%%
%% algorithmlite.sty
%% =================
%% A lightweight algorithm float without the float package.
%%
%% Copyright (c) 2026 Munehiro Yamamoto <munepixyz@gmail.com>
%%
%% This package is licensed 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
%%
%% This work has the LPPL maintenance status `maintained'.
%% The Current Maintainer of this work is Munehiro Yamamoto.
%%
%% Background
%%   The algorithm package defines the algorithm float with \newfloat of
%%   the float package, and the float package redefines \caption as a
%%   whole for every document.
%%
%% What this package does
%%   It defines the environments algorithm and algorithm* in the same
%%   way as the standard classes define figure and table, with the
%%   \@float and \@dblfloat of the LaTeX kernel:
%%     (1) the counter algorithm is reset at every chapter, and
%%         \thealgorithm is "<chapter>.<n>" (or "<n>" before the first
%%         chapter), if \chapter is defined; otherwise "<n>";
%%     (2) the default placement is tbp, the float type is the next free
%%         one (4 in most documents; shared with the float, floatrow,
%%         newfloat packages and memoir), and the list file is .loa;
%%     (3) \algorithmname, \listalgorithmname and \listofalgorithms;
%%         Japanese names with pTeX/upTeX and LuaTeX-ja;
%%     (4) the placement [H] (here, no float) for every float type if
%%         the float package or the floatrow package does not give one;
%%     (5) Tagged PDF (\DocumentMetadata{tagging=on}): the structure
%%         names of the float type algorithm, and the tagging of [H].
%%   The content of an algorithm (algorithmic, algpseudocode, ...) is
%%   loaded by the user.
%%
%% Limitations
%%   * The algorithm and algorithm2e packages cannot be used with this
%%     package (error).
%%   * algorithm*[H] in two-column mode is not supported (as with the
%%     float package).
%%   * Vertical writing (tate) is out of the scope of this version.
%%
%% Supported formats/engines: pdfLaTeX, XeLaTeX, LuaLaTeX, pLaTeX and
%% upLaTeX (+ dvipdfmx).
%%
\NeedsTeXFormat{LaTeX2e}[2020/10/01]
\ProvidesPackage{algorithmlite}
  [2026/10/28 v1.1 A lightweight algorithm float without the float package]

%% -----------------------------------------------------------------
%% 0. Conflicts with the algorithm and algorithm2e packages
%% -----------------------------------------------------------------
\def\algorithmlite@conflict#1{%
  \PackageError{algorithmlite}
    {Package `#1' cannot be used with algorithmlite}
    {Both define the algorithm environment; load only one of them.}}
\newif\ifalgorithmlite@stop
\@for\algorithmlite@tempa:={algorithm,algorithm2e}\do{%
  \@ifpackageloaded\algorithmlite@tempa
    {\algorithmlite@conflict\algorithmlite@tempa
     \global\algorithmlite@stoptrue}{}}
\ifalgorithmlite@stop\else
  \@tempswafalse
  \@ifundefined{c@algorithm}{\@ifundefined{algorithm}{}{\@tempswatrue}}
    {\@tempswatrue}
  \if@tempswa
    \PackageError{algorithmlite}
      {The algorithm environment or counter is already defined}
      {algorithmlite will not redefine it.}%
    \algorithmlite@stoptrue
  \fi
\fi
\ifalgorithmlite@stop\expandafter\endinput\fi
\AddToHook{package/algorithm/before}{\algorithmlite@conflict{algorithm}}
\AddToHook{package/algorithm2e/before}{\algorithmlite@conflict{algorithm2e}}

%% -----------------------------------------------------------------
%% 1. Names
%% -----------------------------------------------------------------
\newcommand\algorithmname{Algorithm}
\newcommand\listalgorithmname{List of Algorithms}
\let\algorithmlite@en@name\algorithmname
\def\algorithmlite@japanese{%
  \renewcommand\algorithmname{アルゴリズム}%
  \renewcommand\listalgorithmname{アルゴリズム目次}}
%% \algorithmlite@ifenglish{<true>}{<false>}: the option english of
%% jsclasses and the LuaTeX-ja classes
\def\algorithmlite@ifenglish{%
  \@ifundefined{if@english}\@secondoftwo
    {\csname if@english\endcsname
       \expandafter\@firstoftwo\else\expandafter\@secondoftwo\fi}}
\def\algorithmlite@setjapanese{%
  \algorithmlite@ifenglish{}{\algorithmlite@japanese}}
\ifdefined\kanjiskip
  \algorithmlite@setjapanese
\else
  \@ifpackageloaded{luatexja}
    {\algorithmlite@setjapanese}
    {\AddToHook{package/luatexja/after}{%
       \ifx\algorithmname\algorithmlite@en@name
         \algorithmlite@setjapanese
       \fi}}
\fi

