences}, \S\ref{cmd:foreachsc}, \S\ref{cmd:mergesc},
%   \S\ref{cmd:countsc}, \S\ref{fun:api}) and the \enquote{error}
%   |index-out-of-range| is raised when the \mymeta{index} is zero or its
%   absolute value is greater than the number of \mymeta{stored contents}
%   (\S\ref{fun:sequences}, \S\ref{cmd:mergesc}, \S\ref{fun:api}).
%    \begin{macrocode}
\msg_new:nnnn { scontents } { undefined-storage }
  { Storage~named~'#1'~is~not~defined. }
  { No~content~has~been~stored~in~a~sequence~named~'#1'. }
\msg_new:nnnn { scontents } { index-out-of-range }
  {
    \int_compare:nNnTF {#1} = { 0 }
      { Index~of~sequence~'#2'~cannot~be~zero. }
      {
        Index~'#1'~out~of~range~for~'#2',~the~
        \int_compare:nNnTF {#1} > { 0 }
          { maximum~is~#3. }
          { minimum~is~-#3. }
      }
  }
  {
    The~sequence~'#2'~has~#3~stored~contents,~use~an~index~from~
    1~to~#3~or~from~-#3~to~-1.
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{positive-integer, empty-store-name}
%   The \enquote{error} |positive-integer| is raised when the keys
%   \mykey{width-tab}, \mykey{start}, \mykey{step} or \mykey{stop} receive
%   a value that is not a \mymeta{positive integer}
%   (\S\ref{key:package},~\S\ref{key:foreachsc}) and the \enquote{error}
%   |empty-store-name| is raised when the name of the \emph{sequence} is
%   blank (\S\ref{fun:sequences}).
%    \begin{macrocode}
\msg_new:nnnn { scontents } { positive-integer }
  { The~key~'#1'~needs~a~positive~integer,~'#2'~given~\msg_line_context:. }
  { The~value~'#2'~is~ignored~and~the~key~'#1'~keeps~its~previous~value. }
\msg_new:nnnn { scontents } { empty-store-name }
  { Empty~sequence~name~for~storing~content~\msg_line_context:. }
  {
    The~keys~'store-env',~'store-cmd'~and~'store-all'~need~a~non-empty~
    sequence~name.~The~content~will~not~be~stored.
  }
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Definition of messages for writing files}
%
% \begin{macro}[int]{writing-file, overwrite-file, not-writing}
%   The \enquote{info} messages |writing-file| and |overwrite-file| are
%   written to the \texttt{.log} file when an \mymeta{output file} is
%   written or overwritten and the \enquote{warning} |not-writing| is
%   issued when the \mymeta{output file} already exists and the key
%   \mykey{overwrite} is not active (\S\ref{fun:utility}).
%    \begin{macrocode}
\msg_new:nnn { scontents } { writing-file }
  { Writing~file~'#1'. }
\msg_new:nnn { scontents } { overwrite-file }
  { Overwriting~file~'#1'. }
\msg_new:nnn { scontents } { not-writing }
  { File~'#1'~already~exists.~Not~writing~\msg_line_context:. }
%</core>
%    \end{macrocode}
% \end{macro}
%
% \subsection{Keys for the package}\label{key:package}
%
% \begin{macro}[int]{\l_@@_tab_width_int, \@@_set_positive_int:Nnn}
%   The integer variable \myhlc|\l_@@_tab_width_int| stores the value of
%   the \mykey{width-tab} key. The function
%   \myhlc|\@@_set_positive_int:Nnn| sets the integer variable passed in
%   |#1| to the value passed in |#3| only if it is a
%   \mymeta{positive integer}, otherwise it raises the \enquote{error}
%   |positive-integer| naming the \mymeta{key} passed in |#2| and the
%   value is ignored. It is used by the \mykey{width-tab} key and by the
%   \mykey{start}, \mykey{step} and \mykey{stop} keys of |\foreachsc|
%   (\S\ref{key:foreachsc}). The core code does not use `|!|' in boolean
%   expressions, so it does not depend on the category code of `|!|' in
%   \hologo{ConTeXt} (\S\ref{subsubsec:generic-layer}).
%    \begin{macrocode}
%<*core>
\int_new:N \l_@@_tab_width_int
\cs_new_protected:Npn \@@_set_positive_int:Nnn #1 #2 #3
  {
    \bool_lazy_or:nnTF
      { \tl_if_blank_p:n {#3} }
      { \int_compare_p:nNn {#3} < { 1 } }
      { \msg_error:nnnn { scontents } { positive-integer } {#2} {#3} }
      { \int_set:Nn #1 {#3} }
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]
%   {
%     store-env,
%     store-cmd,
%     verb-font,
%     print-env,
%     print-cmd,
%     force-eol,
%     overwrite,
%     width-tab,
%     print-all,
%     store-all,
%     debug-var,
%     remember,
%     unknown,
%   }
%   We define the common \mymeta{keys} used by the options passed to the
%   package, by |\setupsc| and by the environments and commands. The
%   unknown \mymeta{keys} are passed to \myhlc|\@@_unknown_keys_cmd:n|
%   (\S\ref{key:unknown-keys}), which names the command from
%   \myhlc|\l_@@_cmd_name_tl|: |\usepackage| for the options of the
%   package, |\setupsc| or |\newenvsc| for the \mymeta{initial keys} of
%   an environment.
%    \begin{macrocode}
\keys_define:nn { scontents }
  {
    store-env .tl_set:N         = \l_@@_name_seq_env_tl,
    store-env .initial:n        = contents,
    store-env .value_required:n = true,
    store-cmd .tl_set:N         = \l_@@_name_seq_cmd_tl,
    store-cmd .initial:n        = contents,
    store-cmd .value_required:n = true,
    verb-font .tl_set:N         = \l_@@_verb_font_tl,
    verb-font .value_required:n = true,
    print-env .bool_set:N       = \l_@@_print_env_bool,
    print-env .initial:n        = false,
    print-env .default:n        = true,
    print-cmd .bool_set:N       = \l_@@_print_cmd_bool,
    print-cmd .initial:n        = false,
    print-cmd .default:n        = true,
    force-eol .bool_set:N       = \l_@@_forced_eol_bool,
    force-eol .initial:n        = false,
    force-eol .default:n        = true,
    overwrite .bool_set:N       = \l_@@_overwrite_bool,
    overwrite .initial:n        = false,
    overwrite .default:n        = true,
    width-tab .code:n           =
      { \@@_set_positive_int:Nnn \l_@@_tab_width_int { width-tab } {#1} },
    width-tab .initial:n        = 1,
    width-tab .value_required:n = true,
    print-all .meta:n           = { print-env = #1, print-cmd = #1 },
    print-all .default:n        = true,
    store-all .meta:n           = { store-env = #1, store-cmd = #1 },
    store-all .value_required:n = true,
    debug-var .bool_set:N       = \l_@@_debug_var_bool,
    debug-var .initial:n        = true,
    debug-var .default:n        = true,
    remember  .code:n           = { \@@_remember:n {#1} },
    remember  .value_required:n = true,
    remember  .usage:n          = preamble,
    unknown   .code:n           = { \@@_unknown_keys_cmd:n {#1} },
  }
%</core>
%    \end{macrocode}
%   The default value of the \mykey{verb-font} key depends on the format.
%    \begin{macrocode}
%<loader>\keys_define:nn { scontents }
%<latex>  { verb-font .initial:n = \ttfamily }
%<plain|context>  { verb-font .initial:n = \tt }
%    \end{macrocode}
%   In \LaTeX{} the \mymeta{keys} passed as options to the package are
%   processed and an unknown \mymeta{key} returns an \enquote{error}.
%    \begin{macrocode}
%<*latex>
\tl_set:Nn \l_@@_cmd_name_tl { usepackage }
\ProcessKeyOptions [ scontents ]
%</latex>
%    \end{macrocode}
% \end{macro}
%
% \subsection{Handling unknown keys}\label{key:unknown-keys}
%
% The \mymeta{keys} that are not known by the environments and the
% commands are passed to the functions defined here. The name of the
% \mymeta{key} is taken from \myhlc|\l_keys_key_str| and the value, if
% any, is passed as argument.
%
% \subsubsection{Definition of error messages for unknown keys}
%
% \begin{macro}[int]{env-key-unknown, env-key-value-unknown}
%   The \enquote{errors} |env-key-unknown| and |env-key-value-unknown|
%   are raised when an unknown \mymeta{key}, without or with value, is
%   passed to an environment defined by |\newenvsc| (\S\ref{key:newenvsc}).
%    \begin{macrocode}
%<*core>
\msg_new:nnnn { scontents } { env-key-unknown }
  {
    The~key~'#1'~is~unknown~by~environment~
    '\l_@@_env_name_tl'~and~is~being~ignored.
  }
  {
    The~environment~'\l_@@_env_name_tl'~does~not~have~a~key~called~'#1'.\\
    Check~that~you~have~spelled~the~key~name~correctly.
  }
\msg_new:nnnn { scontents } { env-key-value-unknown }
  {
    The~key~'#1=#2'~is~unknown~by~environment~
    '\l_@@_env_name_tl'~and~is~being~ignored.
  }
  {
    The~environment~'\l_@@_env_name_tl'~does~not~have~a~key~called~'#1'.\\
    Check~that~you~have~spelled~the~key~name~correctly.
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{cmd-key-unknown, cmd-key-value-unknown}
%   The \enquote{errors} |cmd-key-unknown| and |cmd-key-value-unknown|
%   are raised when an unknown \mymeta{key}, without or with value, is
%   passed to the commands |\Scontents|, |\foreachsc|, |\typestored|,
%   |\meaningsc|, |\mergesc| or |\setupsc|, to the \mymeta{initial keys}
%   of |\newenvsc| or as an option of the package
%   (\S\ref{key:package}, \S\ref{key:Scontents}, \S\ref{key:foreachsc},
%   \S\ref{key:typemeaning}).
%    \begin{macrocode}
\msg_new:nnnn { scontents } { cmd-key-unknown }
  {
    The~key~'#1'~is~unknown~by~command~
    \c_backslash_str \l_@@_cmd_name_tl \c_space_tl
    and~is~being~ignored~\msg_line_context:.
  }
  {
    The~command~\c_backslash_str \l_@@_cmd_name_tl \c_space_tl
    does~not~have~a~key~called~'#1'.\\
    Check~that~you~have~spelled~the~key~name~correctly.
  }
\msg_new:nnnn { scontents } { cmd-key-value-unknown }
  {
    The~key~'#1=#2'~is~unknown~by~command~
    \c_backslash_str \l_@@_cmd_name_tl \c_space_tl
    and~is~being~ignored~\msg_line_context:.
  }
  {
    The~command~\c_backslash_str \l_@@_cmd_name_tl \c_space_tl
    does~not~have~a~key~called~'#1'.\\
    Check~that~you~have~spelled~the~key~name~correctly.
  }
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Internal functions for unknown keys}
%
% \begin{macro}[int]{\@@_unknown_keys_env:n, \@@_unknown_keys_env:nn}
%   The function \myhlc|\@@_unknown_keys_env:n| raises the
%   \enquote{error} for an unknown \mymeta{key} passed to an environment
%   defined by |\newenvsc|.
%    \begin{macrocode}
\cs_new_protected:Npn \@@_unknown_keys_env:n #1
  { \exp_args:NV \@@_unknown_keys_env:nn \l_keys_key_str {#1} }
\cs_new_protected:Npn \@@_unknown_keys_env:nn #1 #2
  {
    \tl_if_blank:nTF {#2}
      { \msg_error:nnn { scontents } { env-key-unknown } {#1} }
      { \msg_error:nnnn { scontents } { env-key-value-unknown } {#1} {#2} }
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{\@@_unknown_keys_cmd:n, \@@_unknown_keys_cmd:nn}
%   The function \myhlc|\@@_unknown_keys_cmd:n| raises the
%   \enquote{error} for an unknown \mymeta{key} passed to the commands
%   |\Scontents|, |\foreachsc|, |\mergesc| and |\setupsc|, to the
%   \mymeta{initial keys} of |\newenvsc| and to the package.
%    \begin{macrocode}
\cs_new_protected:Npn \@@_unknown_keys_cmd:n #1
  { \exp_args:NV \@@_unknown_keys_cmd:nn \l_keys_key_str {#1} }
\cs_new_protected:Npn \@@_unknown_keys_cmd:nn #1 #2
  {
    \tl_if_blank:nTF {#2}
      { \msg_error:nnn { scontents } { cmd-key-unknown } {#1} }
      { \msg_error:nnnn { scontents } { cmd-key-value-unknown } {#1} {#2} }
  }
%    \end{macrocode}
% \end{macro}
%
% \subsection{Utility functions}\label{fun:utility}
%
% \begin{macro}[int]
%   {
%     \@@_use_delimit_by_s_stop:nw,
%     \@@_use_i_delimit_by_s_stop:nw,
%     \@@_use_none_delimit_by_s_stop:w,
%     \@@_use_none_delimit_by_q_stop:w,
%   }
%   Functions used in the implementation of |\newenvsc|
%   (\S\ref{fun:newenvsc}) and |\mergesc| (\S\ref{cmd:mergesc}).
%    \begin{macrocode}
\cs_new:Npn \@@_use_delimit_by_s_stop:nw #1 \s_@@_stop {#1}
\cs_new:Npn \@@_use_i_delimit_by_s_stop:nw #1 #2 \s_@@_stop {#1}
\cs_new:Npn \@@_use_none_delimit_by_s_stop:w #1 \s_@@_stop { }
\cs_new:Npn \@@_use_none_delimit_by_q_stop:w #1 \q_@@_stop { }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int,TF]{\@@_tl_if_head_is_q_mark:n}
%   The conditional \myhlc|\@@_tl_if_head_is_q_mark:nTF| tests if the head
%   of the token list is \myhlc|\q_@@_mark|.
%    \begin{macrocode}
\prg_new_protected_conditional:Npnn \@@_tl_if_head_is_q_mark:n #1
  { F, TF }
  {
    \exp_after:w \if_meaning:w
      \exp_after:w
        \q_@@_mark \@@_use_i_delimit_by_s_stop:nw #1 ? \s_@@_stop
      \prg_return_true:
    \else:
      \prg_return_false:
    \fi:
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{\@@_remove_trailing_eol:N, \@@_remove_trailing_eol:w}
%   The function \myhlc|\@@_remove_trailing_eol:N| removes the string
%   \myhlc|\c_@@_hidden_space_str| from the end of the token list passed in
%   |#1|. It is used by |\typestored| (\S\ref{cmd:typestored}) and
%   |\mergesc| (\S\ref{cmd:mergesc}).
%    \begin{macrocode}
\cs_new_protected:Npe \@@_remove_trailing_eol:N #1
  {
    \exp_not:N \exp_after:w \exp_not:N \@@_remove_trailing_eol:w
      #1 \s_@@_stop \c_@@_hidden_space_str \s_@@_stop \s_@@_mark #1
  }
\use:e
  {
    \cs_new_protected:Npn \exp_not:N \@@_remove_trailing_eol:w #1
        \c_@@_hidden_space_str \s_@@_stop #2 \s_@@_mark #3
  }   {
        \tl_set:Ne #3
          {
            \tl_if_empty:nTF {#2}
              { \exp_not:o { \@@_use_delimit_by_s_stop:nw #1 } }
              { \exp_not:n {#1} }
          }
      }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int,TF]{\@@_file_if_writable:n}
%   The conditional \myhlc|\@@_file_if_writable:nTF| tests if the
%   \mymeta{output file} passed in |#1| can be written, according to the
%   \mykey{write-env}, \mykey{write-cmd}, \mykey{write-out} and
%   \mykey{overwrite} keys, and issues the messages for writing files
%   (\S\ref{subsec:general-messages}). The \mymeta{output file} is
%   searched with \myhlc|\@@_file_if_exist:nTF|.
%    \begin{macrocode}
\prg_new_protected_conditional:Npnn \@@_file_if_writable:n #1 { T, TF }
  {
    \bool_if:NTF \l_@@_writing_bool
      {
        \@@_file_if_exist:nTF {#1}
          {
            \bool_if:NTF \l_@@_overwrite_bool
              {
                \msg_info:nne { scontents } { overwrite-file } {#1}
                \prg_return_true:
              }
              {
                \msg_warning:nne { scontents } { not-writing } {#1}
                \prg_return_false:
              }
          }
          {
            \msg_info:nne { scontents } { writing-file } {#1}
            \prg_return_true:
          }
      }
      { \prg_return_false: }
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{\@@_file_write_cmd:nn, \@@_file_write_cmd:VV}
%   The function \myhlc|\@@_file_write_cmd:nn| writes the content passed
%   in |#2| to the \mymeta{output file} passed in |#1|, it is used by the
%   commands.
