% \iffalse meta-comment
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% forest-ext-ling.dtx
% Additions and changes Copyright (C) 2025-2026 Clea F. Rees.
% Code from skeleton.dtx Copyright (C) 2015-2024 Scott Pakin (see below).
%
% 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 2008-05-04 or later.
%
% This work has the LPPL maintenance status 'muaintained'.
%
% The Current Maintainer of this work is Clea F. Rees.
%
% This work consists of all files listed in manifest.txt.
%
% The file forest-ext-ling.dtx is a derived work under the terms of the
% LPPL. It is based on version 2.4 of skeleton.dtx which is part of
% dtxtut by Scott Pakin. A copy of dtxtut, including the
% unmodified version of skeleton.dtx is available from
% https://www.ctan.org/pkg/dtxtut and released under the LPPL.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% \fi
%
% \iffalse
%<*driver>
\RequirePackage{svn-prov}
% ref. ateb Max Chernoff: https://tex.stackexchange.com/a/723294/
\def\MakePrivateLetters{\makeatletter\ExplSyntaxOn\endlinechar13}
\ExplSyntaxOff
\ProvidesFileSVN{$Id: forest-ext-ling.dtx 11668 2026-02-21 02:34:38Z cfrees $}[v0.3 \revinfo][\filebase DTX: ]
\DefineFileInfoSVN[forest-ext-ling]
\documentclass[11pt,british]{ltxdoc}
% ^^A l3doc, minted both load fancyvrb
% ^^A fancyvrb overwrites svn-prov's macros without warning
% ^^A restore \fileversion \filerev in case we're using something troublesome
\GetFileInfoSVN{forest-ext-ling}
\begin{document}
\DocInput{\filename}
\end{document}
%</driver>
% \fi
%
% \title{ext.ling}
% \author{Clea F. Rees\thanks{%
%     Bug tracker:
%     \href{https://codeberg.org/cfr/prooftrees/issues}{\url{codeberg.org/cfr/prooftrees/issues}}
%     \textbar{} Code:
%     \href{https://codeberg.org/cfr/prooftrees}{\url{codeberg.org/cfr/prooftrees}}
%     % \textbar{} Mirror:
%     % \href{https://github.com/cfr42/prooftrees}{\url{github.com/cfr42/prooftrees}}% 
% }}
% \date{\forestextdocdate}
% \maketitle
%
% ^^A forest-lib-ext.ling{-debug} 
% ^^A <<< 
%<*sty>
% \permissivelines
%    \begin{macrocode}
\NeedsTeXFormat{LaTeX2e}
%% $Id: forest-ext-ling.dtx 11668 2026-02-21 02:34:38Z cfrees $}
%<!debug>    \ProvidesForestLibrary{ext.ling}[2025-12-05 v0.1]
%<debug>    \ProvidesForestLibrary{ext.ling-debug}[2025-12-05 v0.1]
%
%<!debug>    \disable@package@load {forest-lib-ext.ling-debug}
%<debug>    \disable@package@load {forest-lib-ext.ling}
{%
%<!debug>      \PackageWarning {ext.ling (forest library)}
%<debug>      \PackageWarning {ext.ling-debug (forest library)}
  {Only one of ext.ling and ext.ling-debug should be loaded.
    Since the
%<!debug>        ext.ling
%<debug>        ext.ling-debug
    library has already been loaded, I will ignore your request for
%<!debug>        ext.ling-debug.%
%<debug>        ext.ling.%
  }%
}
%    \end{macrocode}
%<*debug>
% ^^A Paid â defnyddio \GetFileInfoSVN*/\GetFileInfoSVN{} yn y fan hon!!
% ^^A multidom <<<
% \begin{drop}
%    \begin{macrocode}
%<!debug>    \useforestlibrary{ext.multi}
%<debug>    \useforestlibrary{ext.multi-debug}
\forestset{
%    \end{macrocode}
% \texseans[My answer:]{695602}.
% \texseans{695600}[Alan Munn], which was based on my original answer.
%
% Internal registers.
%    \begin{macrocode}
  declare dimen register={multidom@dimx},
  multidom@dimx'=0pt,
  declare dimen register={multidom@dimy},
  multidom@dimy'=0pt,
  declare toks register={multidom@toksa},
  multidom@toksa={},
  declare toks register={multidom@toksb},
  multidom@toksb={},
  declare toks register={multidom@toksc},
  multidom@toksc={},
  declare toks register={multidom@toksd},
  multidom@toksd={},
%    \end{macrocode}
% \begin{fstyle}{multidom@aux}
% First split the argument on colons.
