Add \g_@@_{latex_option{s_seq,_types_prop},default_latex_options_prop}

Progresses #124.

markdown.dtx

@@ -14409,6 +14409,19 @@ pdflatex --shell-escape document.tex
 % are rendered. The rest of the interface is inherited from the plain \TeX{}
 % interface (see Section <#sec:texinterface>).
 %
+% The \LaTeX{} implementation redefines the plain \TeX{} logging macros (see
+% Section <#sec:texinterfacelogging>) to use the \LaTeX{} \mref{PackageInfo},
+% \mref{PackageWarning}, and \mref{PackageError} macros.
+%
+% \end{markdown}
+%  \begin{macrocode}
+\newcommand\markdownInfo[1]{\PackageInfo{markdown}{#1}}%
+\newcommand\markdownWarning[1]{\PackageWarning{markdown}{#1}}%
+\newcommand\markdownError[2]{\PackageError{markdown}{#1}{#2.}}%
+\input markdown/markdown
+%    \end{macrocode}
+% \begin{markdown}
+%
 % The \LaTeX{} interface is implemented by the `markdown.sty` file, which
 % can be loaded from the \LaTeX{} document preamble as follows:
 % \end{markdown}
@@ -14588,9 +14601,45 @@ document:
 }
 ```
 
+%</manual-options>
+%<*latex>
 % \fi
 % \par
 % \begin{markdown}
+%
+% To enable the enumeration of \LaTeX{} options, we will maintain the
+% \mdef{g_\@\@_latex_options_seq} sequence.
+%
+% \end{markdown}
+%  \begin{macrocode}
+\ExplSyntaxOn
+\seq_new:N \g_@@_latex_options_seq
+%    \end{macrocode}
+% \begin{markdown}
+%
+% To enable the reflection of default \LaTeX{} options and their types, we
+% will maintain the \mdef{g_\@\@_default_latex_options_prop} and
+% \mdef{g_\@\@_latex_option_types_prop} property lists, respectively.
+%
+% \end{markdown}
+%  \begin{macrocode}
+\prop_new:N \g_@@_latex_option_types_prop
+\prop_new:N \g_@@_default_latex_options_prop
+\tl_const:Nn \c_@@_option_category_latex_tl { latex }
+\seq_put_right:NV \g_@@_option_categories_seq \c_@@_option_category_latex_tl
+\cs_new:Nn
+  \@@_add_latex_option:nnn
+  {
+    \@@_add_option:Vnnn
+      \c_@@_option_category_latex_tl
+      { #1 }
+      { #2 }
+      { #3 }
+  }
+%    \end{macrocode}
+% \iffalse
+%</latex>
+%<*manual-options>
 
 #### No default token renderer prototypes {#latexplain}
 
@@ -14614,6 +14663,11 @@ from being loaded:
 %<*latex>
 % \fi
 %  \begin{macrocode}
+\@@_add_latex_option:nnn
+  { plain }
+  { boolean }
+  { false }
+\ExplSyntaxOff
 \newif\ifmarkdownLaTeXPlain
   \markdownLaTeXPlainfalse
 \define@key{markdownOptions}{plain}[true]{%
@@ -22063,16 +22117,8 @@ end
 % format~[@latex17, Section 9]. As a consequence, we can directly reuse the
 % existing plain \TeX{} implementation.
 %
-% The \LaTeX{} implementation redefines the plain \TeX{} logging macros (see
-% Section <#sec:texinterfacelogging>) to use the \LaTeX{} \mref{PackageInfo},
-% \mref{PackageWarning}, and \mref{PackageError} macros.
-%
 % \end{markdown}
 %  \begin{macrocode}
-\newcommand\markdownInfo[1]{\PackageInfo{markdown}{#1}}%
-\newcommand\markdownWarning[1]{\PackageWarning{markdown}{#1}}%
-\newcommand\markdownError[2]{\PackageError{markdown}{#1}{#2.}}%
-\input markdown/markdown
 \def\markdownVersionSpace{ }%
 \ProvidesPackage{markdown}[\markdownLastModified\markdownVersionSpace v%
   \markdownVersion\markdownVersionSpace markdown renderer]%