%    \begin{macrocode}
\cs_new_protected:Npn \@@_file_write_cmd:nn #1 #2
  {
    \@@_file_if_writable:nT {#1}
      {
        \iow_open:Nn \l_@@_file_write_iow {#1}
        \iow_now:Nn  \l_@@_file_write_iow {#2}
        \iow_close:N \l_@@_file_write_iow
      }
  }
\cs_generate_variant:Nn \@@_file_write_cmd:nn { VV }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{\@@_set_write_out:n, \@@_set_write_store:n}
%   The function \myhlc|\@@_set_write_out:n| sets the name of the
%   \mymeta{output file} passed in |#1| and only writes the content, it is
%   used by the \mykey{write-out} key. The function
%   \myhlc|\@@_set_write_store:n| also stores the content, it is used by
%   the \mykey{write-env} and \mykey{write-cmd} keys
%   (\S\ref{key:newenvsc},~\S\ref{key:Scontents},~\S\ref{key:typemeaning}).
%    \begin{macrocode}
\cs_new_protected:Npn \@@_set_write_out:n #1
  {
    \bool_set_false:N \l_@@_storing_bool
    \bool_set_true:N \l_@@_writing_bool
    \tl_set:Nn \l_@@_file_name_tl {#1}
  }
\cs_new_protected:Npn \@@_set_write_store:n #1
  {
    \@@_set_write_out:n {#1}
    \bool_set_true:N \l_@@_storing_bool
  }
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Functions for \texttt{TAB} and \texttt{verbatimsc}}
%
% \begin{macro}[int]{\@@_tab:, \@@_par:}
%   Control sequences to replace the tab `\myhlc|^^I|' and form feed `\myhlc|^^L|'
%   characters.
%    \begin{macrocode}
\cs_new:Ne \@@_tab: { \c_space_tl }
\cs_new:Nn \@@_par: { ^^J ^^J }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{\@@_tabs_to_spaces:}
%   In a \emph{verbatim} context the \texttt{TAB} character is made active
%   and set equal to \myhlc|\@@_tabs_to_spaces:|, to produce as many spaces
%   as the \mykey{width-tab} key was set to. The spaces are \emph{active}
%   characters, the same as the spaces of the \emph{verbatim} context: a
%   space token at the beginning of a line would be dropped in vertical
%   mode and the \texttt{TAB} that indent a line would be lost. The
%   \emph{active} space is made with \myhlc|\tex_lowercase:D| from the
%   \emph{active} character `\myhlc|^^@|', since \myhlc|\char_generate:nn|
%   would expand it while defining the function.
%    \begin{macrocode}
\group_begin:
  \char_set_catcode_active:N \^^@
  \char_set_lccode:nn { 0 } { 32 }
  \tex_lowercase:D
    {
      \group_end:
      \cs_new:Npn \@@_tabs_to_spaces:
        { \prg_replicate:nn { \l_@@_tab_width_int } { ^^@ } }
    }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{\@@_do_noligs:N}
%   The function \myhlc|\@@_do_noligs:N| is an alternative definition for
%   \LaTeXe's \myhlc|\do@noligs| which makes sure to not consume the
%   following space tokens. The \LaTeXe{} version ends with
%   \myhlc|\char`#1|, which leaves \TeX{} still looking for an
%   \mymeta{optional~space}.
%    \begin{macrocode}
\cs_new_protected:Npn \@@_do_noligs:N #1
  {
    \char_set_catcode_active:N #1
    \cs_set:cpe { @@_active_char_ \token_to_str:N #1 : }
      {
        \mode_leave_vertical:
        \tex_kern:D \c_zero_dim
        \tex_char:D `\exp_not:N #1
      }
    \char_set_active_eq:Nc #1 { @@_active_char_ \token_to_str:N #1 : }
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]
%   {
%     \@@_set_active_eq:NN,
%     \@@_plain_disable_outer_par:,
%     \@@_make_control_chars_active:,
%   }
%   Shortcut definitions for common catcode changes. The `\myhlc|^^L|' needs a
%   special treatment in \hologo{plainTeX} because it is an
%   \myhlc|\outer| token there.
%    \begin{macrocode}
\cs_new_protected:Npn \@@_set_active_eq:NN #1
  {
    \char_set_catcode_active:N #1
    \char_set_active_eq:NN #1
  }
%</core>
%<*loader>
\group_begin:
%<plain>  \char_set_catcode_active:n { `\* }
  \cs_new_protected:Nn \@@_plain_disable_outer_par:
%<*plain>
    {
      \group_begin:
        \char_set_lccode:nn { `\* } { `\^^L }
        \tex_lowercase:D { \group_end:
        \tex_let:D * \scan_stop:
      }
    }
%</plain>
%<latex|context>    { }
\group_end:
%</loader>
%<*core>
\cs_new_protected:Nn \@@_make_control_chars_active:
  {
    \@@_plain_disable_outer_par:
    \@@_set_active_eq:NN \^^I \@@_tab:
    \@@_set_active_eq:NN \^^L \@@_par:
    \@@_set_active_eq:NN \^^M \@@_ret:w
  }
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Functions \cs[no-index]{@bsphack} and \cs[no-index]{@esphack}}\label{fun:sphack}
%
% \begin{macro}[int]{\@@_bsphack:, \@@_esphack:}
%   We emulate \myhlc|\@bsphack| and \myhlc|\@esphack| for \hologo{plainTeX}
%   and \hologo{ConTeXt}, this is necessary to prevent \emph{unwanted
%   spaces} when the \mykey{print-cmd} key is false. In \LaTeX{} the
%   kernel definitions are used.
%    \begin{macrocode}
\cs_new_protected:Nn \@@_bsphack:
  {
    \scan_stop:
    \mode_if_horizontal:T
      {
        \skip_set_eq:NN \l_@@_save_skip \tex_lastskip:D
        \int_set_eq:NN \l_@@_save_sf_int \tex_spacefactor:D
      }
  }
\cs_new_protected:Nn \@@_esphack:
  {
    \scan_stop:
    \mode_if_horizontal:T
      {
        \int_set_eq:NN \tex_spacefactor:D \l_@@_save_sf_int
        \dim_compare:nNnT { \l_@@_save_skip } > { \c_zero_skip }
          {
            \skip_if_eq:nnT { \tex_lastskip:D } { \c_zero_skip }
              {
                \nobreak
                \skip_horizontal:n { \c_zero_skip }
              }
            \tex_ignorespaces:D
          }
      }
  }
%</core>
%<*latex>
\cs_gset_eq:NN \@@_bsphack: \@bsphack
\cs_gset_eq:NN \@@_esphack: \@esphack
%</latex>
%    \end{macrocode}
% \end{macro}
%
% \subsection{Functions for sequences}\label{fun:sequences}
%
% The \emph{storage system} of the package \mypkg*[no-index]{scontents} is
% done using |seq| variables. Here we set up the functions that manage them.
%
% \begin{macro}[int]{\@@_append_contents:nn, \@@_append_contents:Ve}
%   The function \myhlc|\@@_append_contents:nn| creates the \emph{sequence}
%   passed in |#1| if it does not exist and appends the \mymarg{body env}
%   of an environment or the \mymarg{argument} of a command, passed in
%   |#2|, to the right of the \emph{sequence}.
%    \begin{macrocode}
%<*core>
\cs_new_protected:Npn \@@_append_contents:nn #1 #2
  {
    \seq_if_exist:cF { g_@@_name_#1_seq }
      { \seq_new:c { g_@@_name_#1_seq } }
    \seq_gput_right:cn { g_@@_name_#1_seq } {#2}
  }
\cs_generate_variant:Nn \@@_append_contents:nn { Ve }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{\@@_store_to_seq:NN}
%   The function \myhlc|\@@_store_to_seq:NN| writes the recorded content
%   in |#1| to the \texttt{.log} file if \mykey{debug-var} is true and
%   stores it in the \emph{sequence} named by |#2|.
%    \begin{macrocode}
\cs_new_protected:Npn \@@_store_to_seq:NN #1 #2
  {
    \bool_if:NT \l_@@_debug_var_bool
      {
        \tl_log:N #1
      }
    \@@_append_contents:Ve #2 { \exp_not:V #1 }
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{\@@_finish_storing:NNN}
%   The function \myhlc|\@@_finish_storing:NNN| works only in the
%   \emph{storing mode}, when the \mykey{write-out} key is not active. If
%   the key \mykey{force-eol} is false, its default value,
%   \myhlc|\c_@@_hidden_space_str| is added to the end of the token list
%   passed in |#1|, which contains the \mymarg{body env} of an environment
%   or the \mymarg{argument} of |\Scontents|.
%
%   Then \myhlc|\@@_store_to_seq:NN| stores the content in the
%   \emph{sequence} named by |#2| and, if the boolean passed in |#3|, set
%   by the \mykey{print-env} or \mykey{print-cmd} key, is true, the content
%   is printed from the \emph{sequence} by \myhlc|\@@_lastfrom_seq:V|. If
%   the \emph{name} of the \emph{sequence} is blank, the \enquote{error}
%   |empty-store-name| is raised and nothing is stored or printed.
%    \begin{macrocode}
\cs_new_protected:Npn \@@_finish_storing:NNN #1 #2 #3
  {
    \bool_if:NT \l_@@_storing_bool
      {
        \tl_if_blank:VTF #2
          { \msg_error:nn { scontents } { empty-store-name } }
          {
            \bool_if:NF \l_@@_forced_eol_bool
              { \tl_put_right:Ne #1 { \c_@@_hidden_space_str } }
            \@@_store_to_seq:NN #1 #2
            \bool_if:NT #3 { \@@_lastfrom_seq:V #2 }
          }
      }
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{\@@_seq_count:n, \@@_seq_item:nn}
% \begin{macro}[int,TF]{\@@_seq_if_exist:n}
%   A \emph{sequence} set by the \mykey{remember} key has a second copy
%   with the \mymeta{stored contents} of the previous compilation, whose
%   name uses |prev| instead of |name| (\S\ref{subsec:remember}). The
%   conditional \myhlc|\@@_seq_if_exist:nTF| tests if any of the two
%   \emph{sequences} named by |#1| exists, the function
%   \myhlc|\@@_seq_count:n| returns the larger number of
%   \mymeta{stored contents} of the two, or |0| if none exists, and the
%   function \myhlc|\@@_seq_item:nn| returns the \mymeta{stored content}
%   at the \mymeta{index} passed in |#2|, from the previous compilation
%   if it has it and from the current one otherwise. Without
%   \mykey{remember}, and always in \hologo{plainTeX} and
%   \hologo{ConTeXt}, only the current \emph{sequence} exists.
%    \begin{macrocode}
\prg_new_conditional:Npnn \@@_seq_if_exist:n #1 { TF }
  {
    \bool_lazy_or:nnTF
      { \seq_if_exist_p:c { g_@@_name_#1_seq } }
      { \seq_if_exist_p:c { g_@@_prev_#1_seq } }
      { \prg_return_true: }
      { \prg_return_false: }
  }
\cs_new:Npn \@@_seq_count:n #1
  {
    \int_max:nn
      {
        \seq_if_exist:cTF { g_@@_name_#1_seq }
          { \seq_count:c { g_@@_name_#1_seq } }
          { 0 }
      }
      {
        \seq_if_exist:cTF { g_@@_prev_#1_seq }
          { \seq_count:c { g_@@_prev_#1_seq } }
          { 0 }
      }
  }
\cs_new:Npn \@@_seq_item:nn #1 #2
  {
    \bool_lazy_and:nnTF
      { \seq_if_exist_p:c { g_@@_prev_#1_seq } }
      {
        \int_compare_p:nNn { \int_abs:n {#2} }
          < { \seq_count:c { g_@@_prev_#1_seq } + 1 }
      }
      { \seq_item:cn { g_@@_prev_#1_seq } {#2} }
      { \seq_item:cn { g_@@_name_#1_seq } {#2} }
  }
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}[int]
%   {
%     \@@_getfrom_seq:Nn,
%     \@@_getfrom_seq:nNn,
%     \@@_getfrom_seq_aux:nnn,
%     \@@_getfrom_seq:nn,
%     \@@_getfrom_seq:nnn,
%   }
%   The function \myhlc|\@@_getfrom_seq:Nn| retrieves the
%   \mymeta{stored contents} whose \mymeta{indexes} are in the sequence
%   passed in |#1| from the \emph{sequence} named by |#2| and the function
%   \myhlc|\@@_getfrom_seq:nn| retrieves the one whose \mymeta{index} is
%   passed in |#1|, both with \myhlc|\@@_seq_item:nn|. Both raise the
%   \enquote{errors} |undefined-storage| and |index-out-of-range|
%   (\S\ref{subsec:general-messages}).
%    \begin{macrocode}
\cs_new:Npn \@@_getfrom_seq:Nn #1 #2
  {
    \@@_seq_if_exist:nTF {#2}
      {
        \exp_args:Nf \@@_getfrom_seq:nNn
          { \@@_seq_count:n {#2} } #1 {#2}
      }
      { \msg_expandable_error:nnn { scontents } { undefined-storage } {#2} }
  }
\cs_new:Npn \@@_getfrom_seq:nNn #1 #2 #3
  {
    \seq_map_tokens:Nn #2 { \@@_getfrom_seq_aux:nnn {#1} {#3} }
  }
\cs_new:Npn \@@_getfrom_seq_aux:nnn #1 #2 #3
  {
    \exp_args:Nnf \use:n
      { \@@_getfrom_seq:nnn {#1} } { \int_eval:n {#3} } {#2}
  }
\cs_new:Npn \@@_getfrom_seq:nn #1 #2
  {
    \@@_seq_if_exist:nTF {#2}
      {
        \exp_args:Nf \@@_getfrom_seq:nnn
          { \@@_seq_count:n {#2} }
          {#1} {#2}
      }
      { \msg_expandable_error:nnn { scontents } { undefined-storage } {#2} }
  }
\cs_new:Npn \@@_getfrom_seq:nnn #1 #2 #3
  {
    \bool_lazy_or:nnTF
      { \int_compare_p:nNn {#2} = { 0 } }
      { \int_compare_p:nNn { \int_abs:n {#2} } > {#1} }
      {
        \msg_expandable_error:nnnnn { scontents } { index-out-of-range }
          {#2} {#3} {#1}
      }
      { \@@_seq_item:nn {#3} {#2} }
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{\@@_lastfrom_seq:n, \@@_lastfrom_seq:V}
%   The function \myhlc|\@@_lastfrom_seq:n| saves the last
%   \mymeta{stored content} of the \emph{sequence} named by |#1| in
%   \myhlc|\g_@@_last_stored_tl| and rescans it with
%   \myhlc|\tl_retokenize:V| after the group, when the keys
%   \mykey{print-env} or \mykey{print-cmd} are active.
%    \begin{macrocode}
\cs_new_protected:Npn \@@_lastfrom_seq:n #1
  {
    \tl_gset:Ne \g_@@_last_stored_tl
      {
        \seq_item:cn { g_@@_name_#1_seq } { -1 }
      }
    \group_insert_after:N \tl_retokenize:V
    \group_insert_after:N \g_@@_last_stored_tl
    \group_insert_after:N \tl_gclear:N
    \group_insert_after:N \g_@@_last_stored_tl
  }
\cs_generate_variant:Nn \@@_lastfrom_seq:n { V }
%</core>
%    \end{macrocode}
% \end{macro}
%
% \subsection{Remembering contents between compilations}\label{subsec:remember}
%
% The \mykey{remember} key (\S\ref{key:package}) makes the
% \mymeta{stored contents} of some \emph{sequences} available before they
% are stored, as |\label| and |\ref| do with the references. At the end
% of the document the \mymeta{stored contents} of these \emph{sequences}
% are written to the file |\jobname.sct| and at the beginning of
% the next compilation they are read in a second \emph{sequence}, that
% is used by \myhlc|\@@_seq_item:nn| (\S\ref{fun:sequences}). Each line
% of the file has the name of the \emph{sequence} and one
% \mymeta{stored content}, both converted to hexadecimal digits and
% separated by `|=|', so that any character can be written and read
% again. This is only available in \hologo{LaTeX}.
%
% \subsubsection{Definition of variables for remembering contents}
%
% \begin{macro}[int]{\g_@@_remember_seq, \g_@@_remember_pending_bool}
%   The global \emph{sequence} \myhlc|\g_@@_remember_seq| stores, as
%   strings, the names of the \emph{sequences} set by the
%   \mykey{remember} key and the boolean
%   \myhlc|\g_@@_remember_pending_bool| is true when a
%   \mymeta{stored content} of one of them is requested and it is not
%   available yet.
%    \begin{macrocode}
%<*core>
\seq_new:N  \g_@@_remember_seq
\bool_new:N \g_@@_remember_pending_bool
%</core>
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]
%   {
%     \g_@@_remember_ior,
%     \g_@@_remember_iow,
%     \g_@@_remember_old_str,
%     \l_@@_remember_new_str,
%     \l_@@_remember_name_str,
%     \l_@@_remember_item_str,
%   }
%   The streams \myhlc|\g_@@_remember_ior| and \myhlc|\g_@@_remember_iow|
%   read and write the file |\jobname.sct|. The string
%   \myhlc|\g_@@_remember_old_str| saves the lines read from the file and
%   \myhlc|\l_@@_remember_new_str| the lines written, to compare them at
%   the end of the document, and the strings
%   \myhlc|\l_@@_remember_name_str| and \myhlc|\l_@@_remember_item_str|
%   save the name of the \emph{sequence} and the \mymeta{stored content}
%   of a line.
%    \begin{macrocode}
%<*latex>
\ior_new:N \g_@@_remember_ior
\iow_new:N \g_@@_remember_iow
\str_new:N \g_@@_remember_old_str
\str_new:N \l_@@_remember_new_str
\str_new:N \l_@@_remember_name_str
\str_new:N \l_@@_remember_item_str
%</latex>
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Definition of error messages for remembering contents}
%
% \begin{macro}[int]{remember-latex-only}
%   The \enquote{error} |remember-latex-only| is raised when the
%   \mykey{remember} key is used in \hologo{plainTeX} or \hologo{ConTeXt}.
%    \begin{macrocode}
%<*core>
\msg_new:nnnn { scontents } { remember-latex-only }
  { The~key~'remember'~is~only~available~in~LaTeX~\msg_line_context:. }
  {
    The~stored~contents~can~only~be~used~after~they~are~stored~
    in~this~format.~The~key~is~ignored.
  }
%</core>
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Definition of messages for remembering contents}
%
% \begin{macro}[int]{remember-rerun, remember-undefined}
%   The \enquote{warning} |remember-rerun| is issued at the end of the
%   document when the lines written to |\jobname.sct| are not the
%   ones read from it, and otherwise the \enquote{warning}
%   |remember-undefined| when a \mymeta{stored content} was requested and
%   it was not available.
%    \begin{macrocode}
%<*latex>
\msg_new:nnn { scontents } { remember-rerun }
  { Stored~contents~may~have~changed.~Rerun~to~get~them~right. }
\msg_new:nnn { scontents } { remember-undefined }
  { There~were~undefined~stored~contents. }
%</latex>
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Internal functions for remembering contents}
%
% \begin{macro}[int]{\@@_remember:n}
%   The function \myhlc|\@@_remember:n|, used by the \mykey{remember}
%   key, adds each name of the comma separated list passed in |#1| to
%   \myhlc|\g_@@_remember_seq| as a string, only once. In
%   \hologo{plainTeX} and \hologo{ConTeXt} it raises the
%   \enquote{error} |remember-latex-only|.
%    \begin{macrocode}
%<*core>
\cs_new_protected:Npn \@@_remember:n #1
  {
    \@@_format_case:nnn
      {
        \clist_map_inline:nn {#1}
          {
            \seq_if_in:NeF \g_@@_remember_seq { \tl_to_str:n {##1} }
              { \seq_gput_right:Ne \g_@@_remember_seq { \tl_to_str:n {##1} } }
          }
      }
      { \msg_error:nn { scontents } { remember-latex-only } }
      { \msg_error:nn { scontents } { remember-latex-only } }
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int,TF]{\@@_if_pending:n}
% \begin{macro}[int]{\@@_if_pending:neF}
%   The conditionals \myhlc|\@@_if_pending:nnT| and
%   \myhlc|\@@_if_pending:nnF| test if the \mymeta{stored content} at the
%   \mymeta{index} passed in |#2| of the remembered \emph{sequence} named
%   by |#1| is not available yet, that is, if its absolute value is
%   greater than the number of \mymeta{stored contents} of both copies. In
%   that case \myhlc|\g_@@_remember_pending_bool| is set to true and the
%   commands print nothing. For the \emph{sequences} that are not
%   remembered it is always false and the \enquote{errors} of the commands
%   are raised as usual.
%    \begin{macrocode}
\prg_new_protected_conditional:Npnn \@@_if_pending:nn #1 #2 { T, F }
  {
    \bool_lazy_and:nnTF
      { \seq_if_exist_p:c { g_@@_prev_#1_seq } }
      { \int_compare_p:nNn { \int_abs:n {#2} } > { \@@_seq_count:n {#1} } }
      {
        \bool_gset_true:N \g_@@_remember_pending_bool
        \prg_return_true:
      }
      { \prg_return_false: }
  }
\prg_generate_conditional_variant:Nnn \@@_if_pending:nn { ne } { F }
%</core>
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}[int]
%   {
%     \@@_remember_read:,
%     \@@_remember_read_line:n,
%     \@@_remember_read_line:w,
%   }
%   The function \myhlc|\@@_remember_read:| reads the file
%   |\jobname.sct|, if it exists, line by line with
%   \myhlc|\@@_remember_read_line:n|, and creates an empty copy of the
%   remembered \emph{sequences} that are not in the file. The function
%   \myhlc|\@@_remember_read_line:w| converts the name of the
%   \emph{sequence} from hexadecimal digits and, if it is remembered,
%   saves the line in \myhlc|\g_@@_remember_old_str| and adds the
%   \mymeta{stored content}, converted from hexadecimal digits, to the
%   copy of the previous compilation. The lines of the
%   \emph{sequences} that are no longer remembered are ignored.
%    \begin{macrocode}
%<*latex>
\cs_new_protected:Npn \@@_remember_read:
  {
    \ior_open:NnT \g_@@_remember_ior { \c_sys_jobname_str .sct }
      {
        \ior_str_map_inline:Nn \g_@@_remember_ior
          { \@@_remember_read_line:n {##1} }
        \ior_close:N \g_@@_remember_ior
      }
    \seq_map_inline:Nn \g_@@_remember_seq
      {
        \seq_if_exist:cF { g_@@_prev_##1_seq }
          { \seq_new:c { g_@@_prev_##1_seq } }
      }
  }
\cs_new_protected:Npn \@@_remember_read_line:n #1
  {
    \str_if_empty:nF {#1}
      { \@@_remember_read_line:w #1 = = \s_@@_stop }
  }
\cs_new_protected:Npn \@@_remember_read_line:w #1 = #2 = #3 \s_@@_stop
  {
    \str_set_convert:Nnnn \l_@@_remember_name_str {#1} { utf8/hex } { }
    \seq_if_in:NVT \g_@@_remember_seq \l_@@_remember_name_str
      {
        \str_gput_right:Nn \g_@@_remember_old_str { #1 = #2 , }
        \str_set_convert:Nnnn \l_@@_remember_item_str {#2} { utf8/hex } { }
        \seq_if_exist:cF { g_@@_prev_ \l_@@_remember_name_str _seq }
          { \seq_new:c { g_@@_prev_ \l_@@_remember_name_str _seq } }
        \seq_gput_right:cV { g_@@_prev_ \l_@@_remember_name_str _seq }
          \l_@@_remember_item_str
      }
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]
%   {
%     \@@_remember_write:,
%     \@@_remember_write_seq:n,
%     \@@_remember_write_item:n,
%   }
%   The function \myhlc|\@@_remember_write:| writes the file
%   |\jobname.sct| if some \emph{sequence} is remembered: for each
%   one that exists, \myhlc|\@@_remember_write_seq:n| converts its name
%   to hexadecimal digits and \myhlc|\@@_remember_write_item:n| writes a
%   line for each \mymeta{stored content}, also saved in
%   \myhlc|\l_@@_remember_new_str|. If the lines written are not the ones
%   read, the \enquote{warning} |remember-rerun| is issued, otherwise
%   |remember-undefined| if a \mymeta{stored content} was not available.
%    \begin{macrocode}
\cs_new_protected:Npn \@@_remember_write:
  {
    \seq_if_empty:NF \g_@@_remember_seq
      {
        \str_clear:N \l_@@_remember_new_str
        \iow_open:Nn \g_@@_remember_iow { \c_sys_jobname_str .sct }
        \seq_map_function:NN \g_@@_remember_seq \@@_remember_write_seq:n
        \iow_close:N \g_@@_remember_iow
        \str_if_eq:NNTF \g_@@_remember_old_str \l_@@_remember_new_str
          {
            \bool_if:NT \g_@@_remember_pending_bool
              { \msg_warning:nn { scontents } { remember-undefined } }
          }
          { \msg_warning:nn { scontents } { remember-rerun } }
      }
  }
\cs_new_protected:Npn \@@_remember_write_seq:n #1
  {
    \seq_if_exist:cT { g_@@_name_#1_seq }
      {
        \str_set_convert:Nnnn \l_@@_remember_name_str {#1} { } { utf8/hex }
        \seq_map_function:cN { g_@@_name_#1_seq }
          \@@_remember_write_item:n
      }
  }
\cs_new_protected:Npn \@@_remember_write_item:n #1
  {
    \str_set_convert:Nnnn \l_@@_remember_item_str {#1} { } { utf8/hex }
    \iow_now:Ne \g_@@_remember_iow
      { \l_@@_remember_name_str = \l_@@_remember_item_str }
    \str_put_right:Ne \l_@@_remember_new_str
      { \l_@@_remember_name_str = \l_@@_remember_item_str , }
  }
%    \end{macrocode}
% \end{macro}
%
%   The file is read at the beginning of the document and written at the
%   end of it.
%    \begin{macrocode}
\hook_gput_code:nnn { begindocument } { scontents }
  { \@@_remember_read: }
\hook_gput_code:nnn { enddocument } { scontents }
  { \@@_remember_write: }
%</latex>
%    \end{macrocode}
%
% \subsection{The command \cs{newenvsc}}\label{cmd:newenvsc}
%
% The user-level command |\newenvsc| creates a new environment with the
% same behavior as the base environment |scontents|, which is itself
% defined with |\newenvsc| (\S\ref{env:scontents}). It takes a mandatory
% argument, the \mymarg{env name}, and an optional argument with the
% \mymeta{initial keys}. The references to |\begin{scontents}| or
% |\end{scontents}| in this section apply to any environment defined
% with |\newenvsc|.
%
% \subsubsection{Definition of variables for \cs[no-index]{newenvsc}}
%
% \begin{macro}[int]
%   {
%     \l_@@_save_every_body_lines_tl,
%     \l_@@_processed_body_lines_tl,
%     \l_@@_environment_keys_tl,
%     \l_@@_nesting_env_int,
%     \l_@@_nesting_aux_int,
%   }
%   The token list \myhlc|\l_@@_save_every_body_lines_tl| holds the
%   \mymarg{body env} of the environment while it is being read and the
%   token list \myhlc|\l_@@_processed_body_lines_tl| saves it once the
%   environment is closed. The token list
%   \myhlc|\l_@@_environment_keys_tl| saves the \mymeta{keys} passed to the
%   \emph{optional argument} and the integer variables
%   \myhlc|\l_@@_nesting_env_int| and \myhlc|\l_@@_nesting_aux_int| are
%   used to analyze the nesting of the environment.
%    \begin{macrocode}
%<*core>
\tl_new:N  \l_@@_save_every_body_lines_tl
\tl_new:N  \l_@@_processed_body_lines_tl
\tl_new:N  \l_@@_environment_keys_tl
\int_new:N \l_@@_nesting_env_int
\int_new:N \l_@@_nesting_aux_int
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Definition of error messages for \cs[no-index]{newenvsc}}
%
% \begin{macro}[int]{\@@_env_begin_str:n, \@@_env_end_str:n}
%   The functions \myhlc|\@@_env_begin_str:n| and
%   \myhlc|\@@_env_end_str:n| return the start and the end of the
%   environment named by |#1| as they are written in each format:
%   |\begin{#1}| and |\end{#1}| in \LaTeX, |\#1| and |\end#1| in
%   \hologo{plainTeX} and |\start#1| and |\stop#1| in \hologo{ConTeXt}.
%   They are used in the messages of the environments.
%    \begin{macrocode}
\cs_new:Npn \@@_env_begin_str:n #1
  {
    \@@_format_case:nnn
      { \c_backslash_str begin \c_left_brace_str #1 \c_right_brace_str }
      { \c_backslash_str #1 }
      { \c_backslash_str start #1 }
  }
\cs_new:Npn \@@_env_end_str:n #1
  {
    \@@_format_case:nnn
      { \c_backslash_str end \c_left_brace_str #1 \c_right_brace_str }
      { \c_backslash_str end #1 }
      { \c_backslash_str stop #1 }
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{junk-after-begin, env-already-defined}
%   The \enquote{error} |junk-after-begin| is raised when there are
%   characters after the start of the environment or its
%   \emph{optional argument} on the same line and the \enquote{error}
%   |env-already-defined| is
%   raised when |\newenvsc| is used with the name of an environment that
%   already exists.
%    \begin{macrocode}
\msg_new:nnnn { scontents } { junk-after-begin }
  {
    Junk~characters~#1~\msg_line_context: :
    \\ \\
    #2
  }
  {
    Nothing~is~allowed~after~the~start~of~the~environment~on~the~same~
    line.~These~characters~are~ignored.
  }
\msg_new:nnnn { scontents } { env-already-defined }
  { Environment~'#1'~already~defined! }
  {
    You~have~used~\token_to_str:N \newenvsc \c_space_tl
    with~an~environment~that~already~has~a~definition. \\ \\
    The~existing~definition~of~'#1'~will~not~be~altered.
  }
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Definition of messages for \cs[no-index]{newenvsc}}
%
% \begin{macro}[int]{empty-environment, rescanning-text, multiple-begin}
%   The \enquote{warning} |empty-environment| is issued when the
%   environment is empty, the \enquote{warning} |rescanning-text| when
%   there are characters after the end of the environment on the same line
%   and the \enquote{warning} |multiple-begin| when the environment starts
%   more than once on the same line. The start and the end of the
%   environment are written with \myhlc|\@@_env_begin_str:n| and
%   \myhlc|\@@_env_end_str:n|.
%    \begin{macrocode}
\msg_new:nnn { scontents } { empty-environment }
  { Environment~'#1'~is~empty~\msg_line_context:. }
\msg_new:nnn { scontents } { rescanning-text }
  {
    Rescanning~text~'#1'~after~\@@_env_end_str:n {#2}~
    \msg_line_context:.
  }
\msg_new:nnn { scontents } { multiple-begin }
  {
    Multiple~\@@_env_begin_str:n { \l_@@_env_name_tl }~
    \msg_line_context:.
  }
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Definition of keys for \cs[no-index]{newenvsc}}\label{key:newenvsc}
%
% \begin{macro}[int]
%   {
%     write-env,
%     write-out,
%     print-env,
%     store-env,
%     force-eol,
%     overwrite,
%     unknown,
%   }
%   We define the \mymeta{keys} for the environments defined by
%   |\newenvsc|, the unknown \mymeta{keys} are passed to
%   \myhlc|\@@_unknown_keys_env:n| (\S\ref{key:unknown-keys}).
%    \begin{macrocode}
\keys_define:nn { scontents / scontents }
  {
    write-env .code:n           = { \@@_set_write_store:n {#1} },
    write-out .code:n           = { \@@_set_write_out:n {#1} },
    write-env .value_required:n = true,
    write-out .value_required:n = true,
    print-env .meta:nn          = { scontents } { print-env = #1 },
    print-env .default:n        = true,
    store-env .meta:nn          = { scontents } { store-env = #1 },
    force-eol .meta:nn          = { scontents } { force-eol = #1 },
    force-eol .default:n        = true,
    overwrite .meta:nn          = { scontents } { overwrite = #1 },
    overwrite .default:n        = true,
    unknown   .code:n           = { \@@_unknown_keys_env:n {#1} },
  }
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Internal functions for \cs[no-index]{newenvsc}}\label{fun:newenvsc}
%
% \begin{macro}[int]{\@@_grab_opt_arg:w, \@@_grab_opt_arg:n}
%   The function \myhlc|\@@_grab_opt_arg:w| is called with the tokens
%   following |\begin{scontents}| when the next character is a `|[|'. It
%   is defined with \mypkg{ltcmd}\cite{latex2e} to use its delimited
%   argument processor.