% If there's no sixth argument, re-split to \texttt{curve to also parent}; o/w split out the first argument to (send back to) \texttt{multidom}, storing remaining arguments.
%    \begin{macrocode}
  multidom@aux/.style={%
%<debug>    debug@multidom=Executing style multidom@aux at,
%<debug>    debug@multidom@option=id,
    if={>__={#1}{}}{}{
      multidom@toksa={},
      multidom@toksb={},
      multidom@toksc={},
      multidom@toksd={},
      multidom@dimx'=0pt,
      multidom@dimy'=0pt,
      split={#1}{:}{%
        multidom@toksa,multidom@toksa,%
        multidom@toksa,multidom@toksb,%
        multidom@toksc,multidom@toksd%
      },
      if={>{R_=}{multidom@toksd}{}}{% no sixth arg -> resplit -> curve to also parent
        split={#1}{:}{%
          multidom@toksa,multidom@toksb,multidom@toksc%
        },
        curve to also parent/.process={%
          RRR
          {multidom@toksa}
          {multidom@toksb}
          {multidom@toksc}%
        },      
      }{% sixth arg -> (first) multidom
        split={#1}{:}{%
          multidom@toksa,multidom@dimx,%
          multidom@dimy,multidom@toksb,%
          multidom@toksc,multidom@toksd%
        },
%<debug>    debug@multidom@register=multidom@dimx,
%<debug>    debug@multidom@register=multidom@dimy,
        multidom/.process={%
          RRRRRR
          {multidom@toksa}{multidom@dimx}
          {multidom@dimy}{multidom@toksb}
          {multidom@toksc}{multidom@toksd}%
        },
      },
    },
  },
%    \end{macrocode}
% \end{fstyle}
% \begin{fstyle}{curve to also parent,curve to also parent+,+curve to also parent}
%   Draws a curved edge from the current node to an additional extant parent\texseans[Parameterised from \texse{}:]{249615}.
%
%   Why do I need to double hashes twice here?
%    \begin{macrocode}
  curve to also parent/.style n args=3{%
%<debug>    debug@multidom=Executing style curve to also parent at,
%<debug>    debug@multidom@option=id,
    also parent={#1}{%
      #3:{%
        multidom@curved@edge=from (!c fosterling.#2) 
          to (!c foster parent.parent anchor)%
      }%
    },
  },
  +curve to also parent/.style 2 args={%
%<debug>    debug@multidom=Executing style +curve to also parent at,
%<debug>    debug@multidom@option=id,
    +also parent={%
      #2:{%
        multidom@curved@edge=from (!c fosterling.#1) 
          to (!c foster parent.parent anchor)%
      }%
    },
  },
  curve to also parent+/.style 2 args={%
%<debug>    debug@multidom=Executing style curve to also parent+ at,
%<debug>    debug@multidom@option=id,
    also parent+={%
      #2:{%
        multidom@curved@edge=from (!c fosterling.#1) 
          to (!c foster parent.parent anchor)%
      }%
    },
  },
%    \end{macrocode}
% \end{fstyle}
% \begin{fstyle}{multidom}
%   \texseans{695600}[Alan Munn], which was based on my original answer.
%   Draws a curved edge from the current node to its parent and from the current node to an additional extant parent.
%
% Arguments: 
% \begin{itemize}[label={}]
%   \item prepend\textbar append (\textbar other??)
%   \item xshift for tree rooted at current node
%   \item yshift for tree rooted at current node
%   \item out to structural parent
%   \item out to node
%   \item node
% \end{itemize}
% \texseans[Parameterised from]{249615}.
%    \begin{macrocode}
  multidom/.style n args=6{%
%<debug>    debug@multidom=Executing style multidom at,
%<debug>    debug@multidom@option=id,
%<debug>    debug@multidom=Executing style also parent with #1 #5 and #6,
    also parent={#1}{%
      #6:{%
        multidom@curved@edge=from (!c fosterling.#5) 
          to (#6.parent anchor)%
      }%
    },
%<debug>    debug@multidom=Executing style multidom@curved@edge from #4 to parent,
    multidom@curved@edge=from (.#4) to (!u.parent anchor),
%<debug>    debug@multidom=Moving sub-tree by #2 and #3,
    before drawing tree={%
      for tree={x'+=#2,y'+=#3},
    },
  },
%    \end{macrocode}
% \end{fstyle}
% \begin{fstyle}{multidom@curved@edge}
%   Draw a curved edge from a child to its natural or additional parent.