%% -----------------------------------------------------------------
%% 2. Counter
%% -----------------------------------------------------------------
\@ifundefined{c@chapter}
  {\newcounter{algorithm}%
   \renewcommand\thealgorithm{\@arabic\c@algorithm}}
  {\newcounter{algorithm}[chapter]%
   \renewcommand\thealgorithm{%
     \ifnum\c@chapter>\z@\thechapter.\fi\@arabic\c@algorithm}}

%% \fnum@algorithm: "\algorithmname<sep>\thealgorithm", where <sep> is
%% taken from \fnum@figure of the class if it is
%% "\figurename<sep>\thefigure" (\nobreakspace in article, \nobreak in
%% jsclasses, ~ in jarticle, nothing in jlreq).  Otherwise, and with
%% the option english of jsclasses (whose \figurename ends with a
%% space), <sep> is \nobreak for Japanese names and \nobreakspace for
%% the others.
\def\algorithmlite@sep{%
  \ifx\algorithmname\algorithmlite@en@name\nobreakspace\else\nobreak\fi}
\def\algorithmlite@parse#1\figurename#2\thefigure#3\algorithmlite@nil{%
  \def\@tempa{#1#3}%
  \ifx\@tempa\@empty\def\algorithmlite@sep{#2}\fi}
\algorithmlite@ifenglish{}{%
  \ifdefined\fnum@figure
    \def\@tempa{\in@\figurename}%
    \expandafter\@tempa\expandafter{\fnum@figure}%
    \ifin@
      \def\@tempa{\in@\thefigure}%
      \expandafter\@tempa\expandafter{\fnum@figure}%
      \ifin@
        \expandafter\algorithmlite@parse\fnum@figure\algorithmlite@nil
      \fi
    \fi
  \fi}
\def\fnum@algorithm{\algorithmname\algorithmlite@sep\thealgorithm}

%% -----------------------------------------------------------------
%% 3. Float type
%%    \ftype@<type> is a bit: figure = 1, table = 2.  The next free bit
%%    is taken from the counter of the float package (also used by
%%    floatrow and newfloat) or of memoir.  If neither is there yet, 4
%%    is taken, and the counter of the float package is moved to 8 when
%%    the package is loaded later (newfloat alone starts at 8).
%% -----------------------------------------------------------------
\@ifundefined{c@float@type}
  {\@ifundefined{c@newflo@tctr}
     {\def\ftype@algorithm{4}%
      \def\algorithmlite@movefloattype{%
        \ifnum\value{float@type}=4 \setcounter{float@type}{8}\fi}%
      \AddToHook{package/float/after}{\algorithmlite@movefloattype}%
      \AddToHook{package/floatrow/after}{\algorithmlite@movefloattype}}
     {\edef\ftype@algorithm{\the\c@newflo@tctr}%
      \global\advance\c@newflo@tctr\c@newflo@tctr}}
  {\edef\ftype@algorithm{\the\value{float@type}}%
   \addtocounter{float@type}{\value{float@type}}}

%% -----------------------------------------------------------------
%% 4. The environments algorithm and algorithm*
%% -----------------------------------------------------------------
\def\fps@algorithm{tbp}
\def\ext@algorithm{loa}
\newenvironment{algorithm}
  {\@float{algorithm}}
  {\end@float}
\newenvironment{algorithm*}
  {\@dblfloat{algorithm}}
  {\end@dblfloat}
%% Tagged PDF: the structure names float/algorithm, ... are set up with
%% \tagpdfsetup{float/new=algorithm}, unless the document has done it
%% in the preamble (doing it twice is an error).
\ExplSyntaxOn
\keys_if_exist:nnT { __tag / setup } { float/new }
  {
    \AddToHook { begindocument }
      {
        \cs_if_exist:cF { l__tag_name_float/algorithm_tl }
          { \tagpdfsetup { float/new = algorithm } }
      }
  }
\ExplSyntaxOff

%% -----------------------------------------------------------------
%% 5. List of algorithms
%%    \listoffigures of the class is used, with \listalgorithmname and
%%    the .loa file.
%% -----------------------------------------------------------------
\@ifundefined{l@figure}
  {\newcommand*\l@algorithm{\@dottedtocline{1}{1.5em}{2.3em}}}
  {\let\l@algorithm\l@figure}
\newcommand\listofalgorithms{%
  \begingroup
    \let\listfigurename\listalgorithmname
    \let\algorithmlite@starttoc\@starttoc
    \def\@starttoc##1{\algorithmlite@starttoc{loa}}%
    \@ifundefined{listoffigures}
      {\section*{\listalgorithmname}%
       \@mkboth{\listalgorithmname}{\listalgorithmname}%
       \@starttoc{loa}}
      {\listoffigures}%
  \endgroup}

%% -----------------------------------------------------------------
%% 6. The placement [H]
%%    Defined at \begin{document} unless the float package or the
%%    floatrow package gives one.  As with the float package, [H] is
%%    then available for every float type.  The end of the current
%%    environment (\@currenvir) is replaced, so that [H] works also for
%%    algorithm* in one-column mode and for an environment that calls
%%    \@float directly.  In the box, \@captype is the float type and
%%    \@fps is H, as \@xfloat sets them for the other placements (the
%%    [H] of the float package does not set \@fps).
%%    Tagged PDF: the float is a structure in the text flow, as the [H]
%%    of the float package is tagged by latex-lab (firstaid).
%% -----------------------------------------------------------------
\newsavebox\algorithmlite@box
\let\algorithmlite@tagHbegin\@gobble
\let\algorithmlite@tagHend\relax
\ifdefined\NewTaggingSocket
  \ExplSyntaxOn
  \NewTaggingSocket { algorithmlite/H/begin } { 1 }
  \NewTaggingSocketPlug { algorithmlite/H/begin } { default }
    {
      \mode_if_horizontal:T { \tag_mc_end_push: \tag_struct_end: }
      \tag_struct_begin:n { tag = \UseStructureName { float/#1 } }
    }
  \AssignTaggingSocketPlug { algorithmlite/H/begin } { default }
  \NewTaggingSocket { algorithmlite/H/end } { 0 }
  \NewTaggingSocketPlug { algorithmlite/H/end } { default }
    {
      \tag_struct_end:
      \mode_if_horizontal:T
        {
          \tag_struct_begin:n { tag = \UseStructureName { para/textblock } }
          \tag_mc_begin_pop:n { }
        }
    }
  \AssignTaggingSocketPlug { algorithmlite/H/end } { default }
  \ExplSyntaxOff
  \def\algorithmlite@tagHbegin{\UseTaggingSocket{algorithmlite/H/begin}}
  \def\algorithmlite@tagHend{\UseTaggingSocket{algorithmlite/H/end}}
\fi
\def\algorithmlite@HH#1[H]{\algorithmlite@tagHbegin{#1}%
  \expandafter\let\csname end\@currenvir\endcsname\algorithmlite@endH
  \let\@currbox\algorithmlite@box
  \def\@captype{#1}%
  \def\@fps{H}%
  \setbox\@currbox\color@vbox\normalcolor
    \vbox\bgroup \hsize\columnwidth \@parboxrestore
      \@floatboxreset \@setnobreak
  \ignorespaces}
\def\algorithmlite@endH{\@endfloatbox\algorithmlite@tagHend
  \vskip\intextsep
  \box\@currbox
  \vskip\intextsep\relax}
\def\algorithmlite@defineH{%
  \let\algorithmlite@Hx\@xfloat
  \def\@xfloat##1[{%
    \@ifnextchar{H}
      {\algorithmlite@HH{##1}[}
      {\algorithmlite@Hx{##1}[}}}
\AtBeginDocument{%
  \@ifpackageloaded{float}{}{%
    \@ifpackageloaded{floatrow}{}{%
      \@ifundefined{@float@HH}{\algorithmlite@defineH}{}}}}

\endinput