%    \begin{macrocode}
\NewDocumentCommand \@@_grab_opt_arg:w { r[] }
  {
    \@@_grab_opt_arg:n {#1}
  }
%    \end{macrocode}
%   The function \myhlc|\@@_grab_opt_arg:n| is called where `\myhlc|^^M|' is
%   active, so \myhlc|\@@_normalise_line_ends:N| replaces the active
%   `\myhlc|^^M|' characters by spaces before setting the \mymeta{keys}.
%    \begin{macrocode}
\cs_new_protected:Npn \@@_grab_opt_arg:n #1
  {
    \tl_set:Nn \l_@@_environment_keys_tl {#1}
    \@@_normalise_line_ends:N \l_@@_environment_keys_tl
    \keys_set:nV { scontents / scontents } \l_@@_environment_keys_tl
    \@@_start_after_option:w
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]
%   {
%     \@@_normalise_line_ends:N,
%     \@@_start_environment:w,
%     \@@_start_after_option:w,
%     \@@_check_line_process:nn,
%     \@@_stop_environment:,
%   }
%   Here `\myhlc|^^I|', `\myhlc|^^L|' and `\myhlc|^^M|' are active characters, so that the
%   end of line can be used as a delimiter and \hologo{TeX} does not
%   remove the space-like characters.
%
%   The function \myhlc|\@@_start_environment:w| checks if the next token
%   after |\begin{scontents}| is a `|[|', in that case
%   \myhlc|\@@_grab_opt_arg:w| processes the \emph{optional argument} and
%   calls \myhlc|\@@_start_after_option:w|. In all cases the function
%   \myhlc|\@@_check_line_process:nn| raises the \enquote{error}
%   |junk-after-begin| if there is something else on the line and then
%   calls \myhlc|\@@_file_tl_write_start:V|, which reads the content of
%   the environment and stores it in a token list or writes it to an
%   \mymeta{external file}.
%
%   At the end of the environment, the function
%   \myhlc|\@@_stop_environment:| calls \myhlc|\@@_file_write_stop:N| and
%   issues the \enquote{warning} |empty-environment| if nothing was
%   stored. This part of the code is adapted from the code of the package
%   \mypkg{xsim}\cite{xsim} by Clemens Niederberger.
%    \begin{macrocode}
\group_begin:
  \char_set_catcode_active:N \^^I
  \char_set_catcode_active:N \^^L
  \char_set_catcode_active:N \^^M
  \cs_new_protected:Npn \@@_normalise_line_ends:N #1
    { \tl_replace_all:Nnn #1 { ^^M } { ~ } }
  \cs_new_protected:Npn \@@_start_environment:w #1 ^^M
    {
      \tl_if_head_is_N_type:nTF {#1}
        {
          \str_if_eq:eeTF { \tl_head:n {#1} } { [ }
            { \@@_grab_opt_arg:w #1 ^^M }
            { \@@_check_line_process:nn { } {#1} }
        }
        { \@@_check_line_process:nn { } {#1} }
    }
  \cs_new_protected:Npn \@@_start_after_option:w #1 ^^M
    { \@@_check_line_process:nn { [...] } {#1} }
  \cs_new_protected:Npn \@@_check_line_process:nn #1 #2
    {
      \tl_if_blank:nF {#2}
        {
          \msg_error:nnee { scontents } { junk-after-begin }
            { after~ \@@_env_begin_str:n { \l_@@_env_name_tl } #1 } {#2}
        }
      \@@_make_control_chars_active:
      \@@_file_tl_write_start:V \l_@@_file_name_tl
    }
  \cs_new_protected:Nn \@@_stop_environment:
    {
      \@@_file_write_stop:N \l_@@_processed_body_lines_tl
      \bool_lazy_and:nnT
        { \l_@@_storing_bool }
        { \tl_if_empty_p:N \l_@@_processed_body_lines_tl }
        {
          \msg_warning:nne { scontents } { empty-environment }
            { \l_@@_env_name_tl }
        }
    }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]
%   {
%     \@@_file_tl_write_start:n,
%     \@@_file_tl_write_start:V,
%     \@@_setup_verb_processor:,
%     \@@_verb_processor_iterate:w,
%     \@@_verb_processor_iterate:nnn,
%     \@@_env_end_function:,
%     \@@_file_write_stop:N,
%     \@@_remove_leading_nl:n,
%     \@@_remove_leading_nl:nn,
%     \@@_remove_leading_nl:w,
%   }
%   This is the main function to collect the \mymarg{body env} of the
%   environment. The function \myhlc|\@@_file_tl_write_start:n| starts a
%   \emph{group}, opens the \mymeta{output file} if necessary, sets the
%   \emph{verbatim catcodes} and then issues `\myhlc|^^M|', set equal to
%   \myhlc|\@@_ret:w|, to read the \mymarg{body env} line by line until
%   its end. Each line read is appended to the output token list after an
%   active `\myhlc|^^J|' and written to the \mymeta{output file}, if any.
%
%   The function \myhlc|\@@_setup_verb_processor:| defines
%   \myhlc|\@@_verb_processor_iterate:w|, delimited by the end of the
%   current environment, and \myhlc|\@@_verb_processor_iterate:nnn|
%   decides if the line is a nested |\end{scontents}| or the end of the
%   environment, in which case \myhlc|\@@_env_end_function:| leaves the
%   closing command for the current format and the characters after it
%   are rescanned with the \enquote{warning} |rescanning-text|.
%
%   At the end of the environment, the function
%   \myhlc|\@@_file_write_stop:N| closes the \mymeta{output file}, if it
%   was opened, and smuggles the output token list out of the group. The
%   leading `\myhlc|^^J|' is removed with \myhlc|\@@_remove_leading_nl:n|, which
%   expects an active `\myhlc|^^J|' at the head of the token list, otherwise a
%   low level \hologo{TeX} \enquote{error} is raised.
%    \begin{macrocode}
  \cs_new_protected:Npn \@@_file_tl_write_start:n #1
    {
      \group_begin:
        \@@_file_if_writable:nTF {#1}
          {
            \bool_set_true:N \l_@@_writable_bool
            \iow_open:Nn \l_@@_file_write_iow {#1}
          }
          { \bool_set_false:N \l_@@_writable_bool }
        \tl_clear:N \l_@@_save_every_body_lines_tl
        \seq_map_function:NN \l_char_special_seq \char_set_catcode_other:N
        \int_step_function:nnnN { 128 } { 1 } { 255 } \char_set_catcode_letter:n
        \cs_set_protected:Npe \@@_ret:w ##1 ^^M
          {
            \exp_not:N \@@_verb_processor_iterate:w
            ##1 \c_@@_end_env_tl
                \c_@@_end_env_tl
                \exp_not:N \q_@@_stop
          }
        \@@_make_control_chars_active:
        \@@_ret:w
    }
  \cs_new_protected:Nn \@@_setup_verb_processor:
    {
      \use:e
        {
          \cs_set_protected:Npn \exp_not:N \@@_verb_processor_iterate:w
            ##1 \c_@@_end_env_tl
            ##2 \c_@@_end_env_tl
            ##3 \exp_not:N \q_@@_stop
        }   { \@@_verb_processor_iterate:nnn {##1} {##2} {##3} }
    }
  \cs_new_protected:Npn \@@_verb_processor_iterate:nnn #1 #2 #3
    {
      \tl_if_blank:nTF {#3}
        {
          \@@_analyse_nesting:n {#1}
          \@@_verb_processor_output:n {#1}
        }
        {
          \@@_if_nested:TF
            {
              \@@_nesting_decr:
              \@@_verb_processor_output:e
                { \exp_not:n {#1} \c_@@_end_env_tl \exp_not:n {#2} }
            }
            {
              \tl_if_blank:nF {#1}
                { \@@_verb_processor_output:n {#1} }
              \cs_set_protected:Npe \@@_ret:w
                {
                  \@@_env_end_function:
                  \bool_lazy_or:nnF
                    { \tl_if_blank_p:n {#2} }
                    { \str_if_eq_p:ee {#2} { \c_percent_str } }
                    {
                      \str_if_eq:VnF \c_@@_hidden_space_str {#2}
                        {
                          \msg_warning:nnnn { scontents } { rescanning-text }
                            {#2} { \tl_use:N \l_@@_env_name_tl }
                        }
                      \tl_retokenize:n {#2}
                    }
                }
              \char_set_active_eq:NN ^^M \@@_ret:w
            }
        }
      ^^M
    }
  \cs_new:Nn \@@_env_end_function:
    {
      \@@_format_case:nnn
        { \exp_not:N \end { \if_false: } \fi: }
        { \exp_after:w \exp_not:N \cs:w end }
        { \exp_after:w \exp_not:N \cs:w stop }
      \tl_use:N \l_@@_env_name_tl
      \@@_format_case:nnn
        { \if_false: { \fi: } }
        { \cs_end: }
        { \cs_end: }
    }
  \cs_new_protected:Npn \@@_file_write_stop:N #1
    {
      \bool_if:NT \l_@@_writable_bool
        { \iow_close:N \l_@@_file_write_iow }
      \use:e
        {
          \group_end:
          \bool_if:NT \l_@@_storing_bool
            {
              \tl_set:Nn \exp_not:N #1
                {
                  \exp_args:NV
                    \@@_remove_leading_nl:n \l_@@_save_every_body_lines_tl
                }
            }
        }
    }
  \cs_new:Npn \@@_remove_leading_nl:n #1
    {
      \tl_if_head_is_N_type:nTF {#1}
        {
          \exp_args:Nf
            \@@_remove_leading_nl:nn
              { \tl_head:n {#1} } {#1}
        }
        { \exp_not:n {#1} }
    }
  \cs_new:Npn \@@_remove_leading_nl:nn #1 #2
    {
      \token_if_eq_meaning:NNTF ^^J #1
        { \exp_not:o { \@@_remove_leading_nl:w #2 } }
        { \exp_not:n {#2} }
    }
  \cs_new:Npn \@@_remove_leading_nl:w ^^J { }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{\@@_verb_processor_output:n, \@@_verb_processor_output:e}
%   The function \myhlc|\@@_verb_processor_output:n| does the output of
%   each line read, to the token list and to the \mymeta{output file},
%   according to the booleans \myhlc|\l_@@_writable_bool| and
%   \myhlc|\l_@@_storing_bool|.
%    \begin{macrocode}
  \cs_new_protected:Npn \@@_verb_processor_output:n #1
    {
      \bool_if:NT \l_@@_writable_bool
        { \iow_now:Nn \l_@@_file_write_iow {#1} }
      \bool_if:NT \l_@@_storing_bool
        { \tl_put_right:Nn \l_@@_save_every_body_lines_tl { ^^J #1 } }
    }
\group_end:
\cs_generate_variant:Nn \@@_verb_processor_output:n { e }
\cs_generate_variant:Nn \@@_file_tl_write_start:n { V }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]
%   {
%     \@@_analyse_nesting:n,
%     \@@_nesting_incr:,
%     \@@_nesting_decr:,
%   }
% \begin{macro}[int,TF]{\@@_if_nested:}
%   The function \myhlc|\@@_analyse_nesting:n| scans the nested
%   |\begin{scontents}| in a line and steps the counter
%   \myhlc|\l_@@_nesting_env_int|, issuing the \enquote{warning}
%   |multiple-begin| if there is more than one. The conditional
%   \myhlc|\@@_if_nested:TF| tests if we are in a nested environment and
%   \myhlc|\@@_nesting_decr:| reduces the nesting level when an
%   |\end{scontents}| is found.
%    \begin{macrocode}
\cs_new_protected:Npn \@@_analyse_nesting:n #1
  {
    \int_zero:N \l_@@_nesting_aux_int
    \@@_analyse_nesting_format:n {#1}
    \int_compare:nNnT { \l_@@_nesting_aux_int } > { 1 }
      { \msg_warning:nn { scontents } { multiple-begin } }
  }
\cs_new_protected:Nn \@@_nesting_incr:
  {
    \int_incr:N \l_@@_nesting_env_int
    \int_incr:N \l_@@_nesting_aux_int
  }
\cs_new_protected:Nn \@@_nesting_decr:
  {
    \int_decr:N \l_@@_nesting_env_int
  }
\prg_new_protected_conditional:Npnn \@@_if_nested: { TF }
  {
    \int_compare:nNnTF { \l_@@_nesting_env_int } > { \c_zero_int }
      { \prg_return_true: }
      { \prg_return_false: }
  }
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{important}*
%   Multiple |\end{scontents}| on the same line are NOT supported.
% \end{important}
%
% \begin{macro}[int]
%   {
%     \@@_analyse_nesting_latex:n,
%     \@@_analyse_nesting_latex:w,
%     \@@_analyse_nesting_generic:nn,
%     \@@_analyse_nesting_generic:w,
%     \@@_analyse_nesting_generic_process:nn,
%     \@@_define_generic_nesting_function:n,
%     \@@_analyse_nesting_format:n,
%   }
%   In \LaTeX{} the environments start with |\begin{<env>}| and no `|}|'
%   can appear inside |<env>|, so a macro delimited by `|}|' is enough to
%   find the nested |\begin{scontents}|.
%    \begin{macrocode}
\use:e
  {
    \cs_new_protected:Npn \exp_not:N \@@_analyse_nesting_latex:w #1
      \c_backslash_str begin \c_left_brace_str #2 \c_right_brace_str
  }   {
        \@@_tl_if_head_is_q_mark:nTF {#2}
          { \@@_use_none_delimit_by_q_stop:w }
          {
            \str_if_eq:VnT \l_@@_env_name_tl {#2}
              { \@@_nesting_incr: }
            \@@_analyse_nesting_latex:w
          }
      }
\cs_new_protected:Npe \@@_analyse_nesting_latex:n #1
  {
    \@@_analyse_nesting_latex:w #1
      \c_backslash_str begin
        \c_left_brace_str \exp_not:N \q_@@_mark \c_right_brace_str
    \exp_not:N \q_@@_stop
  }
%    \end{macrocode}
%   In the other formats there is no \enquote{end anchor} to delimit the
%   name of the environment, so we search for the whole command that
%   starts the environment, |\scontents| or |\startscontents|.
%    \begin{macrocode}
\cs_new_protected:Npn \@@_analyse_nesting_generic_process:nn #1 #2
  {
    \tl_if_head_is_N_type:nTF {#2}
      {
        \@@_tl_if_head_is_q_mark:nF {#2}
          {
            \@@_nesting_incr:
            \@@_analyse_nesting_generic:w #2 \q_@@_stop
          }
      }
      { \@@_analyse_nesting_generic:w #2 \q_@@_stop }
  }
\cs_new_protected:Npn \@@_analyse_nesting_generic:nn #1 #2
  {
    \@@_define_generic_nesting_function:n {#1}
    \use:e
      {
        \exp_not:N \@@_analyse_nesting_generic:w #2
          \c_backslash_str #1 \tl_use:N \l_@@_env_name_tl
            \exp_not:N \q_@@_mark \exp_not:N \q_@@_stop
      }
  }
\cs_new_protected:Npn \@@_define_generic_nesting_function:n #1
  {
    \use:e
      {
        \cs_set_protected:Npn \exp_not:N \@@_analyse_nesting_generic:w ##1
          \c_backslash_str #1 \tl_use:N \l_@@_env_name_tl
            ##2 \exp_not:N \q_@@_stop
      }   { \@@_analyse_nesting_generic_process:nn {##1} {##2} }
  }
%</core>
%    \end{macrocode}
%   The function \myhlc|\@@_analyse_nesting_format:n| uses the version
%   for the current format.
%    \begin{macrocode}
%<*loader>
%<latex>\cs_new_eq:NN \@@_analyse_nesting_format:n
%<latex>  \@@_analyse_nesting_latex:n
%<!latex>\cs_new_protected:Npn \@@_analyse_nesting_format:n
%<plain>  { \@@_analyse_nesting_generic:nn { } }
%<context>  { \@@_analyse_nesting_generic:nn { start } }
%</loader>
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{\@@_generic_begin:, \@@_generic_end:}
%   The function \myhlc|\@@_generic_begin:| leaves the `\myhlc|^^M|' character
%   active and calls \myhlc|\@@_start_environment:w|. The function
%   \myhlc|\@@_generic_end:| calls \myhlc|\@@_stop_environment:| and then
%   \myhlc|\@@_finish_storing:NNN|, which stores the \mymarg{body env} in
%   the \emph{sequence} and prints it if the \mykey{print-env} key is
%   active (\S\ref{fun:sequences}).
%    \begin{macrocode}
%<*core>
\cs_new_protected:Npn \@@_generic_begin:
  {
    \char_set_catcode_active:N \^^M
    \@@_start_environment:w
  }
\cs_new_protected:Npn \@@_generic_end:
  {
    \@@_stop_environment:
    \@@_finish_storing:NNN
      \l_@@_processed_body_lines_tl
      \l_@@_name_seq_env_tl
      \l_@@_print_env_bool
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{\@@_setting_env:nn, \@@_define_env:nnn}
%   The function \myhlc|\@@_setting_env:nn| receives the \emph{name} of
%   the environment in |#1| and the \mymeta{initial keys} in |#2|. It
%   creates the functions \cs[no-index]{@@_\#1_begin:} and
%   \cs[no-index]{@@_\#1_end:}, which set \myhlc|\l_@@_env_name_tl| and
%   the \mymeta{initial keys} and call \myhlc|\@@_generic_begin:| and
%   \myhlc|\@@_generic_end:|, and passes them to
%   \myhlc|\@@_define_env:nnn|.
%    \begin{macrocode}
\cs_new_protected:Npn \@@_setting_env:nn #1 #2
  {
    \cs_new_protected:cpn { @@_#1_begin: }
      {
        \tl_set:Nn \l_@@_env_name_tl {#1}
        \tl_set:Nn \l_@@_cmd_name_tl { newenvsc }
        \keys_set:nn { scontents } {#2}
        \@@_setup_verb_processor:
        \@@_generic_begin:
      }
    \cs_new_protected:cpn { @@_#1_end: }
      { \@@_generic_end: }
    \exp_args:Nooo \@@_define_env:nnn
      { \tl_to_str:n {#1} }
      { \cs:w @@_#1_begin: \cs_end: }
      { \cs:w @@_#1_end: \cs_end: }
  }
%</core>
%    \end{macrocode}
%   The function \myhlc|\@@_define_env:nnn| creates the environment for
%   \hologo{LaTeX}, \hologo{plainTeX} and \hologo{ConTeXt}.
%    \begin{macrocode}
%<*loader>
\cs_new_protected:Npn \@@_define_env:nnn #1 #2 #3
  {
%<latex|plain>    \NewDocumentEnvironment {#1} { }
%<context>    \cs_new_protected:cpn { start #1 }
      {
%<!latex>        \group_begin:
          #2
      }
%<context>    \cs_new_protected:cpn { stop #1 }
      {
          #3
%<!latex>        \group_end:
      }
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\newenvsc}
%   Defines the user command \ics*{newenvsc} for \hologo{LaTeX},
%   \hologo{plainTeX} and \hologo{ConTeXt}, raising the \enquote{error}
%   |env-already-defined| if the environment exists.
%    \begin{macrocode}
\NewDocumentCommand \newenvsc { m O{} }
  {
%<latex|plain>    \cs_if_exist:cTF {#1}
%<context>    \cs_if_exist:cTF { start #1 }
      { \msg_error:nnn { scontents } { env-already-defined } {#1} }
      { \@@_setting_env:nn {#1} {#2} }
  }
%</loader>
%    \end{macrocode}
% \end{macro}
%
% \subsection{The environment \env{scontents}}\label{env:scontents}
%
% \begin{macro}
%   {
%     scontents,
%     \scontents,
%     \endscontents,
%     \startscontents,
%     \stopscontents,
%   }
%   The base environment |scontents| is defined with |\newenvsc|, in
%   \hologo{plainTeX} it is |\scontents|\,\dots\,|\endscontents| and in
%   \hologo{ConTeXt} |\startscontents|\,\dots\,|\stopscontents|.
%    \begin{macrocode}
%<*loader>
\newenvsc{scontents}
%</loader>
%    \end{macrocode}
% \end{macro}
%
% \subsection{The environment \env{verbatimsc}}\label{env:verbatimsc}
%
% The |verbatimsc| environment is a customized version of the standard
% \myenv[no-index]{verbatim} environment of \hologo{LaTeX} used by
% |\typestored| (\S\ref{cmd:typestored}). For \hologo{plainTeX} and
% \hologo{ConTeXt} we must add some additional functions.
%
% \subsubsection{Definition of variables for \env{verbatimsc}}
%
% \begin{macro}[int]{\l_@@_plain_bool}
%   The boolean variable \myhlc|\l_@@_plain_bool| is used in the
%   \hologo{plainTeX} version of the |verbatimsc| environment.
%    \begin{macrocode}
%<*plain>
\bool_new:N \l_@@_plain_bool
%</plain>
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Internal functions for \env{verbatimsc}}
%
% \begin{macro}[int]{\dospecials}
%   The \myenv[no-index]{verbatim} environment requires
%   \myhlc|\dospecials|. In case it does not exist when
%   \mypkg*[no-index]{scontents} is loaded, we define it with
%   \myhlc|\l_char_special_seq|.
%    \begin{macrocode}
%<*!latex>
\cs_if_exist:NF \dospecials
  {
    \cs_new:Npn \dospecials
      { \seq_map_function:NN \l_char_special_seq \do }
  }
%</!latex>
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{\@@_xverb:w, \@@_xverb:}
%   The environment |verbatimsc| needs to find literally its end, this is
%   done by \myhlc|\@@_xverb:w|, delimited by
%   \myhlc|\g_@@_end_verbatimsc_tl|, for \hologo{plainTeX} and \LaTeX.
%   The function \myhlc|\@@_xverb:| makes the \texttt{TAB} character
%   active, equal to \myhlc|\@@_tabs_to_spaces:|, and calls
%   \myhlc|\@@_xverb:w|.
%    \begin{macrocode}
%<*loader>
%<*!context>
\use:e
  {
    \cs_new_protected:Npn \exp_not:N \@@_xverb:w
      #1 \g_@@_end_verbatimsc_tl
%<latex>      { #1 \exp_not:N \end{verbatimsc} }
%<plain>      { #1 \exp_not:N \endverbatimsc }
  }
%</!context>
%</loader>
%<*core>
\cs_new_protected:Nn \@@_xverb:
  {
    \char_set_catcode_active:n { 9 }
    \char_set_active_eq:nN { 9 } \@@_tabs_to_spaces:
    \@@_xverb:w
  }
%</core>
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{\hologo{plainTeX} version of \texttt{verbatimsc}}
%
% \begin{macro}[int]
%   {
%     \@@_verbatimsc_aux:,
%     \@@_nolig_list:,
%     \@@_vobeyspaces:,
%     \@@_xobeysp:,
%   }
%   In \hologo{plainTeX} we emulate the \myenv[no-index]{verbatim}
%   environment of \LaTeX.
%    \begin{macrocode}
%<*plain>
\cs_new_protected:Nn \@@_verbatimsc_aux:
  {
    \skip_vertical:N \parskip
    \dim_zero:N \parindent
    \skip_set:Nn \parfillskip { 0pt plus 1fil }
    \skip_set:Nn \parskip { 0pt plus0pt minus0pt }
    \tex_par:D
    \bool_set_false:N \l_@@_plain_bool
    \cs_set:Npn \par
      {
        \bool_if:NTF \l_@@_plain_bool
          {
            \mode_leave_vertical:
            \null
            \tex_par:D
            \penalty \interlinepenalty
          }
          {
            \bool_set_true:N \l_@@_plain_bool
            \mode_if_horizontal:T
              { \tex_par:D \penalty \interlinepenalty }
          }
      }
    \cs_set_eq:NN \do \char_set_catcode_other:N
    \dospecials \obeylines
    \tl_use:N \l_@@_verb_font_tl
    \cs_set_eq:NN \do \@@_do_noligs:N
    \@@_nolig_list:
    \tex_everypar:D \exp_after:w
      { \tex_the:D \tex_everypar:D \tex_unpenalty:D }
  }
\cs_new_protected:Nn \@@_nolig_list:
  { \do\`\do\<\do\>\do\,\do\'\do\- }
\cs_new_protected:Nn \@@_vobeyspaces:
  { \@@_set_active_eq:NN \  \@@_xobeysp: }
\cs_new_protected:Nn \@@_xobeysp:
  { \mode_leave_vertical: \nobreak \ }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{\@@_verbatimsc_line:w}
%   The function \myhlc|\@@_verbatimsc_line:w| discards the rest of the
%   line of |\verbatimsc| up to the active end of line. When |\typestored|
%   rescans the \mymeta{stored content} a space follows |\verbatimsc| and,
%   once the spaces are active, it would start an empty line at the top of
%   the environment.
%    \begin{macrocode}
\group_begin:
  \char_set_catcode_active:N \^^M
  \cs_new_protected:Npn \@@_verbatimsc_line:w #1 ^^M
    {
      \@@_verbatimsc_aux: \frenchspacing \@@_vobeyspaces:
      \@@_xverb:
    }
\group_end:
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\verbatimsc, \endverbatimsc}
%   Defines the environment \myenv*{verbatimsc} for \hologo{plainTeX}.
%   As in the environments of \hologo{ConTeXt}, the rest of the line of
%   |\verbatimsc| is ignored.
%    \begin{macrocode}
\cs_new_protected:Npn \verbatimsc
  {
    \group_begin:
      \char_set_catcode_active:N \^^M
      \@@_verbatimsc_line:w
  }
\cs_new_protected:Npn \endverbatimsc
  { \group_end: }
%</plain>
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{\hologo{ConTeXt} version of \texttt{verbatimsc}}
%
% \begin{macro}{\startverbatimsc, \stopverbatimsc}
%   In \hologo{ConTeXt} we use its own tool \myhlc|\definetyping|.
%    \begin{macrocode}
%<*loader>
%<context>\definetyping[verbatimsc]
%</loader>
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{\hologo{LaTeX} version of \texttt{verbatimsc}}
%
% \begin{macro}[int]{\@@_verbatimsc_instance:}
%   To be compatible with \emph{tagged} \texttt{PDF} the environment
%   |verbatimsc| is defined with the \mypkg{xtemplate}\cite{latex2e}
%   module of the \LaTeX{} kernel and the \texttt{blocks-code} of
%   \mypkg{latex-lab}\cite{latexlab}. The function
%   \myhlc|\@@_verbatimsc_instance:| declares the instance of
%   \texttt{blockenv} used by the environment, only once at the beginning
%   of the document and only if \emph{tagged} \texttt{PDF} is active.
%   This code is adapted from the answer of Ulrike Fischer to
%   \href{https://tex.stackexchange.com/a/741178/7832}{New verbatim environment with block code (tagged-pdf)}.
%    \begin{macrocode}
%<*loader>
%<*latex>
\cs_new_protected:Nn \@@_verbatimsc_instance:
  {
    \DeclareInstance{blockenv}{verbatimsc}{std}
      {
        name                   = verbatimsc,
        tag-name               = \UseStructureName{block/verbatim},
        tagging-recipe         = standard,
        tagging-suppress-paras = true,
        block-instance         = verbatim,
        para-instance          = justify,
        final-code             = \legacyverbatimsetup{invisible},
      }
  }
\hook_gput_code:nnn { begindocument } { scontents }
  {
    \IfDocumentMetadataTF { \@@_verbatimsc_instance: } { }
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{verbatimsc}
%   Defines the environment \myenv*{verbatimsc} for \LaTeX. The
%   |\endverbatim| in the second argument is only needed for
%   compatibility with the \mypkg{verbatim}\cite{verbatim} package.
%    \begin{macrocode}
\NewDocumentEnvironment { verbatimsc } { }
  {
    \IfDocumentMetadataTF
      {
        \UseInstance{blockenv}{verbatimsc}{}
        \@setupverbinvisiblespace\frenchspacing\@vobeyspaces
        \@@_xverb:
      }
      {
        \cs_set_eq:cN { @xverbatim } \@@_xverb:
        \verbatim
      }
  }
  {
    \IfDocumentMetadataTF
      {
        \BlockEnvEnd
      }
      { \endverbatim }
  }
%</latex>
%</loader>
%    \end{macrocode}
% \end{macro}
%
% \subsection{The command \cs{Scontents}}\label{cmd:Scontents}
%
% The user-level command |\Scontents| stores its \mymarg{argument} in a
% \emph{sequence}. It takes an optional \emph{starred argument}, an
% optional argument with the \mymeta{keys} and the \mymarg{argument},
% which is read in standard mode or, with the \emph{starred argument},
% under the \emph{verbatim catcode} regimen. It is adapted from code by
% Ulrich Diez in \href{https://tex.stackexchange.com/a/472044/7832}{Stringify
% input - \textbackslash string on token list} and code by user
% \texttt{@siracusa} in
% \href{https://tex.stackexchange.com/a/500281/7832}{Convert a macro from Latex2e to expl3}.
%
% \subsubsection{Definition of variables for \cs[no-index]{Scontents}}
%
% \begin{macro}[int]{\l_@@_Scontents_arg_tl}
%   The token list \myhlc|\l_@@_Scontents_arg_tl| saves the
%   \mymarg{argument} passed to |\Scontents|.
%    \begin{macrocode}
%<*core>
\tl_new:N \l_@@_Scontents_arg_tl
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Definition of messages for \cs[no-index]{Scontents}}
%
% \begin{macro}[int]{empty-argument-command}
%   The \enquote{warning} |empty-argument-command| is issued when the
%   \mymarg{argument} of |\Scontents| is empty.
%    \begin{macrocode}
\msg_new:nnn { scontents } { empty-argument-command }
  { Empty~argument~for~\c_backslash_str Scontents~\msg_line_context:. }
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Definition of keys for \cs[no-index]{Scontents}}\label{key:Scontents}
%
% \begin{macro}[int]
%   {
%     write-cmd,
%     write-out,
%     print-cmd,
%     store-cmd,
%     force-eol,
%     overwrite,
%     unknown,
%   }
%   We define the \mymeta{keys} for both versions of |\Scontents|, the
%   unknown \mymeta{keys} are passed to \myhlc|\@@_unknown_keys_cmd:n|
%   (\S\ref{key:unknown-keys}).
%    \begin{macrocode}
\keys_define:nn { scontents / Scontents }
  {
    write-cmd .code:n           = { \@@_set_write_store:n {#1} },
    write-out .code:n           = { \@@_set_write_out:n {#1} },
    write-cmd .value_required:n = true,
    write-out .value_required:n = true,
    print-cmd .meta:nn          = { scontents } { print-cmd = #1 },
    print-cmd .default:n        = true,
    store-cmd .meta:nn          = { scontents } { store-cmd = #1 },
    force-eol .meta:nn          = { scontents } { force-eol = #1 },
    force-eol .default:n        = true,
    overwrite .meta:nn          = { scontents } { overwrite = #1 },
    overwrite .default:n        = true,
    unknown   .code:n           = { \@@_unknown_keys_cmd:n {#1} },
  }
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Internal functions for \cs[no-index]{Scontents}}
%
% \begin{macro}[int]{\@@_Scontents_code:nn}
%   The function \myhlc|\@@_Scontents_code:nn| executes
%   \myhlc|\@@_bsphack:|, opens a group, sets the \mymeta{keys} passed in
%   |#2| and leaves the \texttt{TAB} character active. With the
%   \emph{starred argument} passed in |#1| it calls
%   \myhlc|\@@_Scontents_verb_arg:w|, otherwise
%   \myhlc|\@@_Scontents_norm_arg:n|.
%    \begin{macrocode}
\cs_new_protected:Npn \@@_Scontents_code:nn #1 #2
  {
    \@@_bsphack:
    \group_begin:
      \keys_set:nn { scontents / Scontents } {#2}
      \char_set_catcode_active:n { 9 }
      \bool_if:NTF #1
        { \@@_Scontents_verb_arg:w }
        { \@@_Scontents_norm_arg:n }
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{\@@_Scontents_verb_arg:w}
%   The function \myhlc|\@@_Scontents_verb_arg:w| saves the
%   \mymarg{argument} under the \emph{verbatim catcode} regimen, using a
%   |v|-type argument of \mypkg{ltcmd}, in \myhlc|\l_@@_Scontents_arg_tl|
%   and replaces every `\myhlc|^^M|' and |\obeyedline|, added in \hologo{LaTeX}
%   release 2024-06-01, by `\myhlc|^^J|'. The command |\obeyedline| is redefined
%   with |\RenewDocumentCommand| because it can be modified by the user,
%   which would return a low-level error.
%    \begin{macrocode}
\NewDocumentCommand \@@_Scontents_verb_arg:w { +v }
  {
    \tl_set:Nn \l_@@_Scontents_arg_tl {#1}
    \cs_if_exist:NT \obeyedline
      {
        \RenewDocumentCommand \obeyedline { } { \iow_char:N \^^M }
        \tl_replace_all:Nee \l_@@_Scontents_arg_tl
          { \obeyedline } { \iow_char:N \^^M }
      }
    \tl_replace_all:NeV \l_@@_Scontents_arg_tl
      { \iow_char:N \^^M } \c_@@_newline_tl
    \@@_Scontents_finish:
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{\@@_Scontents_norm_arg:n}
%   The function \myhlc|\@@_Scontents_norm_arg:n| saves the
%   \mymarg{argument} read in the \emph{standard catcode} regimen.
%    \begin{macrocode}
\cs_new_protected:Npn \@@_Scontents_norm_arg:n #1
  {
    \tl_set:Nn \l_@@_Scontents_arg_tl {#1}
    \@@_Scontents_finish:
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{\@@_Scontents_finish:}
%   The function \myhlc|\@@_Scontents_finish:| issues the
%   \enquote{warning} |empty-argument-command| if the \mymarg{argument} is
%   empty, writes it with \myhlc|\@@_file_write_cmd:VV| for the
%   \mykey{write-out} and \mykey{write-cmd} keys and stores and prints it
%   with \myhlc|\@@_finish_storing:NNN|. Finally it closes the group and
%   runs \myhlc|\@@_esphack:| if the \mykey{print-cmd} key is not active.
%    \begin{macrocode}
\cs_new_protected:Nn \@@_Scontents_finish:
  {
    \tl_if_empty:NT \l_@@_Scontents_arg_tl
      { \msg_warning:nn { scontents } { empty-argument-command } }
    \@@_file_write_cmd:VV \l_@@_file_name_tl \l_@@_Scontents_arg_tl
    \@@_finish_storing:NNN
      \l_@@_Scontents_arg_tl \l_@@_name_seq_cmd_tl \l_@@_print_cmd_bool
    \use:e
      {
        \group_end:
        \bool_if:NF \l_@@_print_cmd_bool { \@@_esphack: }
      }
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\Scontents}
%   Defines the user command \ics*{Scontents}.
%    \begin{macrocode}
\NewDocumentCommand \Scontents { !s !O{} }
  {
    \tl_set:Nn \l_@@_cmd_name_tl { Scontents }
    \@@_Scontents_code:nn {#1} {#2}
  }
%    \end{macrocode}
% \end{macro}
%
% \subsection{The command \cs{getstored}}\label{cmd:getstored}
%
% The user-level command |\getstored| takes an optional argument with the
% \mymeta{index}, the last \mymeta{stored content} by default, and a
% mandatory argument with the \mymarg{seq name}. It is robust.
%
% \subsubsection{Internal functions for \cs[no-index]{getstored}}
%
% \begin{macro}[int]{\@@_getstored:nn}
%   The function \myhlc|\@@_getstored:nn| rescans with
%   \myhlc|\tl_retokenize:e| the \mymeta{stored content} at the
%   \mymeta{index} passed in |#1| in the \emph{sequence} named by |#2|,
%   given by \myhlc|\@@_getfrom_seq:nn| (\S\ref{fun:sequences}), unless
%   it is not available yet in a remembered \emph{sequence}
%   (\S\ref{subsec:remember}).
%    \begin{macrocode}
\cs_new_protected:Npn \@@_getstored:nn #1 #2
  {
    \@@_if_pending:neF {#2} { \int_eval:n {#1} }
      {
        \tl_retokenize:e
          {
            \@@_getfrom_seq:nn {#1} {#2}
          }
      }
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\getstored}
%   Defines the user command \ics*{getstored}.
%    \begin{macrocode}
\NewDocumentCommand \getstored { O{-1} m }
  {
    \@@_getstored:nn {#1} {#2}
  }
%    \end{macrocode}
% \end{macro}
%
% \subsection{The command \cs{foreachsc}}\label{cmd:foreachsc}
%
% The user-level command |\foreachsc| runs |\getstored| on the
% \mymeta{stored contents} of a \emph{sequence}. It takes an optional
% argument with the \mymeta{keys} and a mandatory argument with the
% \mymarg{seq name}, raising the \enquote{error} |undefined-storage| if
% the \emph{sequence} does not exist.
%
% \subsubsection{Definition of variables for \cs[no-index]{foreachsc}}
%
% \begin{macro}[int]
%   {
%     \l_@@_foreachsc_arg_tl,
%     \l_@@_foreach_print_seq,
%     \g_@@_foreach_exec_tl,
%     \l_@@_foreach_before_tl,
%     \l_@@_foreach_before_bool,
%     \l_@@_foreach_after_tl,
%     \l_@@_foreach_after_bool,
%     \l_@@_foreach_start_int,
%     \l_@@_foreach_step_int,
%     \l_@@_foreach_stop_int,
%     \l_@@_foreach_stop_bool,
%     \l_@@_foreach_wrapper_bool,
%     \l_@@_foreach_body_tl,
%     \l_@@_foreach_cmd_tl,
%   }
%   The token list \myhlc|\l_@@_foreachsc_arg_tl| saves the
%   \mymarg{seq name}, the sequence \myhlc|\l_@@_foreach_print_seq|
%   collects the code for each \mymeta{stored content}, built in the token
%   list \myhlc|\l_@@_foreach_body_tl|, and the token list
%   \myhlc|\g_@@_foreach_exec_tl| executes it outside the group. The
%   token list \myhlc|\l_@@_foreach_cmd_tl| saves the command executed on
%   each \mymeta{stored content}, |\getstored| by default. The other
%   variables are set by the \mymeta{keys} of |\foreachsc|.
%    \begin{macrocode}
\tl_new:N   \l_@@_foreachsc_arg_tl
\seq_new:N  \l_@@_foreach_print_seq
\tl_new:N   \g_@@_foreach_exec_tl
\tl_new:N   \l_@@_foreach_before_tl
\bool_new:N \l_@@_foreach_before_bool
\tl_new:N   \l_@@_foreach_after_tl
\bool_new:N \l_@@_foreach_after_bool
\int_new:N  \l_@@_foreach_start_int
\int_new:N  \l_@@_foreach_step_int
\int_new:N  \l_@@_foreach_stop_int
\bool_new:N \l_@@_foreach_stop_bool
\bool_new:N \l_@@_foreach_wrapper_bool
\tl_new:N   \l_@@_foreach_body_tl
\tl_new:N   \l_@@_foreach_cmd_tl
\tl_set:Nn  \l_@@_foreach_cmd_tl { \getstored }
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Definition of keys for \cs[no-index]{foreachsc}}\label{key:foreachsc}
%
% \begin{macro}[int]
%   {
%     before,
%     after,
%     start,
%     stop,
%     step,
%     wrapper,
%     sep,
%     unknown,
%   }
%   We define the \mymeta{keys} for |\foreachsc|, the keys \mykey{start},
%   \mykey{step} and \mykey{stop} use \myhlc|\@@_set_positive_int:Nnn|
%   (\S\ref{key:package}) and the unknown \mymeta{keys} are passed to
%   \myhlc|\@@_unknown_keys_cmd:n| (\S\ref{key:unknown-keys}).
%    \begin{macrocode}
\keys_define:nn { scontents / foreachsc }
  {
    before  .code:n           = {
                                  \bool_set_true:N \l_@@_foreach_before_bool
                                  \tl_set:Nn \l_@@_foreach_before_tl {#1}
                                },
    before  .value_required:n = true,
    after   .code:n           = {
                                  \bool_set_true:N \l_@@_foreach_after_bool
                                  \tl_set:Nn \l_@@_foreach_after_tl {#1}
                                },
    after   .value_required:n = true,
    start   .code:n           = {
                                  \@@_set_positive_int:Nnn
                                    \l_@@_foreach_start_int { start } {#1}
                                },
    start   .value_required:n = true,
    start   .initial:n        = 1,
    stop    .code:n           = {
                                  \@@_set_positive_int:Nnn
                                    \l_@@_foreach_stop_int { stop } {#1}
                                  \bool_set:Nn \l_@@_foreach_stop_bool
                                    {
                                      \int_compare_p:nNn
                                        { \l_@@_foreach_stop_int } > { 0 }
                                    }
                                },
    stop    .value_required:n = true,
    step    .code:n           = {
                                  \@@_set_positive_int:Nnn
                                    \l_@@_foreach_step_int { step } {#1}
                                },
    step    .value_required:n = true,
    step    .initial:n        = 1,
    wrapper .code:n           = {
                                  \bool_set_true:N \l_@@_foreach_wrapper_bool
                                  \cs_set_protected:Npn
                                    \@@_foreach_wrapper:n ##1 {#1}
                                },
    wrapper .value_required:n = true,
    sep     .tl_set:N         = \l_@@_foreach_sep_tl,
    sep     .initial:n        = { },
    sep     .value_required:n = true,
    unknown .code:n           = { \@@_unknown_keys_cmd:n {#1} },
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{getstored, typestored, meaningsc}
%   The \mymeta{keys} \mykey{getstored}, \mykey{typestored} and
%   \mykey{meaningsc} set the command saved in
%   \myhlc|\l_@@_foreach_cmd_tl|.
%    \begin{macrocode}
\keys_define:nn { scontents / foreachsc }
  {
    getstored  .code:n            =
      { \tl_set:Nn \l_@@_foreach_cmd_tl { \getstored } },
    getstored  .value_forbidden:n = true,
    typestored .code:n            =
      { \tl_set:Nn \l_@@_foreach_cmd_tl { \typestored } },
    typestored .value_forbidden:n = true,
    meaningsc  .code:n            =
      { \tl_set:Nn \l_@@_foreach_cmd_tl { \meaningsc } },
    meaningsc  .value_forbidden:n = true,
  }
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Internal functions for \cs[no-index]{foreachsc}}
%
% \begin{macro}[int]
%   {
%     \@@_foreachsc:nn,
%     \@@_foreach_add_body:n,
%     \@@_foreach_wrap:n,
%     \@@_foreach_wrap:V,
%   }
%   The function \myhlc|\@@_foreachsc:nn| sets the \mymeta{keys} passed in
%   |#1| and steps from \mykey{start} to \mykey{stop}, the number of
%   \mymeta{stored contents} by default, with \myhlc|\@@_foreach_add_body:n|,
%   which adds the command saved in \myhlc|\l_@@_foreach_cmd_tl|, with the
%   code of the \mykey{before}, \mykey{after} and \mykey{wrapper} keys, to
%   \myhlc|\l_@@_foreach_print_seq|. The result, separated by \mykey{sep},
%   is executed after the group. The function \myhlc|\@@_foreach_wrap:n|
%   expands \myhlc|\@@_foreach_wrapper:n| once inside the group, so the
%   code of the \mykey{wrapper} key is already in place when the result
%   is executed; the function \myhlc|\@@_foreach_wrapper:n| is local and
%   no longer exists after the group.
%    \begin{macrocode}
\cs_new_protected:Npn \@@_foreachsc:nn #1 #2
  {
    \group_begin:
      \tl_if_novalue:nF {#1} { \keys_set:nn { scontents / foreachsc } {#1} }
      \tl_set:Nn \l_@@_foreachsc_arg_tl {#2}
      \seq_clear:N \l_@@_foreach_print_seq
      \bool_if:NF \l_@@_foreach_stop_bool
        {
          \int_set:Nn \l_@@_foreach_stop_int
            { \@@_seq_count:n {#2} }
        }
      \int_step_function:nnnN
        { \l_@@_foreach_start_int }
        { \l_@@_foreach_step_int }
        { \l_@@_foreach_stop_int }
        \@@_foreach_add_body:n
      \tl_gset:Ne \g_@@_foreach_exec_tl
        {
          \exp_args:NNV \seq_use:Nn
            \l_@@_foreach_print_seq \l_@@_foreach_sep_tl
        }
    \group_end:
    \exp_after:w \tl_gclear:N
    \exp_after:w \g_@@_foreach_exec_tl
    \g_@@_foreach_exec_tl
  }
\cs_new_protected:Npn \@@_foreach_add_body:n #1
  {
    \tl_set:Ne \l_@@_foreach_body_tl
      {
        \exp_not:V \l_@@_foreach_cmd_tl [#1]
          { \exp_not:V \l_@@_foreachsc_arg_tl }
      }
    \bool_if:NT \l_@@_foreach_wrapper_bool
      { \@@_foreach_wrap:V \l_@@_foreach_body_tl }
    \seq_put_right:Ne \l_@@_foreach_print_seq
      {
        \bool_if:NT \l_@@_foreach_before_bool
          { \exp_not:V \l_@@_foreach_before_tl }
        \exp_not:V \l_@@_foreach_body_tl
        \bool_if:NT \l_@@_foreach_after_bool
          { \exp_not:V \l_@@_foreach_after_tl }
      }
  }
\cs_new_protected:Npn \@@_foreach_wrap:n #1
  { \tl_set:No \l_@@_foreach_body_tl { \@@_foreach_wrapper:n {#1} } }
\cs_generate_variant:Nn \@@_foreach_wrap:n { V }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\foreachsc}
%   Defines the user command \ics*{foreachsc}.
%    \begin{macrocode}
\NewDocumentCommand \foreachsc { +o m }
  {
    \tl_set:Nn \l_@@_cmd_name_tl { foreachsc }
    \@@_seq_if_exist:nTF {#2}
      { \@@_foreachsc:nn {#1} {#2} }
      { \msg_error:nnn { scontents } { undefined-storage } {#2} }
  }
%    \end{macrocode}
% \end{macro}
%
% \subsection{The optional argument of \cs{typestored}, \cs{meaningsc} and \cs{mergesc}}\label{fun:range-parser}
%
% The commands |\typestored| and |\meaningsc|, and |\mergesc| which uses
% them internally, accept a single \emph{optional argument} with the
% \mymeta{index}, \mymeta{1-end} or the range \mymeta{start-stop} of the
% \mymeta{stored contents} in the \emph{sequence} along with the
% \mymeta{keys}, this avoids the awkward
% |\typestored[...]|\myoarg{keys}|{...}| syntax. The \mymeta{indexes} and
% ranges are processed as unknown \mymeta{keys} of
% \mypkg{l3keys}\cite{inter3,keyval}.
%
% \subsubsection{Definition of variables for the optional argument}
%
% \begin{macro}[int]
%   {
%     \l_@@_current_seq_name_str,
%     \l_@@_index_str,
%     \l_@@_range_start_tl,
%     \l_@@_range_stop_tl,
%   }
%   The string variable \myhlc|\l_@@_current_seq_name_str| stores the name
%   of the \emph{sequence} passed to |\typestored| or |\meaningsc|, it is
%   used by \myhlc|\@@_parse_type_meaning_key:nn|. The string variable
%   \myhlc|\l_@@_index_str| is used to check that an \mymeta{index} only
%   has digits and the token lists \myhlc|\l_@@_range_start_tl| and
%   \myhlc|\l_@@_range_stop_tl| save the limits of a range
%   \mymeta{start-stop}.
%    \begin{macrocode}
\str_new:N \l_@@_current_seq_name_str
\str_new:N \l_@@_index_str
\tl_new:N  \l_@@_range_start_tl
\tl_new:N  \l_@@_range_stop_tl
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Definition of keys for the optional argument}\label{key:typemeaning}
%
% \begin{macro}[int]{width-tab, write-out, overwrite, print-cmd, unknown}
%   We define the common \mymeta{keys} for |\typestored| and |\meaningsc|.
%   The \mykey{write-out}, \mykey{overwrite} and \mykey{print-cmd} keys are
%   necessary for the implementation of |\mergesc| (\S\ref{cmd:mergesc})
%   and the unknown \mymeta{keys} are passed to
%   \myhlc|\@@_parse_type_meaning_key:n|.
%    \begin{macrocode}
\keys_define:nn { scontents / typemeaning }
  {
    width-tab .meta:nn          = { scontents } { width-tab = #1 },
    write-out .code:n           = { \@@_set_write_out:n {#1} },
    write-out .value_required:n = true,
    overwrite .meta:nn          = { scontents } { overwrite = #1 },
    overwrite .default:n        = true,
    print-cmd .bool_set:N       = \l_@@_print_verb_style_bool,
    print-cmd .initial:n        = true,
    print-cmd .default:n        = true,
    unknown   .code:n           = { \@@_parse_type_meaning_key:n {#1} },
  }
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Internal functions for the optional argument}
%
% \begin{macro}[int]
%   {
%     \@@_parse_type_meaning_key:n,
%     \@@_parse_type_meaning_key:nn,
%     \@@_range_parser:nnn,
%     \@@_range_parser:nnnw,
%     \@@_range_limit:nn,
%     \@@_range_step:nn,
%   }
% \begin{macro}[int,TF]{\@@_if_digits:n}
%   The function \myhlc|\@@_parse_type_meaning_key:n| checks that the
%   unknown \mymeta{key} has no value, otherwise something odd as |1=1|
%   was used and the \enquote{error} |cmd-key-value-unknown| is raised.
%   The conditional \myhlc|\@@_if_digits:nTF|
%   tests if |#1| is not blank and only has digits, it removes the digits
%   from \myhlc|\l_@@_index_str|, so a text that is not a number never
%   reaches an \emph{integer expression} and only the \enquote{error} of
%   the package is raised.
%
%   The function \myhlc|\@@_range_parser:nnn| receives the
%   \mymeta{index} or the range in |#1|, the number of
%   \mymeta{stored contents} in |#2| and the code that raises the
%   \enquote{error} in |#3|, and splits |#1| at the hyphens with
%   \myhlc|\@@_range_parser:nnnw|: without hyphen it is an
%   \mymeta{index}, with a hyphen at the beginning it is a negative
%   \mymeta{index} and otherwise it is a range \mymeta{start-stop}, where
%   \myhlc|\@@_range_limit:nn| replaces |end| by the number of
%   \mymeta{stored contents} and \myhlc|\@@_range_step:nn| adds the
%   \mymeta{indexes} of the range, ascending or descending, to
%   \myhlc|\l_@@_seq_item_seq|. Anything else is passed to the code in
%   |#3|.
%    \begin{macrocode}
\cs_new_protected:Npn \@@_parse_type_meaning_key:n #1
  { \exp_args:NV \@@_parse_type_meaning_key:nn \l_keys_key_str {#1} }
\cs_new_protected:Npn \@@_parse_type_meaning_key:nn #1 #2
  {
    \tl_if_blank:nTF {#2}
      {
        \@@_range_parser:nnn {#1}
          { \@@_seq_count:n { \l_@@_current_seq_name_str } }
          { \msg_error:nnn { scontents } { cmd-key-unknown } }
      }
      { \msg_error:nnnn { scontents } { cmd-key-value-unknown } {#1} {#2} }
  }
\prg_new_protected_conditional:Npnn \@@_if_digits:n #1 { TF }
  {
    \str_set:Ne \l_@@_index_str { \tl_trim_spaces:n {#1} }
    \clist_map_inline:nn { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 }
      { \str_remove_all:Nn \l_@@_index_str {##1} }
    \tl_if_blank:nTF {#1}
      { \prg_return_false: }
      {
        \str_if_empty:NTF \l_@@_index_str
          { \prg_return_true: }
          { \prg_return_false: }
      }
  }
\prg_generate_conditional_variant:Nnn \@@_if_digits:n { V } { TF }
\cs_new_protected:Npn \@@_range_parser:nnn #1 #2 #3
  { \@@_range_parser:nnnw {#1} {#2} {#3} #1 - \q_@@_mark - \s_@@_mark }
\cs_new_protected:Npn \@@_range_parser:nnnw #1 #2 #3 #4 - #5 - #6 \s_@@_mark
  {
    \@@_tl_if_head_is_q_mark:nTF {#5}
      {
        \@@_if_digits:nTF {#4}
          { \seq_put_right:Ne \l_@@_seq_item_seq { \int_eval:n {#4} } }
          { #3 {#1} }
      }
      {
        \@@_tl_if_head_is_q_mark:nTF {#6}
          {
            \tl_if_blank:nTF {#4}
              {
                \@@_if_digits:nTF {#5}
                  {
                    \seq_put_right:Ne \l_@@_seq_item_seq
                      { \int_eval:n { - #5 } }
                  }
                  { #3 {#1} }
              }
              {
                \tl_set:Ne \l_@@_range_start_tl
                  { \@@_range_limit:nn {#4} {#2} }
                \tl_set:Ne \l_@@_range_stop_tl
                  { \@@_range_limit:nn {#5} {#2} }
                \@@_if_digits:VTF \l_@@_range_start_tl
                  {
                    \@@_if_digits:VTF \l_@@_range_stop_tl
                      {
                        \exp_args:NVV \@@_range_step:nn
                          \l_@@_range_start_tl \l_@@_range_stop_tl
                      }
                      { #3 {#1} }
                  }
                  { #3 {#1} }
              }
          }
          { #3 {#1} }
      }
  }
\cs_new:Npn \@@_range_limit:nn #1 #2
  {
    \str_if_eq:eeTF { \tl_trim_spaces:n {#1} } { end }
      {#2}
      { \tl_trim_spaces:n {#1} }
  }
\cs_new_protected:Npn \@@_range_step:nn #1 #2
  {
    \int_step_inline:nnnn {#1}
      { \int_compare:nNnTF {#2} < {#1} { -1 } { 1 } }
      {#2}
      { \seq_put_right:Nn \l_@@_seq_item_seq {##1} }
  }
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}[int]{\@@_typemeaning_setup:nn, \l_@@_pending_bool}
%   The function \myhlc|\@@_typemeaning_setup:nn| is the common start of
%   |\typestored| and |\meaningsc|, it saves the name of the
%   \emph{sequence} passed in |#2|, sets the \mymeta{keys} and the
%   \mymeta{indexes} passed in |#1| and uses the first
%   \mymeta{stored content} if no \mymeta{index} was given. The boolean
%   \myhlc|\l_@@_pending_bool| is true if any of them is not available
%   yet in a remembered \emph{sequence} (\S\ref{subsec:remember}).
%    \begin{macrocode}
\bool_new:N \l_@@_pending_bool
\cs_new_protected:Npn \@@_typemeaning_setup:nn #1 #2
  {
    \seq_clear:N \l_@@_seq_item_seq
    \str_set:Ne \l_@@_current_seq_name_str {#2}
    \tl_if_novalue:nF {#1}
      { \keys_set:nn { scontents / typemeaning } {#1} }
    \seq_if_empty:NT \l_@@_seq_item_seq
      { \seq_set_from_clist:Nn \l_@@_seq_item_seq { 1 } }
    \bool_set_false:N \l_@@_pending_bool
    \seq_map_inline:Nn \l_@@_seq_item_seq
      {
        \@@_if_pending:nnT {#2} {##1}
          { \bool_set_true:N \l_@@_pending_bool }
      }
  }
%    \end{macrocode}
% \end{macro}
%
% \subsection{The command \cs{typestored}}\label{cmd:typestored}
%
% The user-level command |\typestored| prints the \mymeta{stored contents}
% of a \emph{sequence} in the |verbatimsc| environment
% (\S\ref{env:verbatimsc}). It takes an optional argument
% (\S\ref{fun:range-parser}) and a mandatory argument with the
% \mymarg{seq name}.
%
% \subsubsection{Definition of variables for \cs[no-index]{typestored}}
%
% \begin{macro}[int]{\l_@@_typestored_arg_tl}
%   The token list \myhlc|\l_@@_typestored_arg_tl| saves the
%   \mymeta{stored contents} to print.
%    \begin{macrocode}
\tl_new:N \l_@@_typestored_arg_tl
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Definition of error messages for \cs[no-index]{typestored}}
%
% \begin{macro}[int]{empty-variable}
%   The \enquote{error} |empty-variable| is raised when the
%   \mymeta{stored contents} to print are blank.
%    \begin{macrocode}
\msg_new:nnnn { scontents } { empty-variable }
  { Blank~stored~content~to~print~\msg_line_context:. }
  {
    The~stored~content~only~has~spaces,~so~there~is~nothing~to~print~
    in~verbatim~style.~Check~the~stored~content~or~the~index.
  }
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Internal functions for \cs[no-index]{typestored}}
%
% \begin{macro}[int]{\@@_typestored:nn}
%   The function \myhlc|\@@_typestored:nn| sets the \mymeta{keys} and the
%   \mymeta{indexes} passed in |#1| with \myhlc|\@@_typemeaning_setup:nn|,
%   gets the \mymeta{stored contents} of the \emph{sequence} named by |#2|,
%   writes them to the \texttt{.log} file if \mykey{debug-var} is true and
%   prints them with \myhlc|\@@_typestored:N| and writes them with
%   \myhlc|\@@_file_write_cmd:VV|.
%    \begin{macrocode}
\cs_new_protected:Npn \@@_typestored:nn #1 #2
  {
    \@@_bsphack:
    \group_begin:
      \@@_typemeaning_setup:nn {#1} {#2}
      \bool_if:NF \l_@@_pending_bool
        {
          \tl_set:Ne \l_@@_typestored_arg_tl
            { \@@_getfrom_seq:Nn \l_@@_seq_item_seq {#2} }
          \@@_remove_trailing_eol:N \l_@@_typestored_arg_tl
          \tl_replace_all:NeV \l_@@_typestored_arg_tl
            { \c_@@_hidden_space_str } \c_@@_newline_tl
          \bool_if:NT \l_@@_debug_var_bool
            {
              \tl_log:N \l_@@_typestored_arg_tl
            }
          \tl_if_empty:NF \l_@@_typestored_arg_tl
            {
              \bool_if:NT \l_@@_print_verb_style_bool
                {
                  \@@_typestored:N \l_@@_typestored_arg_tl
                }
            }
          \@@_file_write_cmd:VV \l_@@_file_name_tl \l_@@_typestored_arg_tl
        }
      \use:e
        {
          \group_end:
          \bool_if:NF \l_@@_print_verb_style_bool { \@@_esphack: }
        }
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{\@@_typestored:N, \@@_verb_print_EOL:}
%   The function \myhlc|\@@_typestored:N| is defined with active carriage
%   return characters to mimic an actual |verbatim| environment
%   \enquote{on the loose}. The content of the token list passed in |#1|
%   is placed in a |verbatimsc| environment and rescanned with
%   \myhlc|\tl_retokenize:e|.
%    \begin{macrocode}
\group_begin:
  \char_set_catcode_active:N \^^M
  \cs_new_protected:Npn \@@_typestored:N #1
    {
      \tl_if_blank:VT #1
        { \msg_error:nn { scontents } { empty-variable } }
      \cs_set_eq:NN \@@_verb_print_EOL: ^^M
      \cs_set_eq:NN ^^M \scan_stop:
      \cs_set_eq:cN { do@noligs } \@@_do_noligs:N
      \int_set:Nn \tex_newlinechar:D { `\^^J }
      \tl_retokenize:e
        {
          \@@_format_case:nnn
            { \exp_not:N \begin{verbatimsc} } % LaTeX
            { \verbatimsc } % Plain/Generic
            { \startverbatimsc } % ConTeXt
            ^^M
          \exp_not:V #1 ^^M
          \g_@@_end_verbatimsc_tl
        }
      \cs_set_eq:NN ^^M \@@_verb_print_EOL:
    }
\group_end:
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\typestored}
%   Defines the user command \ics*{typestored}.
%    \begin{macrocode}
\NewDocumentCommand \typestored { o m }
  {
    \tl_set:Nn \l_@@_cmd_name_tl { typestored }
    \@@_typestored:nn {#1} {#2}
  }
%    \end{macrocode}
% \end{macro}
%
% \subsection{The command \cs{meaningsc}}\label{cmd:meaningsc}
%
% The user-level command |\meaningsc| prints the meaning of the
% \mymeta{stored contents} of a \emph{sequence}. It takes the same
% arguments as |\typestored| (\S\ref{cmd:typestored}).
%
% \subsubsection{Definition of variables for \cs[no-index]{meaningsc}}
%
% \begin{macro}[int]{\l_@@_meaningsc_arg_tl}
%   The token list \myhlc|\l_@@_meaningsc_arg_tl| saves the
%   \mymeta{stored contents} to print.
%    \begin{macrocode}
\tl_new:N \l_@@_meaningsc_arg_tl
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Internal functions for \cs[no-index]{meaningsc}}
%
% \begin{macro}[int]{\@@_meaningsc:nn}
%   The function \myhlc|\@@_meaningsc:nn| sets the \mymeta{keys} and the
%   \mymeta{indexes} passed in |#1| with \myhlc|\@@_typemeaning_setup:nn|
%   and calls \myhlc|\@@_meaningsc:n| with the \emph{sequence} named by
%   |#2|.
%    \begin{macrocode}
\cs_new_protected:Npn \@@_meaningsc:nn #1 #2
  {
    \@@_bsphack:
    \group_begin:
      \@@_typemeaning_setup:nn {#1} {#2}
      \bool_if:NF \l_@@_pending_bool { \@@_meaningsc:n {#2} }
      \use:e
        {
          \group_end:
          \bool_if:NF \l_@@_print_verb_style_bool { \@@_esphack: }
        }
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{\@@_meaningsc:n}
%   The function \myhlc|\@@_meaningsc:n| is defined with the \texttt{TAB}
%   character active. It gets the \mymeta{stored contents}, replaces the
%   ends of line and \myhlc|\c_@@_hidden_space_str| by spaces and each
%   \texttt{TAB} character, active or read from a remembered
%   \emph{sequence} (\S\ref{subsec:remember}), by as many spaces as the
%   \mykey{width-tab} key was set to, prints them with
%   \myhlc|\cs_replacement_spec:N| and writes them with
%   \myhlc|\@@_file_write_cmd:VV|.
%    \begin{macrocode}
\group_begin:
  \char_set_catcode_active:N \^^I
  \cs_new_protected:Npn \@@_meaningsc:n #1
    {
      \tl_set:Ne \l_@@_meaningsc_arg_tl
        { \@@_getfrom_seq:Nn \l_@@_seq_item_seq {#1} }
      \tl_replace_all:Nen \l_@@_meaningsc_arg_tl
        { \iow_char:N \^^J } { ~ }
      \tl_replace_all:Nen \l_@@_meaningsc_arg_tl
        { \c_@@_hidden_space_str } { ~ }
      \bool_if:NT \l_@@_debug_var_bool
        {
          \tl_log:N \l_@@_meaningsc_arg_tl
        }
      \tl_use:N \l_@@_verb_font_tl
      \tl_replace_all:Nne \l_@@_meaningsc_arg_tl
        { ^^I } { \prg_replicate:nn { \l_@@_tab_width_int } { ~ } }
      \tl_replace_all:Nee \l_@@_meaningsc_arg_tl
        { \iow_char:N \^^I }
        { \prg_replicate:nn { \l_@@_tab_width_int } { ~ } }
      \tl_if_empty:NF \l_@@_meaningsc_arg_tl
        {
          \bool_if:NT \l_@@_print_verb_style_bool
            {
              \cs_replacement_spec:N \l_@@_meaningsc_arg_tl
            }
        }
      \@@_file_write_cmd:VV \l_@@_file_name_tl \l_@@_meaningsc_arg_tl
    }
\group_end:
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\meaningsc}
%   Defines the user command \ics*{meaningsc}.
%    \begin{macrocode}
\NewDocumentCommand \meaningsc { o m }
  {
    \tl_set:Nn \l_@@_cmd_name_tl { meaningsc }
    \@@_meaningsc:nn {#1} {#2}
  }
%    \end{macrocode}
% \end{macro}
%
% \subsection{The command \cs{mergesc}}\label{cmd:mergesc}
%
% The user-level command |\mergesc| takes an optional argument with the
% \mymeta{keys} and a mandatory argument with a \emph{comma separated
% list} of \mymarg{seq name} followed by an optional \mymeta{index} or
% range. It assembles the \mymeta{stored contents} in a temporary
% \emph{internal sequence} and passes it to |\typestored| or |\meaningsc|,
% or rescans it as |\getstored| does.
%
% \subsubsection{Definition of variables for \cs[no-index]{mergesc}}
%
% \begin{macro}[int]{\l_@@_mergesc_arg_tl, \l_@@_mergesc_keys_tl}
%   The token list \myhlc|\l_@@_mergesc_arg_tl| saves the last
%   \mymeta{stored content} assembled and the token list
%   \myhlc|\l_@@_mergesc_keys_tl| saves the \mymeta{keys} passed to
%   |\typestored| or |\meaningsc|.
%    \begin{macrocode}
\tl_new:N \l_@@_mergesc_arg_tl
\tl_new:N \l_@@_mergesc_keys_tl
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Definition of error messages for \cs[no-index]{mergesc}}
%
% \begin{macro}[int]{mergesc-missing-key}
%   The \enquote{error} |mergesc-missing-key| is raised when none of the
%   \mykey{typestored}, \mykey{meaningsc} and \mykey{getstored} keys is
%   passed to |\mergesc|.
%    \begin{macrocode}
\msg_new:nnnn { scontents } { mergesc-missing-key }
  {
    Missing~mandatory~key~'typestored',~'meaningsc'~or~'getstored'~
    for~\c_backslash_str mergesc~\msg_line_context:.
  }
  {
    The~command~\c_backslash_str mergesc~needs~one~of~the~keys~
    'typestored',~'meaningsc'~or~'getstored'.\\
    Check~that~you~have~spelled~the~key~name~correctly.
  }
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Definition of keys for \cs[no-index]{mergesc}}
%
% \begin{macro}[int]{typestored, meaningsc, getstored, \@@_mergesc_cmd:nn}
%   The \mymeta{keys} \mykey{typestored}, \mykey{meaningsc} and
%   \mykey{getstored} are \emph{mandatory}, they set the function
%   \myhlc|\@@_mergesc_cmd:nn|, which by default raises the
%   \enquote{error} |mergesc-missing-key|.
%    \begin{macrocode}
\keys_define:nn { scontents / mergesc }
  {
    typestored .code:n            =
      { \cs_set_eq:NN \@@_mergesc_cmd:nn \@@_typestored:nn },
    typestored .value_forbidden:n = true,
    meaningsc  .code:n            =
      { \cs_set_eq:NN \@@_mergesc_cmd:nn \@@_meaningsc:nn },
    meaningsc  .value_forbidden:n = true,
    getstored  .code:n            =
      { \cs_set_eq:NN \@@_mergesc_cmd:nn \@@_mergesc_getstored:nn },
    getstored  .value_forbidden:n = true,
  }
\cs_new_protected:Npn \@@_mergesc_cmd:nn #1 #2
  {
    \msg_error:nn { scontents } { mergesc-missing-key }
  }
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Internal functions for \cs[no-index]{mergesc}}
%
% \begin{macro}[int]{\@@_mergesc_code:nn}
%   The function \myhlc|\@@_mergesc_code:nn| sets the known \mymeta{keys}
%   passed in |#1|, saves the others in \myhlc|\l_@@_mergesc_keys_tl|,
%   assembles the \emph{internal sequence} from the list passed in |#2|
%   and, if it is not empty, passes it to \myhlc|\@@_mergesc_cmd:nn|.
%    \begin{macrocode}
\cs_new_protected:Npn \@@_mergesc_code:nn #1 #2
  {
    \group_begin:
      \tl_clear:N \l_@@_mergesc_keys_tl
      \tl_if_novalue:nF {#1}
        {
          \keys_set_known:nnN { scontents / mergesc } {#1}
            \l_@@_mergesc_keys_tl
        }
      \seq_gclear:c { g_@@_name_sc!internal_seq }
      \@@_mergesc_parse_list:n {#2}
      \seq_if_empty:cF { g_@@_name_sc!internal_seq }
        {
          \exp_args:Ne \@@_mergesc_cmd:nn
            { 1-end, \exp_not:V \l_@@_mergesc_keys_tl } { sc!internal }
        }
    \group_end:
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]
%   {
%     \@@_mergesc_parse_list:n,
%     \@@_mergesc_parse_item:n,
%     \@@_parse_mergesc:nw,
%     \@@_parse_mergesc_aux:nw,
%     \@@_mergesc_put_item:nn,
%   }
%   The function \myhlc|\@@_mergesc_parse_list:n| parses each item of the
%   list with \myhlc|\@@_mergesc_parse_item:n|, which passes the
%   \mymarg{seq name} between braces to \myhlc|\@@_parse_mergesc:nw| when
%   the item has no \mymeta{index}, because the \emph{comma separated
%   list} removes the braces around an item. The function
%   \myhlc|\@@_parse_mergesc:nw| raises the \enquote{error}
%   |undefined-storage| if the \emph{sequence} does not exist and uses all
%   the \mymeta{stored contents} of the \emph{sequence} if there is no
%   \mymeta{index}. The function \myhlc|\@@_parse_mergesc_aux:nw| uses
%   \myhlc|\@@_range_parser:nnn| (\S\ref{fun:range-parser}) and
%   \myhlc|\@@_mergesc_put_item:nn| adds each \mymeta{stored content} to
%   the \emph{internal sequence} or raises the \enquote{error}
%   |index-out-of-range|, except for the \mymeta{stored contents} that
%   are not available yet in a remembered \emph{sequence}
%   (\S\ref{subsec:remember}). Finally the end of line of the last
%   \mymeta{stored content} is removed with
%   \myhlc|\@@_remove_trailing_eol:N|.
%    \begin{macrocode}
\cs_new_protected:Npn \@@_mergesc_parse_list:n #1
  {
    \clist_map_inline:nn {#1} { \@@_mergesc_parse_item:n {##1} }
    \seq_if_empty:cF { g_@@_name_sc!internal_seq }
      {
        \seq_gpop_right:cN { g_@@_name_sc!internal_seq } \l_@@_mergesc_arg_tl
        \@@_remove_trailing_eol:N \l_@@_mergesc_arg_tl
        \seq_gput_right:cV { g_@@_name_sc!internal_seq } \l_@@_mergesc_arg_tl
      }
  }
\cs_new_protected:Npn \@@_mergesc_parse_item:n #1
  {
    \tl_if_in:nnTF {#1} { [ } % ]
      { \@@_parse_mergesc:nw #1 \s_@@_stop }
      { \@@_parse_mergesc:nw {#1} \s_@@_stop }
  }
\cs_new_protected:Npn \@@_parse_mergesc:nw #1
  {
    \@@_seq_if_exist:nTF {#1}
      {
        \peek_remove_spaces:n
          {
            \peek_charcode:NTF [ % ]
              { \@@_parse_mergesc_aux:nw {#1} }
              { \@@_parse_mergesc_aux:nw {#1} [ 1-end ] }
          }
      }
      {
        \msg_error:nnn { scontents } { undefined-storage } {#1}
        \@@_use_none_delimit_by_s_stop:w
      }
  }
\cs_new_protected:Npn \@@_parse_mergesc_aux:nw #1 [#2]
  {
    \seq_clear:N \l_@@_seq_item_seq
    \clist_map_inline:nn {#2}
      {
        \@@_range_parser:nnn {##1} { \@@_seq_count:n {#1} }
          { \msg_error:nnn { scontents } { cmd-key-unknown } }
      }
    \seq_map_inline:Nn \l_@@_seq_item_seq
      { \@@_mergesc_put_item:nn {#1} {##1} }
    \@@_use_none_delimit_by_s_stop:w
  }
\cs_new_protected:Npn \@@_mergesc_put_item:nn #1 #2
  {
    \@@_if_pending:nnF {#1} {#2}
      {
        \bool_lazy_or:nnTF
          { \int_compare_p:nNn {#2} = { 0 } }
          {
            \int_compare_p:nNn { \int_abs:n {#2} }
              > { \@@_seq_count:n {#1} }
          }
          {
            \msg_error:nneee { scontents } { index-out-of-range }
              {#2} {#1} { \@@_seq_count:n {#1} }
          }
          {
            \seq_gput_right:ce { g_@@_name_sc!internal_seq }
              { \@@_seq_item:nn {#1} {#2} }
          }
      }
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{\@@_mergesc_getstored:nn}
%   The function \myhlc|\@@_mergesc_getstored:nn|, set by the
%   \mykey{getstored} key, joins the \mymeta{stored contents} of the
%   \emph{internal sequence} passed in |#2| in
%   \myhlc|\g_@@_last_stored_tl| separated by an end of line, adds
%   \myhlc|\c_@@_hidden_space_str| at the end, because the last one has
%   no end of line, and rescans them with \myhlc|\tl_retokenize:V| after
%   the group of |\mergesc|, as \myhlc|\@@_lastfrom_seq:n| does
%   (\S\ref{fun:sequences}). The result is the same as using |\getstored|
%   on each \mymeta{stored content}. The
%   \mymeta{indexes} passed in |#1| are always |1-end| and the other
%   \mymeta{keys}, saved in \myhlc|\l_@@_mergesc_keys_tl|, are unknown for
%   it and raise the \enquote{errors} of the unknown \mymeta{keys}
%   (\S\ref{key:unknown-keys}).
%    \begin{macrocode}
\keys_define:nn { scontents / getstored }
  {
    unknown .code:n = { \@@_unknown_keys_cmd:n {#1} },
  }
\cs_new_protected:Npn \@@_mergesc_getstored:nn #1 #2
  {
    \keys_set:nV { scontents / getstored } \l_@@_mergesc_keys_tl
    \tl_gset:Ne \g_@@_last_stored_tl
      {
        \exp_args:NnV \seq_use:cn { g_@@_name_#2_seq } \c_@@_newline_tl
        \c_@@_hidden_space_str
      }
    \group_insert_after:N \tl_retokenize:V
    \group_insert_after:N \g_@@_last_stored_tl
    \group_insert_after:N \tl_gclear:N
    \group_insert_after:N \g_@@_last_stored_tl
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\mergesc}
%   Defines the user command \ics*{mergesc}.
%    \begin{macrocode}
\NewDocumentCommand \mergesc { o m }
  {
    \tl_set:Nn \l_@@_cmd_name_tl { mergesc }
    \@@_mergesc_code:nn {#1} {#2}
  }
%    \end{macrocode}
% \end{macro}
%
% \subsection{The command \cs{setupsc}}\label{cmd:setupsc}
%
% \begin{macro}{\setupsc}
%   Defines the user command \ics*{setupsc}, which sets the \mymeta{keys}
%   of the package (\S\ref{key:package}).
%    \begin{macrocode}
\NewDocumentCommand \setupsc { +m }
  {
    \tl_set:Nn \l_@@_cmd_name_tl { setupsc }
    \keys_set:nn { scontents } {#1}
  }
%    \end{macrocode}
% \end{macro}
%
% \subsection{The command \cs{countsc}}\label{cmd:countsc}
%
% \begin{macro}{\countsc}
%   Defines the user command \ics*{countsc}, which counts the
%   \mymeta{stored contents} in the \emph{sequence}. If the
%   \emph{sequence} does not exist, the \enquote{error}
%   |undefined-storage| is raised and |0| is returned.
%    \begin{macrocode}
\NewExpandableDocumentCommand \countsc { m }
  {
    \@@_seq_if_exist:nTF {#1}
      { \@@_seq_count:n {#1} }
      {
        \msg_expandable_error:nnn { scontents } { undefined-storage } {#1}
        0
      }
  }
%    \end{macrocode}
% \end{macro}
%
% \subsection{The command \cs{cleanseqsc}}\label{cmd:cleanseqsc}
%
% \begin{macro}{\cleanseqsc}
%   Defines the user command \ics*{cleanseqsc}, which removes all the
%   \mymeta{stored contents} in the \emph{sequence}.
%    \begin{macrocode}
\NewDocumentCommand \cleanseqsc { m }
  {
    \seq_gclear_new:c { g_@@_name_#1_seq }
  }
%</core>
%    \end{macrocode}
% \end{macro}
%
% \subsection{Programming interface}\label{fun:api}
%
% The public functions of \mypkg*[no-index]{scontents} for \mypkg{expl3}
% (\S\ref{sec:api}), they use the functions for sequences
% (\S\ref{fun:sequences}).
%
% \subsubsection{Definition of variables for the programming interface}
%
% \begin{macro}[int]{\g_@@_map_int, \l_@@_map_item_tl}
%   The integer variable \myhlc|\g_@@_map_int| is the nesting level of
%   \myhlc|\scontents_map_inline:nn|, used in the name of the function that
%   saves each \mymarg{inline function}, and the token list
%   \myhlc|\l_@@_map_item_tl| saves each \mymeta{stored content}.
%    \begin{macrocode}
%<*core>
\int_new:N \g_@@_map_int
\tl_new:N  \l_@@_map_item_tl
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Public functions of the programming interface}
%
% \begin{macro}[EXP,pTF]{\scontents_if_exist:n}
% \begin{macro}[EXP]{\scontents_count:n}
%   The conditional \myhlc|\scontents_if_exist:nTF| and the function
%   \myhlc|\scontents_count:n| use \myhlc|\@@_seq_if_exist:nTF| and
%   \myhlc|\@@_seq_count:n|.
%    \begin{macrocode}
\prg_new_conditional:Npnn \scontents_if_exist:n #1 { p, T, F, TF }
  {
    \@@_seq_if_exist:nTF {#1}
      { \prg_return_true: }
      { \prg_return_false: }
  }
\cs_new:Npn \scontents_count:n #1 { \@@_seq_count:n {#1} }
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\scontents_get:nnN}
% \begin{macro}[int]{\@@_get:nnN}
%   The function \myhlc|\scontents_get:nnN| evaluates the \mymeta{index} and
%   passes it to \myhlc|\@@_get:nnN|, which sets the token list passed in
%   |#3| to the \mymeta{stored content} given by \myhlc|\@@_seq_item:nn|
%   and removes \myhlc|\c_@@_hidden_space_str| from its end with
%   \myhlc|\@@_remove_trailing_eol:N|. Otherwise the token list is empty
%   and the \enquote{errors} |undefined-storage| or |index-out-of-range|
%   are raised, except for a \mymeta{stored content} that is not available
%   yet in a remembered \emph{sequence} (\S\ref{subsec:remember}).
%    \begin{macrocode}
\cs_new_protected:Npn \scontents_get:nnN #1 #2 #3
  { \exp_args:Nne \@@_get:nnN {#1} { \int_eval:n {#2} } #3 }
\cs_new_protected:Npn \@@_get:nnN #1 #2 #3
  {
    \tl_clear:N #3
    \@@_seq_if_exist:nTF {#1}
      {
        \@@_if_pending:nnF {#1} {#2}
          {
            \bool_lazy_or:nnTF
              { \int_compare_p:nNn {#2} = { 0 } }
              {
                \int_compare_p:nNn { \int_abs:n {#2} }
                  > { \@@_seq_count:n {#1} }
              }
              {
                \msg_error:nneee { scontents } { index-out-of-range }
                  {#2} {#1} { \@@_seq_count:n {#1} }
              }
              {
                \tl_set:Ne #3 { \@@_seq_item:nn {#1} {#2} }
                \@@_remove_trailing_eol:N #3
              }
          }
      }
      { \msg_error:nnn { scontents } { undefined-storage } {#1} }
  }
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\scontents_map_inline:nn}
% \begin{macro}[int]{\@@_map_inline:nn}
%   The function \myhlc|\scontents_map_inline:nn| increases
%   \myhlc|\g_@@_map_int|, defines with the \mymarg{inline function}
%   passed in |#2| a function whose name has the nesting level and calls
%   \myhlc|\@@_map_inline:nn|, which gets each \mymeta{stored content}
%   with \myhlc|\@@_get:nnN| and passes it to that function. Each nesting
%   level has its own function, so the \mymarg{inline function} can use
%   \myhlc|\scontents_map_inline:nn| again.
%    \begin{macrocode}
\cs_new_protected:Npn \scontents_map_inline:nn #1 #2
  {
    \@@_seq_if_exist:nTF {#1}
      {
        \int_gincr:N \g_@@_map_int
        \cs_gset_protected:cpn { @@_map_ \int_use:N \g_@@_map_int :n }
          ##1 {#2}
        \exp_args:Nne \@@_map_inline:nn {#1} { \int_use:N \g_@@_map_int }
        \int_gdecr:N \g_@@_map_int
      }
      { \msg_error:nnn { scontents } { undefined-storage } {#1} }
  }
\cs_new_protected:Npn \@@_map_inline:nn #1 #2
  {
    \int_step_inline:nn { \@@_seq_count:n {#1} }
      {
        \@@_get:nnN {#1} {##1} \l_@@_map_item_tl
        \exp_args:Nc \exp_args:NV { @@_map_ #2 :n } \l_@@_map_item_tl
      }
  }
%</core>
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
% \subsection{Finish package}\label{subsec:finish}
%
% Finish package implementation, in \hologo{ConTeXt} `|!|' is a letter
% again (\S\ref{subsubsec:generic-layer}).
%
%    \begin{macrocode}
%<context>\char_set_catcode_letter:N \!
%<plain|context>\ExplSyntaxOff
%<plain|context>\endinput
%<latex|core>\file_input_stop:
%    \end{macrocode}
%
% \Finale