%   Ultra simple.
%    \begin{macrocode}
  multidom@curved@edge/.style args={from (#1.#2) to (#3)}{%
    edge path'={(#1.#2) to [looseness=.5, out=#2] (#3)},
  },
%    \end{macrocode}
% \end{fstyle}
% \begin{fstyle}{other multidom parents}
%   Convenience wrapper in case many additional parents are required.
%    \begin{macrocode}
  other multidom parents/.style={%
    split={#1}{,}{multidom@aux},
  },
%    \end{macrocode}
% \end{fstyle}
% \begin{fstyle}{multidom prepend,multidom append}
%    \begin{macrocode}
  multidom prepend/.style n args=5{%
    multidom={prepend}{#1}{#2}{#3}{#4}{#5}%
  },
  multidom append/.style n args=5{%
    multidom={append}{#1}{#2}{#3}{#4}{#5}%
  },
%    \end{macrocode}
% \end{fstyle}
% Add code to default preamble to check for multi-dominance flags.
%
% Path here is based on builtin \pkg{forest} libraries, which should (hopefully?) hook into the same mechanisms, but this is not really documented??
%
% Dependence on another library is also not really documented \dots.
% It's not really clear to me whether other people are just not expected to write libraries \dots, but it is such a standard mechanism in \pgftikz, that would seem odd?
%    \begin{macrocode}
%<!debug>      libraries/ext.ling/defaults/.style={%
%<debug>      libraries/ext.ling-debug/defaults/.style={%
%<!debug>      libraries/ext.multi/defaults,
%<debug>      libraries/ext.multi-debug/defaults,
  },
%    \end{macrocode}
% \begin{fstyle}{debug@multidom,debug@multidom@register,debug@multidom@option}
%   Internal styles for debugging.
%   Should not be used directly, but may be applied by loading the debugging code.
%    \begin{macrocode}
%<debug>    debug@multidom/.code={%
%<debug>      \ExpandArgs {e} \typeout{[Forest ext.ling debug]:: \detokenize{#1}}%
%<debug>    },
%<debug>    debug@multidom@register/.code={%
%<debug>      \ExpandArgs {e} \typeout{[Forest ext.ling debug]:: \detokenize{#1}
%<debug>        = \foresteregister{#1}%
%<debug>      }%
%<debug>    },
%<debug>    debug@multidom@option/.code={%
%<debug>      \ExpandArgs {e} \typeout{[Forest ext.ling debug]:: \detokenize{#1}
%<debug>        = \foresteoption{#1}%
%<debug>      }%
%<debug>    },
%<debug>    debug multidom phantoms/.forward to=/forest/debug multi phantoms,
%    \end{macrocode}
% \end{fstyle}
% \begin{fstyle}{debug multidom phantoms}
%   Supply a code key as substitute for the boolean if the debugging code isn't loaded.
%    \begin{macrocode}
%<!debug>    debug multidom phantoms/.code={%
%<!debug>      \PackageWarning{forest-lib-ext.ling}{%
%<!debug>       You requested the style 'debug multidom phantoms', 
%<!debug>       but did not load the debugging code. 
%<!debug>       Either load 'ext.ling-debug' instead of 
%<!debug>       'ext.ling' or remove this style.%
%<!debug>     }%
%<!debug>    }, 
%    \end{macrocode}
% \end{fstyle}
%    \begin{macrocode}
}
%    \end{macrocode}
% \end{drop}
%</debug>
% ^^A >>> multidom
%
% ^^A <<< pretty nice empty nodes
% \begin{fstyle}{pretty nice empty nodes}
%   This is in the \pkg{ext.ling} library mostly because \texttt{nice empty nodes} is in the \pkg{linguistics} library and not because linguists are more picky about their empty nodes than anybody else.
% 
%   Is this even still useful?
% 
%   \texseans{717677} i gwestiwn \texseqn{717592}[argo] 
%    \begin{macrocode}
\forestset{%
  pretty nice empty nodes/.style={%
    for tree={%
      calign=fixed edge angles,
      parent anchor=children,
      delay={%
        if content={}{%
          inner sep=0pt,
          edge path'={(!u.parent anchor) -- (.children)},
          #1,
        }{},
      },
    },
  },
}
%    \end{macrocode}
% \end{fstyle}
% ^^A >>> pretty nice empty nodes
%</sty>
%^^A >>>
%
% ^^A \Finale
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
%^^A vim: et:tw=0:sw=2:ts=2:foldmethod=marker:fmr=<<<,>>>: