%%%% Copyright 2026 by Gerhard Schaden
%%%% Standalone reimplementation of the linguex user interface
%%%% (original linguex by Wolfgang Sternefeld; interlinear glossing
%%%%  interface modelled on cgloss4e by Hans-Peter Kolb & Craig Thiersch)
%%%% This program can be redistributed and/or modified under the terms
%%%% of the LaTeX Project Public License
\NeedsTeXFormat{LaTeX2e}[2020/10/01]% expl3 in kernel required
\ProvidesPackage{linguexx}[2026/07/30 Standalone linguistic examples, linguex-compatible interface v. 1.1]
%% v. 0.1: [legacy] option; empty \firstrefdash by default.
%% v. 0.2: tagging-safe under \DocumentMetadata (PDF tagging testphase):
%%         lists opened/closed through the environment interface; no TeX
%%         group around the example as a whole; explicit @endpe/text-unit
%%         cleanup after each example.  Labels set flush left in a
%%         \labelwidth box so the tagged block code does not re-box them
%%         flush right (which had shifted sub-labels right of the text
%%         margin).  Structure trees stay valid and geometry matches the
%%         untagged output, on all three engines, incl. footnote examples.
%%         Default \SubSubExlabelwidth reduced 1.9em->1.6em (sized for
%%         roman labels up to "vi."; equals \SubExlabelwidth), so the
%%         roman level no longer has a visibly larger label-to-text gap.
%% v. 0.3: PDF tagging objective 2 -- examples as proper list structure.
%%         Because examples are real \begin{list} environments, the tagged
%%         output already nests L > LI > Lbl > LBody with sub-levels as
%%         nested Ls; v0.3 additionally marks each example list ORDERED
%%         (/ListNumbering/Ordered) instead of the default label-less
%%         class.  Tag-guarded; no effect without active tagging.
%% v. 0.4: PDF tagging objective 3 -- spoken forms for judgment marks.
%%         Under active tagging each mark is wrapped in a Span carrying
%%         /Alt so a screen reader announces its meaning ("ungrammatical")
%%         rather than the glyph.  Defaults for * ? ?? ?* # % ; override
%%         via \DeclareJudgment[spoken=...] or \SetJudgmentSpoken.
%%         Tag-guarded; printed output and untagged runs are unchanged.
%% v. 0.5: fix an invalid PDF attribute value from v0.3.  Ordered example
%%         lists were routed through the block code's enumerate class,
%%         whose /ListNumbering value is /Ordered -- not one of the values
%%         the PDF spec allows, so validators reject it.  Each level now
%%         gets a valid class of its own: /Decimal for the number level,
%%         /LowerAlpha for letters, /LowerRoman for romans.  If the tagged
%%         list internal is unavailable the lists fall back to the default
%%         (valid) /None rather than the bad value.
%% v. 0.6: PDF tagging objective 4 -- interlinear glosses as structure.
%%         Each gloss column (an object word with its aligned glosses) is
%%         wrapped in a Span, so a screen reader reads and navigates the
%%         gloss word bundle by word bundle in object-then-gloss order
%%         instead of as loose text.  The paragraph mc is paused per
%%         column (\tag_mc_end_push:/..._begin_pop:) and each word gets
%%         its own mc under the column Span.  Tag-guarded; the printed
%%         grid and untagged output are unchanged.
%% v. 0.7: PDF tagging objective 5 -- language of a gloss tier.
%%         \GlossTierLang{tier}{code} records a language code for a tier;
%%         under tagging each word of that tier is wrapped in a Span with
%%         /Lang so a screen reader uses the right phonetics.  Tiers with
%%         no declared language are unchanged.  Tag-guarded.
%% v. 0.8: PDF tagging objective 6 -- Leipzig gloss abbreviations.
%%         \lpzg{sg} sets the abbreviation in small caps and, under
%%         tagging, wraps it in a Span carrying /E (expansion text) so a
%%         screen reader announces "singular" while print and copy keep
%%         SG.  Built-in standard Leipzig table, keyed by short form;
%%         \SetLeipzig{key}{expansion} extends/overrides; unknown keys
%%         print with no expansion.  Tag-guarded; self-contained.
%% v. 0.9: \lpzg accepts a whole compound label in one call (3sg.pst):
%%         split on periods, a leading person digit peeled off, each piece
%%         expanded and joined into one /E ("third person singular past").
%%         \GlossTierLang is now scoped: a document-wide default in the
%%         preamble, overridable per example by issuing it inside the
%%         example (local assignment, reverts afterwards).
%% v. 0.10: (reverted in 0.11) attempt to give \alt/\altg a spoken /Alt.
%% v. 0.11: revert the 0.10 \alt/\altg tagging.  Wrapping the alternatives
%%          formula in a Span carrying /Alt is invalid under PDF/UA-2 when
%%          the formula begins an example (a Span may not contain the
%%          Part/P that the math tagging then builds), and veraPDF rejects
%%          it.  \alt/\altg revert to the plain formula, which validates;
%%          giving them a spoken form needs the "positioning text" math
%%          interface and is deferred.
%% v. 0.12: remove \altg/\lxAltg (alternatives with translations).
%% v. 0.13: \alt rebuilt in text mode -- a tabular stack with a TikZ-drawn
%%          brace, no math and no amsmath, so the alternatives are ordinary
%%          tagged text.  Under tagging the stack is wrapped in a Span with a
%%          spoken /Alt ("A, B, or C", built with \text_purify:n).  Requires
%%          graphicx + tikz instead of amsmath.
%% v. 0.14: \altg/\lxAltg return, rebuilt in text mode.  Written twice in
%%          an interlinear gloss -- object words in the object line,
%%          glosses in the gloss line -- the two calls occupy the two
%%          tiers of one column and assemble a single paradigm: object
%%          stack, gloss stack to its right, braced on both sides and
%%          centred on the object/gloss midline.  Each call carries its
%%          own spoken /Alt under tagging; no math, so the PDF/UA-2
%%          failure that removed the old \altg does not recur.  Also:
%%          \alt now closes its stack with a right brace as well (the
%%          pre-0.13 look), and the TikZ brace direction is corrected --
%%          since 0.13 the brace was drawn mirrored.
%% v. 1.0: \alt/\lxAlt renamed to \altn/\lxAltn -- \alt collides with
%%          beamer, glossaries-extra, revtex/revsymb, tex4ht, and others;
%%          \altn is unclaimed.  \altg/\lxAltg unaffected (no collisions).
%% v. 1.1: \lpzglist -- the list of abbreviations the document actually
%%          uses, with full forms, sourced from every \lpzg/\lpzgadd call
%%          and customisable per list or document-wide; a real tagged
%%          list under tagging.  Phantom bracket alignment for interlinear
%%          glosses (opt-in via [phantomalign] or \GlossPhantomAlign):
%%          pads a gloss word by a \phantom the width of the object word's
%%          leading brackets/judgment marks, so real glyphs line up;
%%          \GlossPhantom{...} is the manual override.  Fix: \a-\f (the
%%          sub-example letters) now only mean "start/continue a
%%          sub-example" while an example is open; outside one they are
%%          left untouched, so \b{}/\c{}/\d{} accents, an
%%          inputenc-decomposed "ç", and hyperref's own bookmark-string
%%          handling of them all keep working in running text and
%%          section titles again (previously always clobbered under
%%          [lazy], the default).
%% Package options come in two independent groups.
%%
%% SYNTAX:
%%   [lazy]  (the default): the traditional linguex dot syntax --
%%           \ex., \a.-\f., \z., \exg. -- and nothing else.
%%   [gb4e]: only the gb4e environment syntax -- exe, xlist, \ex
%%           (without period, with optional bracketed judgment).  In
%%           this mode the letter commands \b., \c., \d. are never
%%           defined, so the kernel accent commands \b, \c, \d remain
%%           untouched and no hyperref workaround is needed.
%% Both may be requested together, [lazy,gb4e], for documents that
%% deliberately mix the syntaxes (this package's own manual does).
%%
%% DEFAULTS (lengths, dashes, sub-label delimiters):
%%   none (the default): this package's own defaults -- see
%%           \lx@defaults@lazy below.
%%   [legacy]: linguex's defaults, to the value -- see
%%           \lx@defaults@legacy below.  Nothing else changes: the
%%           engine, the error behaviour and the extensions are the
%%           same in both modes.  [legacy] is orthogonal to the syntax
%%           options, so [legacy,gb4e] is meaningful (gb4e syntax,
%%           linguex geometry), and [legacy] alone implies the dot
%%           syntax, exactly as [lazy] alone does.
\newif\iflx@lazy
\newif\iflx@gbfour
\newif\iflx@legacy
\newif\iflx@phantomalign
\DeclareOption{lazy}{\lx@lazytrue}
\DeclareOption{gb4e}{\lx@gbfourtrue}
\DeclareOption{legacy}{\lx@legacytrue}
\DeclareOption{phantomalign}{\lx@phantomaligntrue}
\DeclareOption*{\PackageWarning{linguexx}{Unknown option
  '\CurrentOption' ignored}}
\ProcessOptions\relax
\iflx@gbfour\else\lx@lazytrue\fi

\RequirePackage{graphicx}%          \scalebox etc.
\RequirePackage{tikz}%              drawn brace for \lxAltn (no math mode)
\usetikzlibrary{decorations.pathreplacing}
% The only other dependency is the expl3 programming layer, part of the
% LaTeX kernel since 2020.  In particular, ulem is NOT loaded: if you
% want struck-through alternatives (\sout inside \altn), load ulem
% yourself, with whatever options you prefer.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%  Counters and number formatting (linguex-compatible names)          %%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\newcounter{ExNo}
\newcounter{SubExNo}
\newcounter{SubSubExNo}
\newcounter{FnExNo}

% linguex resets ExNo at every \chapter in a class that has chapters.
% That is a numbering CONVENTION, not a bug, so [legacy] reproduces it;
% the default is continuous numbering through the document.
\iflx@legacy
  \@ifundefined{c@chapter}{}{\@addtoreset{ExNo}{chapter}}
\fi

% back-compat aliases (linguex spelt these with a prefix)
\let\Exarabic\arabic
\let\Exalph\alph
\let\Exroman\roman

% Reference dashes and sub-label delimiters.  Only the NAMES are reserved
% here; the values are set by the defaults block in the Layout section
% (\lx@defaults@lazy / \lx@defaults@legacy), so that both modes go through
% one place.  \firstrefdash separates number from letter in a reference,
% \secondrefdash letter from roman numeral: (12a-i) by default, (12-a-i)
% under [legacy].  The delimiters wrap the PRINTED sub-example labels:
% "a." and "i." by default, "a." and "(i)" under [legacy].
\newcommand\firstrefdash{}
\newcommand\secondrefdash{-}
\newcommand\SubExLBr{}
\newcommand\SubExRBr{.}
\newcommand\SubSubExLBr{}
\newcommand\SubSubExRBr{.}

% parenthesis suppression switch (v1 machinery, kept verbatim in spirit)
\newif\ifparens\parensfalse
\newcommand\theExLBr{\ifparens\else(\fi}
\newcommand\theExRBr{\ifparens\else)\fi}
\newcommand\theFnExLBr{\ifparens\else(\fi}
\newcommand\theFnExRBr{\ifparens\else)\fi}

% "am I in a footnote?" -- linguex's switch name kept for compatibility;
% TRUE means NOT in a footnote (sic, as in linguex)
\newif\if@noftnote\@noftnotetrue
\AtBeginDocument{%
  \let\lx@orig@footnotetext\@footnotetext
  \long\def\@footnotetext#1{\lx@orig@footnotetext{\@noftnotefalse#1}}}

\renewcommand{\theExNo}{\protect\theExLBr\arabic{ExNo}\protect\theExRBr}
\renewcommand{\theFnExNo}{\protect\theFnExLBr\roman{FnExNo}\protect\theFnExRBr}

\renewcommand{\theSubExNo}{%
  \hbox{\if@noftnote\protect\theExLBr\Exarabic{ExNo}\firstrefdash
      \Exalph{SubExNo}\protect\theExRBr
    \else
      \protect\theFnExLBr\Exroman{FnExNo}\firstrefdash%
      \Exalph{SubExNo}\protect\theFnExRBr
    \fi}}

\renewcommand{\theSubSubExNo}{%
  \hbox{\if@noftnote\protect\theExLBr%
          \Exarabic{ExNo}\firstrefdash\Exalph{SubExNo}\secondrefdash
             \Exroman{SubSubExNo}\protect\theExRBr%
    \else\protect\theFnExLBr\Exroman{FnExNo}\firstrefdash
              \Exalph{SubExNo}\secondrefdash\Exroman{SubSubExNo}\protect\theFnExRBr\fi}}

% hyperref anchor names (avoid the \protect-laden \the... expansions)
\def\theHExNo{lxex.\arabic{ExNo}}
\def\theHSubExNo{lxex.\arabic{ExNo}.\alph{SubExNo}}
\def\theHSubSubExNo{lxex.\arabic{ExNo}.\alph{SubExNo}.\arabic{SubSubExNo}}
\def\theHFnExNo{lxfnex.\arabic{FnExNo}}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%  Layout parameters                                                  %%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%% The geometry is the same in both modes -- each level reserves a label
%% box, the text margin of a level is the label box plus a gap, measured
%% from the margin of the level above -- but the two modes PARAMETRIZE it
%% differently, because linguex did:
%%
%%   default: the sub-levels are given by their LABEL WIDTHS
%%            (\SubExlabelwidth, \SubSubExlabelwidth), each followed by
%%            the shared gap \Exlabelsep;
%%   legacy:  the sub-levels are given by their TEXT MARGINS
%%            (\SubExleftmargin, \SubSubExleftmargin), the label being set
%%            flush left inside that margin with no gap, and the main
%%            \Exlabelwidth is recomputed for every example from the width
%%            of the number itself.
%%
%% All the lengths of both sets exist in both modes; only the ones its own
%% mode reads have any effect.  The equivalence is
%%   \SubExleftmargin = \SubExlabelwidth + \Exlabelsep.

\newlength{\Extopsep}
\newlength{\Exredux}
\newlength{\Exindent}
\newlength{\Exlabelwidth}
\newlength{\Exlabelsep}
% The sub-example label boxes are wider than the letters strictly need.
% The surplus is the room a hanging judgment falls into: the clear space
% left of the text is (labelwidth - width of the printed letter) +
% \Exlabelsep.  The defaults are chosen so that TWO marks (e.g. "??",
% "?*") fit without touching the letter; for three or more as a routine
% matter, widen these.
\newlength{\SubExlabelwidth}
\newlength{\SubSubExlabelwidth}
% linguex's names for the same two levels (see above)
\newlength{\SubExleftmargin}
\newlength{\SubSubExleftmargin}

% \Extopsep and \Exredux are the only lengths that depend on the font:
% they are set here (so that a \setlength in the PREAMBLE overrides them,
% which it cannot do in linguex) and re-derived \AtBeginDocument if -- and
% only if -- they still hold the value computed here, which catches the
% case of a font package that changes \baselineskip after we are loaded.
\newlength{\lx@auto@topsep}
\newlength{\lx@auto@redux}
\newcommand\lx@setskips{%
  \setlength{\Extopsep}{.66\baselineskip}%
  \setlength{\Exredux}{\lx@reduxfactor\baselineskip}%
  \setlength{\lx@auto@topsep}{\Extopsep}%
  \setlength{\lx@auto@redux}{\Exredux}}
\AtBeginDocument{%
  \ifdim\Extopsep=\lx@auto@topsep
    \ifdim\Exredux=\lx@auto@redux \lx@setskips \fi
  \fi}

%% ---- the two sets of defaults -------------------------------------------

\newcommand\lx@defaults@lazy{%
  \def\lx@reduxfactor{-.66}%
  \lx@setskips
  \setlength{\Exindent}{0pt}%
  \setlength{\Exlabelwidth}{2.6em}%
  \setlength{\Exlabelsep}{.6em}%
  \setlength{\SubExlabelwidth}{1.6em}%
  \setlength{\SubSubExlabelwidth}{1.6em}%
  \setlength{\SubExleftmargin}{\dimexpr\SubExlabelwidth+\Exlabelsep\relax}%
  \setlength{\SubSubExleftmargin}{\dimexpr\SubSubExlabelwidth+\Exlabelsep\relax}%
  \setlength{\JdgSep}{0.15em}%
  \def\firstrefdash{}%
  \def\secondrefdash{-}%
  \def\SubExLBr{}\def\SubExRBr{.}%
  \def\SubSubExLBr{}\def\SubSubExRBr{.}%
  \def\GlossSep{.5em plus .3em minus .1em}}

%% linguex's defaults, to the value: \Exlabelsep 1.3em, \Exindent 0pt,
%% \SubExleftmargin 2em, \SubSubExleftmargin 2.4em, \Extopsep
%% .66\baselineskip, \Exredux -\baselineskip, and a main label box whose
%% width is that of the current number, padded to the next digit (so "(1)"
%% sits in a two-digit box).  Judgments are flush against the text
%% (\JdgSep 0pt), sub-sub-examples print as "(i)", and references are
%% (12-a), (12-a-i).  \GlossSep approximates cgloss4e's word spacing (an
%% interword space plus its \glossglue), which is tighter than ours.
\newcommand\lx@defaults@legacy{%
  \def\lx@reduxfactor{-1}%
  \lx@setskips
  \setlength{\Exindent}{0pt}%
  \setlength{\Exlabelsep}{1.3em}%
  \setlength{\SubExleftmargin}{2em}%
  \setlength{\SubSubExleftmargin}{2.4em}%
  \setlength{\SubExlabelwidth}{\dimexpr\SubExleftmargin-\Exlabelsep\relax}%
  \setlength{\SubSubExlabelwidth}{\dimexpr\SubSubExleftmargin-\Exlabelsep\relax}%
  \setlength{\Exlabelwidth}{4em}% recomputed per example; see \lx@calc@Exlabelwidth
  \setlength{\JdgSep}{0pt}%
  \def\firstrefdash{-}%
  \def\secondrefdash{-}%
  \def\SubExLBr{}\def\SubExRBr{.}%
  \def\SubSubExLBr{(}\def\SubSubExRBr{)}%
  \def\GlossSep{.33em plus .4em minus .2em}}

\iflx@legacy
  \let\resetExdefaults\lx@defaults@legacy
\else
  \let\resetExdefaults\lx@defaults@lazy
\fi
% \resetExdefaults is CALLED at the end of the package, once every length
% it touches has been declared; the user may call it again at any point to
% return to the defaults of the mode in force.

%% ---- the geometry hooks -------------------------------------------------
%% Each level's list declaration calls one of these; they are the ONLY
%% place where the two parameter sets differ.

% width of the narrowest digit, as linguex measured it (fonts in which the
% digits differ in width would otherwise pad inconsistently)
\newlength{\lx@digitwd}
\newlength{\lx@mindigitwd}
\newlength{\lx@currentlabel}
\newlength{\lx@padded}
\def\lx@minwidth#1{\settowidth{\lx@digitwd}{#1}%
  \ifdim\lx@digitwd<\lx@mindigitwd \lx@mindigitwd\lx@digitwd \fi}
% \Exlabelwidth := width of the smallest n-digit box (n = 2,3,4) that the
% current label fits INSIDE; if it fits none, its own width.  This is
% linguex's rule, and the reason a one-digit example number sits in a box
% wide enough for two: the numbering does not shift the text as it grows.
\def\lx@calc@Exlabelwidth{%
  \settowidth{\lx@mindigitwd}{0}%
  \lx@minwidth{1}\lx@minwidth{2}\lx@minwidth{3}\lx@minwidth{4}%
  \lx@minwidth{5}\lx@minwidth{6}\lx@minwidth{7}\lx@minwidth{8}%
  \lx@minwidth{9}%
  \settowidth{\lx@currentlabel}{\lx@itemlabel}%
  \Exlabelwidth\lx@currentlabel
  \settowidth{\lx@padded}{\theExLBr\hbox to 4\lx@mindigitwd{}\theExRBr}%
  \ifdim\lx@currentlabel<\lx@padded \Exlabelwidth\lx@padded \fi
  \settowidth{\lx@padded}{\theExLBr\hbox to 3\lx@mindigitwd{}\theExRBr}%
  \ifdim\lx@currentlabel<\lx@padded \Exlabelwidth\lx@padded \fi
  \settowidth{\lx@padded}{\theExLBr\hbox to 2\lx@mindigitwd{}\theExRBr}%
  \ifdim\lx@currentlabel<\lx@padded \Exlabelwidth\lx@padded \fi}

\iflx@legacy
  % main level: label box recomputed from the number; text margin
  % \Exindent + \Exlabelwidth + \Exlabelsep, as in the default mode
  \def\lx@geom@main{\lx@calc@Exlabelwidth
    \labelwidth\Exlabelwidth \labelsep\Exlabelsep
    \leftmargin\dimexpr\Exindent+\Exlabelwidth+\Exlabelsep\relax
    \if@noftnote\else\addtolength{\topsep}{-.5\topsep}\fi}
  % sub-levels: the text margin IS the parameter, the label sits flush
  % left inside it
  \def\lx@geom@sub{\leftmargin\SubExleftmargin
    \labelwidth\SubExleftmargin \labelsep\z@ \topsep.3\Extopsep}
  \def\lx@geom@subsub{\leftmargin\SubSubExleftmargin
    \labelwidth\SubSubExleftmargin \labelsep\z@ \topsep\z@}
\else
  \def\lx@geom@main{%
    \lx@ol@set{lxOLdecimal}%
    \labelwidth\Exlabelwidth \labelsep\Exlabelsep
    \leftmargin\dimexpr\Exindent+\Exlabelwidth+\Exlabelsep\relax}
  \def\lx@geom@sub{\lx@ol@set{lxOLalpha}%
    \labelwidth\SubExlabelwidth \labelsep\Exlabelsep
    \leftmargin\dimexpr\SubExlabelwidth+\Exlabelsep\relax \topsep\z@}
  \def\lx@geom@subsub{\lx@ol@set{lxOLroman}%
    \labelwidth\SubSubExlabelwidth \labelsep\Exlabelsep
    \leftmargin\dimexpr\SubSubExlabelwidth+\Exlabelsep\relax \topsep\z@}
\fi

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%  Judgment auto-detection (* ? \# \%) -- replaces linguex's          %%%%
%%%%  hardcoded catcode tokenizer                                        %%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%% A judgment typed at the very start of an example or sub-example
%% (\ex. *Sentence / \a. ??\%Sentence) is collected greedily and set
%% flush right in the LABEL area, so example texts align whether or not
%% they carry a judgment.  Recognized: the characters * and ? and the
%% control sequences \# and \%.  Anything else: use \jdg{...}, which
%% works anywhere and takes arbitrary marks.

\ExplSyntaxOn
\tl_new:N \l__lx_judge_tl
\tl_new:N \l__lx_judge_cont_tl

% scan judgments, then execute #1 (the collected marks are in
% \lx@judgeprint; \lx@emitjudge hangs them via \jdg if nonempty)
\cs_new_protected:Npn \lx@scanjudgeto #1
  {
    \tl_clear:N \l__lx_judge_tl
    \tl_set:Nn \l__lx_judge_cont_tl {#1}
    \__lx_judge_loop:
  }
\cs_new_protected:Npn \lx@scanjudge
  { \lx@scanjudgeto { \lx@makeitem } }
\cs_new_protected:Npn \__lx_judge_loop:
  {
    \peek_remove_spaces:n
      {
        \peek_charcode_remove:NTF *
          { \tl_put_right:Nn \l__lx_judge_tl {*} \__lx_judge_loop: }
          {
        \peek_charcode_remove:NTF ?
          { \tl_put_right:Nn \l__lx_judge_tl {?} \__lx_judge_loop: }
          {
        \peek_meaning_remove:NTF \#
          { \tl_put_right:Nn \l__lx_judge_tl {\#} \__lx_judge_loop: }
          {
        \peek_meaning_remove:NTF \%
          { \tl_put_right:Nn \l__lx_judge_tl {\%} \__lx_judge_loop: }
          { \tl_use:N \l__lx_judge_cont_tl }
          } } }
      }
  }
\cs_new:Npn \lx@judgeprint { \tl_use:N \l__lx_judge_tl }
\cs_new_protected:Npn \lx@setjudge #1
  { \tl_set:Nn \l__lx_judge_tl {#1} }

%% Objective 3: spoken alternatives for judgment marks.  Each mark is a
%% symbol whose meaning a screen reader cannot infer ("asterisk"); under
%% PDF tagging we wrap it in a Span carrying /Alt so it is announced
%% ("ungrammatical").  \g_lx_judge_alt_prop maps a mark string to its
%% spoken form; defaults follow standard usage and can be overridden or
%% extended with \DeclareJudgment[spoken=...] or \SetJudgmentSpoken.
\prop_new:N \g_lx_judge_alt_prop
\prop_gput:Nnn \g_lx_judge_alt_prop {*}   {ungrammatical}
\prop_gput:Nnn \g_lx_judge_alt_prop {?}   {questionable}
\prop_gput:Nnn \g_lx_judge_alt_prop {??}  {highly~questionable}
\prop_gput:Nnn \g_lx_judge_alt_prop {?*}  {extremely~degraded}
\prop_gput:Nnn \g_lx_judge_alt_prop {*?}  {extremely~degraded}
\prop_gput:Nnn \g_lx_judge_alt_prop {\#}  {infelicitous}
\prop_gput:Nnn \g_lx_judge_alt_prop {\%}  {grammatical~for~some~speakers}
\tl_new:N \l__lx_judge_alt_tl

\cs_new_protected:Npn \lx@judge@setalt #1#2
  { \prop_gput:Nnn \g_lx_judge_alt_prop {#1} {#2} }

%% Hang a judgment mark (#2) to the left; when tagging is active and a
%% spoken form (#1) is non-blank, wrap the mark in a Span with /Alt so it
%% is read aloud as #1.  Otherwise typeset the mark exactly as before, so
%% untagged output and non-tagging engines are unaffected.
%% \lx@makeitem calls \lx@emitjudge (hence this) as the very FIRST thing
%% after \item, i.e. at the start of a fresh list-item paragraph.  At that
%% point the kernel's own paragraph-tagging may already have an MC span
%% open for the not-yet-shown P; opening our Span's struct/MC directly, as
%% earlier versions did, nested our BDC inside that still-open one without
%% suspending it ("nested marked content found" / "no mc to end", and a
%% veraPDF untagged-content failure once that P's real MC never got
%% closed).  \tag_mc_end_push:/\tag_mc_begin_pop:n{} -- the same idiom
%% \lpzg and the gloss column code use -- suspends the ambient MC first.
\cs_new_protected:Npn \lx@hangjudge #1#2
  {
    \leavevmode
    \llap
      {
        \tl_if_blank:nTF {#1}
          { #2 }
          {
            \cs_if_exist:NTF \tag_struct_begin:n
              {
                \tag_if_active:TF
                  {
                    \tag_mc_end_push:
                    \tag_struct_begin:n { tag = Span , alt = {#1} }
                    \tag_mc_begin:n { tag = Span }
                    #2
                    \tag_mc_end:
                    \tag_struct_end:
                    \tag_mc_begin_pop:n {}
                  }
                  { #2 }
              }
              { #2 }
          }
        \hskip \JdgSep
      }
  }
\cs_new_protected:Npn \lx@emitjudge
  {
    \tl_if_empty:NF \l__lx_judge_tl
      {
        \tl_set:Ne \l__lx_judge_alt_tl
          { \prop_item:Ne \g_lx_judge_alt_prop { \tl_to_str:N \l__lx_judge_tl } }
        \exp_args:NV \lx@hangjudge \l__lx_judge_alt_tl { \lx@judgeprint }
      }
  }
\ExplSyntaxOff

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%  The example machinery: \ex. \a. \b. ... , blank-line terminated    %%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%% Architecture: \ex. is a \par-delimited macro, exactly as in linguex --
%% that is what makes "blank line ends the example" work.  BUT unlike
%% linguex, the entire body is grabbed as one argument, so all list
%% opening and closing happens inside a single macro invocation:
%%   \ex.  ->  \begingroup + open the main list  [process body]
%%             [close open sublists] + close the main list + \endgroup
%% Sub-example depth is tracked in a count register that is only ever
%% advanced INSIDE the group opened for the new sublevel, so leaving the
%% group automatically pops the depth: the grouping structure itself is
%% the stack, and global drift (linguex's ExDepth disease) is
%% structurally impossible.
%%
%% Semantics kept from linguex: \a. always opens a NEW, deeper level
%% (first level: letters, second: roman); \b. \c. \d. \e. \f. are
%% interchangeable "next item at current level" commands (the printed
%% letter comes from the counter, not the command name).  Two sublevels
%% maximum.  \ex.[custom] sets a custom label without stepping the
%% counter.  Inside footnotes, examples number (i), (ii), ... on the
%% FnExNo counter automatically.
%%
%% NOT carried over from linguex (deliberately): embedded examples
%% (\ex. inside \a.) and the \exi./\ai. index variants.

\newcount\lx@subdepth

%% The example body is collected TOKEN BY TOKEN (expl3 peek_analysis),
%% not grabbed as a \par-delimited argument.  Collection stops, at brace
%% depth 0, at the first of:
%%   - a \par token (i.e. the blank line, as under linguex);
%%   - \z. (early termination; the rest of the stream continues as
%%     ordinary text, so no blank line is needed after it);
%%   - a structural boundary: an unmatched \end{...}, \endgroup, or
%%     group-end token.  The boundary token is put back, so
%%     "\ex. Text\end{frame}" simply works.
%% \begin{...}/\end{...} and \begingroup/\endgroup pairs INSIDE the body
%% are counted, so environments inside examples are unaffected.  Brace
%% groups are collected whole; a \par inside braces is therefore legal
%% (it was an error under the old grab).  \z. and the terminating \par
%% are only recognized at brace depth 0.
%% \ex dispatches on what follows: a period gives the classic dot
%% syntax; anything else is the gb4e item form.  Each branch is defined
%% by the mode in force, with an instructive error where a syntax is
%% not loaded.
\newif\iflx@inexe
\def\ex{\@ifnextchar.{\lx@ex@dot}{\lx@ex@nodot}}
\iflx@lazy
  \def\lx@ex@dot.{\lx@collectbody}
\else
  \def\lx@ex@dot.{%
    \PackageError{linguexx}{The dot syntax (\string\ex.) is not
      available under [gb4e]}{Use \string\ex\space inside
      \string\begin{exe} ... \string\end{exe}, or load linguexx
      without options (or with [lazy]) for the dot syntax.}}
\fi
\iflx@gbfour
  \def\lx@ex@nodot{%
    \iflx@inexe
      \expandafter\lx@gbex
    \else
      \lx@gbex@err
      \expandafter\lx@gbex
    \fi}
  \def\lx@gbex@err{%
    \PackageError{linguexx}{\string\ex\space outside exe/xlist}{Put
      \string\ex\space inside \string\begin{exe} ...
      \string\end{exe}\iflx@lazy, or write \string\ex. (with the
      period) for the dot syntax\fi.}}
\else
  \def\lx@ex@nodot{%
    \PackageError{linguexx}{\string\ex\space must be followed by a
      period}{Write \string\ex. -- or load
      \string\usepackage[gb4e]{linguexx} for the environment
      syntax.}}
\fi

% gb4e item form: \ex[judgment]{text} or plain \ex text
\def\lx@gbex{\@ifnextchar[{\lx@gbex@opt}{\lx@gbex@plain}}
\def\lx@gbex@plain{%
  \ifcase\lx@subdepth
    \let\lx@donext\lx@mainitem
  \or \let\lx@donext\lx@subitem
  \or \let\lx@donext\lx@subsubitem
  \fi
  \lx@donext}
\long\def\lx@gbex@opt[#1]#2{%
  \ifcase\lx@subdepth
    \lx@main@core
  \or \lx@subitem@core
  \or \lx@subsubitem@core
  \fi
  \lx@setjudge{#1}%
  \lx@makeitem#2}

\ExplSyntaxOn
\tl_new:N \l__lx_body_tl
\tl_new:N \l__lx_body_tmp_tl
\seq_new:N \l__lx_body_stack_seq
\int_new:N \l__lx_body_env_int
\int_new:N \l__lx_body_grp_int
\int_new:N \l__lx_body_col_int

\cs_new_protected:Npn \lx@collectbody
  {
    \tl_clear:N \l__lx_body_tl
    \seq_clear:N \l__lx_body_stack_seq
    \int_zero:N \l__lx_body_env_int
    \int_zero:N \l__lx_body_grp_int
    \int_zero:N \l__lx_body_col_int
    \__lx_body_loop:
  }
\cs_new_protected:Npn \__lx_body_loop:
  {
    \peek_analysis_map_inline:n
      {
        \int_case:nnF { "##3 }
          {
            { 1 } { \seq_push:NV \l__lx_body_stack_seq \l__lx_body_tl
                    \tl_clear:N \l__lx_body_tl }
            { 2 } { \seq_pop:NNTF \l__lx_body_stack_seq \l__lx_body_tmp_tl
                      {
                        \tl_put_right:Ne \l__lx_body_tmp_tl
                          { { \exp_not:V \l__lx_body_tl } }
                        \tl_set_eq:NN \l__lx_body_tl \l__lx_body_tmp_tl
                      }
                      { \peek_analysis_map_break:n
                          { \lx@body@info{group~end}\lx@runbody \egroup } }
                  }
          }
          {
            \bool_lazy_and:nnTF
              { \int_compare_p:nNn {##2} = { -1 } }
              { \seq_if_empty_p:N \l__lx_body_stack_seq }
              { \__lx_body_cs:n {##1} }
              { \tl_put_right:Ne \l__lx_body_tl {##1} }
          }
      }
  }
% control-sequence dispatch at brace depth 0.  Terminators: \par;
% a nested \ex./\exg. (embedded examples are unsupported, so this is a
% forgotten blank line: treat as boundary); unmatched \end, \endgroup,
% \color@endgroup (footnote machinery), each pair-counted against its
% opener inside the body.  \z is NOT handled here: it is an ordinary
% body macro, interpreted at typesetting time (see \lx@zpop below).
\cs_new_protected:Npn \__lx_body_cs:n #1
  {
    \str_if_eq:eeTF {#1} { \exp_not:N \par }
      { \peek_analysis_map_break:n { \lx@runbody } }
      {
    \str_if_eq:eeTF {#1} { \exp_not:N \ex }
      { % inside a \begin{...}\end{...} pair within the body (an xlist,
        % say), \ex is a legitimate item command and is collected; at
        % environment depth 0 it can only be a forgotten blank line
        \int_compare:nNnTF { \l__lx_body_env_int } > { 0 }
          { \tl_put_right:Ne \l__lx_body_tl {#1} }
          { \peek_analysis_map_break:n
              { \lx@body@info{\string\ex.}\lx@runbody \ex } } }
      {
    \str_if_eq:eeTF {#1} { \exp_not:N \exg }
      { \int_compare:nNnTF { \l__lx_body_env_int } > { 0 }
          { \tl_put_right:Ne \l__lx_body_tl {#1} }
          { \peek_analysis_map_break:n
              { \lx@body@info{\string\exg.}\lx@runbody \exg } } }
      {
    \str_if_eq:eeTF {#1} { \exp_not:N \begin }
      { \int_incr:N \l__lx_body_env_int
        \tl_put_right:Ne \l__lx_body_tl {#1} }
      {
    \str_if_eq:eeTF {#1} { \exp_not:N \end }
      { \int_compare:nNnTF { \l__lx_body_env_int } > { 0 }
          { \int_decr:N \l__lx_body_env_int
            \tl_put_right:Ne \l__lx_body_tl {#1} }
          { \peek_analysis_map_break:n
              { \lx@body@info{\string\end}\lx@runbody \end } } }
      {
    \str_if_eq:eeTF {#1} { \exp_not:N \begingroup }
      { \int_incr:N \l__lx_body_grp_int
        \tl_put_right:Ne \l__lx_body_tl {#1} }
      {
    \str_if_eq:eeTF {#1} { \exp_not:N \endgroup }
      { \int_compare:nNnTF { \l__lx_body_grp_int } > { 0 }
          { \int_decr:N \l__lx_body_grp_int
            \tl_put_right:Ne \l__lx_body_tl {#1} }
          { \peek_analysis_map_break:n
              { \lx@body@info{\string\endgroup}\lx@runbody \endgroup } } }
      {
    \str_if_eq:eeTF {#1} { \exp_not:N \color@begingroup }
      { \int_incr:N \l__lx_body_col_int
        \tl_put_right:Ne \l__lx_body_tl {#1} }
      {
    \str_if_eq:eeTF {#1} { \exp_not:N \color@endgroup }
      { \int_compare:nNnTF { \l__lx_body_col_int } > { 0 }
          { \int_decr:N \l__lx_body_col_int
            \tl_put_right:Ne \l__lx_body_tl {#1} }
          { \peek_analysis_map_break:n
              { \lx@body@info{\string\color@endgroup}\lx@runbody \color@endgroup } } }
      { \tl_put_right:Ne \l__lx_body_tl {#1} }
      } } } } } } } }
  }
\cs_new_protected:Npn \lx@runbody
  { \exp_args:NV \lx@run@ex \l__lx_body_tl }
\ExplSyntaxOff

\def\lx@body@info#1{%
  \PackageInfo{linguexx}{Example terminated by structural boundary (#1)}}

%% \lx@mainlist is called AFTER \lx@itemlabel has been fixed (either from
%% the counter or from \ex.[custom]), because under [legacy] the width of
%% the label box is derived from the label itself.  \topsep is set before
%% \lx@geom@main, which may modify it (halved in footnotes, under legacy).
%%
%% Lists are opened and closed through the ENVIRONMENT interface
%% (\begin{list}...\end{list}) rather than the command pair
%% \list...\endlist.  The two are equivalent on a classic engine, but
%% under the tagged PDF code (\DocumentMetadata testphase "block") the
%% environment is the supported interface: part of its state restoration
%% is keyed to the environment hooks, which never fire in command-form
%% use, and the resulting imbalance corrupts the structure tree (visible
%% with an example inside a footnote).  Funnelling every open and close
%% through the two macros below keeps that decision in one place.
%% Example lists are semantically ordered.  PDF's /ListNumbering has a
%% fixed set of valid values (Decimal, LowerAlpha, LowerRoman, ...);
%% "Ordered" is NOT one of them, so routing through the block code's
%% enumerate class (whose value is /Ordered) is rejected by validators.
%% Instead we define one valid attribute class per level and hand it to
%% the list's structure element.  \lx@ol@class carries the class for the
%% list about to open; a guarded patch of the block list-begin applies it
%% and clears it.  If that internal ever disappears the lists simply keep
%% the block's default class (/None) --- still valid, never /Ordered.
\ExplSyntaxOn
\tl_new:N \lx@ol@class
\cs_new_protected:Npn \lx@ol@set #1 { \tl_set:Nn \lx@ol@class {#1} }
\AddToHook{begindocument}
  {
    \cs_if_exist:NT \tagpdfsetup
      {
        \tagpdfsetup
          {
            newattribute = { lxOLdecimal } { /O /List /ListNumbering /Decimal } ,
            newattribute = { lxOLalpha   } { /O /List /ListNumbering /LowerAlpha } ,
            newattribute = { lxOLroman   } { /O /List /ListNumbering /LowerRoman } ,
          }
      }
    \cs_if_exist:NT \__block_list_begin:
      {
        \cs_gset_eq:NN \lx@orig@list@begin: \__block_list_begin:
        \cs_gset:Npn \__block_list_begin:
          {
            \tl_if_empty:NF \lx@ol@class
              {
                \tl_set_eq:NN \l__tag_L_attr_class_tl \lx@ol@class
                \tl_clear:N \lx@ol@class
              }
            \lx@orig@list@begin:
          }
      }
  }
\ExplSyntaxOff
\def\lx@openlist#1{\begin{list}{}{#1}}
\def\lx@closelist{\end{list}}
\def\lx@mainlist{%
  \lx@openlist{\topsep\Extopsep
     \lx@geom@main
     \itemindent\z@ \listparindent\z@ \parsep\z@ \itemsep\z@
     \partopsep\z@ \parskip\z@
     \let\makelabel\lx@flushlabel}}

%% In the exe environment the list opens before any item exists, so the
%% label the width is derived from is the one the NEXT \ex will print.
\def\lx@guesslabel{%
  \if@noftnote
    \def\lx@itemlabel{\theExLBr\the\numexpr\value{ExNo}+1\relax\theExRBr}%
  \else
    \def\lx@itemlabel{\theFnExLBr
      \romannumeral\numexpr\value{FnExNo}+1\relax\theFnExRBr}%
  \fi}

%% No TeX group wraps the example as a whole: the list environment's own
%% group scopes everything set after the list opens, and wrapping the
%% environment in one extra group is exactly the pattern that trips the
%% text-unit accounting of the 2023 latex-lab "block" tagging code when
%% the example sits in a footnote.  What used to rely on that group is
%% now handled explicitly: \lx@inexample is reset in \lx@bodyend, and
%% \@currentlabel/\@currentHref (set locally by \refstepcounter BEFORE
%% the list opens, because [legacy] sizes the label box off the label)
%% are saved here and restored in \lx@bodyend, so a \label after the
%% example still refers to whatever preceded it.
\long\def\lx@run@ex#1{%
  \ifdim\lastskip=\Extopsep\vspace{\Exredux}\fi
  \lx@subdepth\z@
  \setcounter{SubExNo}{0}\setcounter{SubSubExNo}{0}%
  \let\lx@saved@currentlabel\@currentlabel
  \ifdefined\@currentHref
    \let\lx@saved@currentHref\@currentHref
  \fi
  \lx@inexampletrue
  \lx@letters@on
  \lx@exstart#1\lx@bodyend}

% closes the example: all open sublists, the main list, the group.
% Doubles as the sentinel marking the end of the grabbed body, which is
% what allows \z. to terminate the example early (see below).
\def\lx@bodyend{%
  \lx@closesubs
  \lx@closelist
  \lx@example@cleanup\ignorespacesafterend}
%% Under the tagged-PDF testphase code, the block layer wraps top-level
%% blocks in a "text-unit" structure element and defers its close to the
%% @endpe continuation paragraph.  Since the cleanup above cancels that
%% continuation, it must also perform the close the continuation's
%% para/end hook would have performed -- the same two operations, taken
%% from tagpdf's own end plug.  The internal names are deliberately
%% existence-guarded: this compensation is matched to the current
%% testphase internals and degrades to a no-op if they change.
\ExplSyntaxOn
\cs_new_protected:Npn \lx@tag@close@textunit
  {
    \cs_if_exist:NT \tag_if_active:T
      { \tag_if_active:T
          { \cs_if_exist:NT \__tag_gincr_para_main_end_int:
              { \__tag_gincr_para_main_end_int: \tag_struct_end: } } }
  }
\ExplSyntaxOff
\def\lx@example@cleanup{%
  \lx@inexamplefalse
  \lx@letters@off
  % The list's \end arms the "continue the paragraph" dance (@endpe +
  % an \everypar that clears it).  Our semantics is the opposite: a
  % blank line after an example starts a NEW, indented paragraph
  % (same-line continuation is handled explicitly by \z.).  Clear BOTH
  % halves of the dance, the way the kernel's own \everypar token
  % would: clearing only one of them is what desynchronises the tagged
  % text-unit bookkeeping.
  \if@endpe\everypar{}\@endpefalse\lx@tag@close@textunit\fi
  \let\@currentlabel\lx@saved@currentlabel
  \ifdefined\lx@saved@currentHref
    \let\@currentHref\lx@saved@currentHref
  \fi}

%% \lx@exstart@* : label, THEN list, THEN item (the order matters under
%% [legacy], where the list geometry is read off the label).
%% \lx@mainitem is the same thing minus the list, for an item inside an
%% exe environment, whose list is already open.
\def\lx@exstart{\@ifnextchar[{\lx@exstart@opt}{\lx@exstart@normal}}
\def\lx@exstart@opt[#1]{\def\lx@itemlabel{#1}\lx@mainlist\lx@scanjudge}
\def\lx@main@core{%
  \if@noftnote
    \refstepcounter{ExNo}\def\lx@itemlabel{\theExNo}%
  \else
    \refstepcounter{FnExNo}\def\lx@itemlabel{\theFnExNo}%
  \fi}
\def\lx@exstart@normal{\lx@main@core\lx@mainlist\lx@scanjudge}
\def\lx@mainitem{\lx@main@core\lx@scanjudge}

% the label box: number flush left; an auto-detected judgment is hung
% into the margin at the text edge via \jdg's zero-width \llap, so
% example texts align whether or not they carry a judgment, at every
% nesting level and for marks of any width.  The kernel \item is used
% under a saved name, because the xlist environment binds \item to the
% sub-example machinery locally.
\let\lx@kernel@item\item
\AtBeginDocument{\let\lx@kernel@item\item}
%% The label is set flush left in a box of exactly \labelwidth.  Forcing
%% the width (rather than the older trick of a trailing \hfil in a
%% natural-width label) is what makes flush-left survive PDF tagging: the
%% latex-lab block code re-boxes any label narrower than \labelwidth to
%% \labelwidth using its own alignment, which defaults to flush RIGHT; a
%% label that already fills \labelwidth is left untouched.  Classic
%% (untagged) output is identical.
\def\lx@flushlabel#1{\makebox[\labelwidth][l]{#1}}
\def\lx@makeitem{\lx@kernel@item[\lx@itemlabel]\lx@emitjudge\ignorespaces}

%% sub-examples ------------------------------------------------------------
%% \a. pushes a level; the depth advance happens INSIDE the new group.
%%
%% \a \b \c \d \e \f mean "start/continue a sub-example" (via a literal
%% "." right after) ONLY while an example is open (\iflx@inexample);
%% outside one they are left COMPLETELY untouched, so \c{c}, an
%% inputenc-decomposed "ç", or hyperref's own PU-encoding redefinition of
%% \b/\c/\d for its bookmark strings all keep working in a \section
%% title or anywhere else in running text, exactly as if linguexx were
%% not loaded there.  This is a plain \let swap at the example's own
%% start/end (\lx@run@ex / \lx@example@cleanup, see \lx@letters@on/@off
%% below), not a permanent global redefinition with a runtime fallback:
%% an earlier version peeked at the next token via \@ifnextchar to
%% decide whether to dispatch or fall back to the original accent, and
%% that broke under hyperref, which rebuilds bookmark strings by fully
%% \edef-expanding the title -- \futurelet-based lookahead is not
%% edef-safe. Scoping the redefinition itself to the example's lifetime
%% sidesteps the problem instead of working around it: outside an
%% example \c is never anything but whatever it would otherwise be, so
%% no edef-unsafe code ever runs on it.
\def\lx@dot@a.{\lx@subpush}
\def\lx@dot@b.{\lx@subnext}
\def\lx@dot@c.{\lx@subnext}
\def\lx@dot@d.{\lx@subnext}
\def\lx@dot@e.{\lx@subnext}
\def\lx@dot@f.{\lx@subnext}
%% Saves whatever \a-\f mean RIGHT BEFORE the example starts (not a
%% fixed original captured once at package load) and restores exactly
%% that afterward: correct regardless of load order relative to
%% hyperref, and safe even if something else redefines these letters
%% between two examples in the same document.  Examples do not nest
%% (see \lx@collectbody above), so one save slot per letter is enough.
\def\lx@letters@on{%
  \let\lx@saved@a\a \let\lx@saved@b\b \let\lx@saved@c\c
  \let\lx@saved@d\d \let\lx@saved@e\e \let\lx@saved@f\f
  \let\a\lx@dot@a \let\b\lx@dot@b \let\c\lx@dot@c
  \let\d\lx@dot@d \let\e\lx@dot@e \let\f\lx@dot@f}
\def\lx@letters@off{%
  \let\a\lx@saved@a \let\b\lx@saved@b \let\c\lx@saved@c
  \let\d\lx@saved@d \let\e\lx@saved@e \let\f\lx@saved@f}
\def\lx@assert@letters{%
  \def\z.{\lx@zpop}%
  \def\exg.{\ex.\lx@glosshead}%
  \def\ag.{\a.\lx@glosshead}%
  \def\bg.{\b.\lx@glosshead}%
  \def\cg.{\c.\lx@glosshead}%
  \def\dg.{\d.\lx@glosshead}%
  \def\eg.{\e.\lx@glosshead}%
  \def\fg.{\f.\lx@glosshead}}
\iflx@lazy
  \lx@assert@letters
  \AtBeginDocument{\lx@assert@letters}
\fi
% Under [gb4e] alone, \lx@assert@letters is never called and
% \lx@letters@on/@off (only ever invoked from \lx@run@ex, itself only
% reachable through the dot syntax) never run: \z., the glossed
% shorthands, and \a.-\f. do not exist, and the kernel accents \b, \c,
% \d (and hyperref's use of them) stay untouched everywhere, exactly as
% before.

%% \z. pops exactly ONE level, counting the surrounding prose as the
%% outermost level: from the roman level it returns to the letters (a
%% following \b. continues there); from the LETTER level, or in an
%% example without open sub-examples, it ENDS the example.  Consecutive
%% \z.'s therefore pop successively out of the example.  The rest of
%% the body after an example-ending \z. is reinjected after the close
%% (grabbed up to the \lx@bodyend sentinel): on the same line it is a
%% flush-left continuation, after a blank line an ordinary indented
%% paragraph.  \z. is interpreted at typesetting time and must stand at
%% brace depth 0 of the body; outside an example it is a package error.
\newif\iflx@inexample
\def\lx@zpop{%
  \iflx@inexample
    \expandafter\lx@zpop@i
  \else
    \expandafter\lx@zpop@err
  \fi}
\def\lx@zpop@i{%
  \ifnum\lx@subdepth>\@ne
    \lx@closelist\endgroup
  \else
    \expandafter\lx@zexit
  \fi}
% Text on the same line as a main-level \z. is a CONTINUATION: it is set
% flush left under the example (no \parindent), separated from it by the
% example's normal bottom space, and closed with \par (the source's own
% terminating \par was consumed as the collection delimiter).  If the
% rest is blank -- i.e. \z. is followed by one or more empty lines --
% nothing is reinjected, and the next source paragraph is an ordinary,
% class-indented paragraph.
\ExplSyntaxOn
\cs_new_protected:Npn \lx@zexit #1 \lx@bodyend
  {
    \lx@bodyend
    \tl_if_blank:nF {#1} { \noindent \ignorespaces #1 \par }
  }
\ExplSyntaxOff
\def\lx@zpop@err{%
  \PackageError{linguexx}{\string\z. outside an example}%
    {\string\z. closes one sub-example level, or ends the example when
     at its main level.}}

%% \exg. / \ag. ... \fg. : glossed shorthands, expanding to
%% \ex. \gll resp. \a. \gll etc., with judgment detection re-run in
%% front of the gloss so that "\exg. *Das ist ..." hangs the star left
%% of the first column:
\def\lx@glosshead{\lx@scanjudgeto{\lx@emitjudge\gll}}

\def\lx@subpush{%
  \ifcase\lx@subdepth
    \let\lx@donext\lx@subpush@i
  \or
    \let\lx@donext\lx@subpush@ii
  \else
    \let\lx@donext\lx@subpush@err
  \fi
  \lx@donext}

% the two sub-level list declarations, shared by the dot-command path
% (\a.) and the environment path (xlist)
\def\lx@sublist@i{%
  \setcounter{SubExNo}{0}%
  \lx@openlist{\lx@geom@sub
     \itemindent\z@ \listparindent\z@ \parsep\z@ \itemsep\z@
     \partopsep\z@ \parskip\z@
     \let\makelabel\lx@flushlabel}}
\def\lx@sublist@ii{%
  \setcounter{SubSubExNo}{0}%
  \lx@openlist{\lx@geom@subsub
     \itemindent\z@ \listparindent\z@ \parsep\z@ \itemsep\z@
     \partopsep\z@ \parskip\z@
     \let\makelabel\lx@flushlabel}}

% depth 0 -> open letter level
\def\lx@subpush@i{%
  \begingroup\advance\lx@subdepth\@ne
  \lx@sublist@i
  \lx@subitem}

% depth 1 -> open roman level
\def\lx@subpush@ii{%
  \begingroup\advance\lx@subdepth\@ne
  \lx@sublist@ii
  \lx@subsubitem}

\def\lx@subpush@err{%
  \PackageError{linguexx}{Only two sub-example levels are supported}%
    {Remove the third \string\a. level.}}

\def\lx@subnext{%
  \ifcase\lx@subdepth
    \let\lx@donext\lx@subnext@err
  \or
    \let\lx@donext\lx@subitem
  \or
    \let\lx@donext\lx@subsubitem
  \fi
  \lx@donext}

\def\lx@subnext@err{%
  \PackageError{linguexx}{\string\b. (or \string\c. etc.) without a
    preceding \string\a.}{Start the sublevel with \string\a. first.}}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%  Environment interface: exe and xlist (gb4e-compatible)             %%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% begin code for the sub-level environment: the environment's own group
% plays the role of the \begingroup in \lx@subpush, so the depth
% advance is undone at the matching \end
\def\lx@subenv@begin{%
   \advance\lx@subdepth\@ne
   \ifcase\lx@subdepth
     \let\lx@donext\relax % unreachable
   \or
     \let\lx@donext\lx@sublist@i
   \or
     \let\lx@donext\lx@sublist@ii
   \else
     \let\lx@donext\lx@subpush@err
   \fi
   \lx@donext
   \def\item{\lx@subnext}}

%% exe is a BATCH: each \ex inside it is a new top-level example;
%% xlist embeds a sub-level (letters, then romans), with \ex as the
%% item command (plain \item works too).  Judgments are given
%% gb4e-style as \ex[*]{text} -- the optional argument may be ANY mark,
%% not only the auto-detected set -- or typed directly after a plain
%% \ex, as everywhere else in this package.  Both environments drive
%% the same engine as \ex./\a., so the two syntaxes share one counter
%% and may be mixed freely, even within one example (an xlist inside a
%% dot-command \a., or \a. inside exe).
\iflx@gbfour
\NewDocumentEnvironment{exe}{}
  {\ifdim\lastskip=\Extopsep\vspace{\Exredux}\fi
   \lx@subdepth\z@
   \setcounter{SubExNo}{0}\setcounter{SubSubExNo}{0}%
   \lx@inexetrue
   \lx@guesslabel
   \lx@mainlist
   % consecutive examples in a batch get the same vertical rhythm as
   % consecutive \ex. examples (net \Extopsep between them)
   \itemsep\Extopsep}
  {\lx@closelist}

\NewDocumentEnvironment{xlist}{}
  {\lx@subenv@begin
   \lx@inexetrue}
  {\lx@closelist}
\fi % iflx@gbfour

\def\lx@subitem@core{%
  \refstepcounter{SubExNo}%
  \def\lx@itemlabel{\SubExLBr\Exalph{SubExNo}\SubExRBr}}
\def\lx@subitem{\lx@subitem@core\lx@scanjudge}
\def\lx@subsubitem@core{%
  \refstepcounter{SubSubExNo}%
  \def\lx@itemlabel{\SubSubExLBr\Exroman{SubSubExNo}\SubSubExRBr}}
\def\lx@subsubitem{\lx@subsubitem@core\lx@scanjudge}

% close all sublists still open at the end of the example body;
% every \endgroup restores \lx@subdepth to its value one level up,
% so this terminates by construction
\def\lx@closesubs{%
  \ifnum\lx@subdepth>\z@
    \lx@closelist\endgroup
    \expandafter\lx@closesubs
  \fi}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%  Relative references: \Next \Last \NNext \LLast \TextNext           %%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\newcommand\lx@fmtEx[1]{\theExLBr#1\theExRBr}
\newcommand\lx@fmtFnEx[1]{\theFnExLBr#1\theFnExRBr}

\newcommand\Last{{\if@noftnote
    \lx@fmtEx{\arabic{ExNo}}%
  \else\ifnum\value{FnExNo}>\z@
    \lx@fmtFnEx{\roman{FnExNo}}%
  \else
    \lx@fmtEx{\arabic{ExNo}}%
  \fi\fi}}

\newcommand\Next{{\if@noftnote
    \lx@fmtEx{\the\numexpr\value{ExNo}+1\relax}%
  \else
    \lx@fmtFnEx{\romannumeral\numexpr\value{FnExNo}+1\relax}%
  \fi}}

\newcommand\NNext{{\if@noftnote
    \lx@fmtEx{\the\numexpr\value{ExNo}+2\relax}%
  \else
    \lx@fmtFnEx{\romannumeral\numexpr\value{FnExNo}+2\relax}%
  \fi}}

\newcommand\LLast{{\if@noftnote
    \lx@fmtEx{\the\numexpr\value{ExNo}-1\relax}%
  \else\ifnum\value{FnExNo}>\@ne
    \lx@fmtFnEx{\romannumeral\numexpr\value{FnExNo}-1\relax}%
  \else
    \lx@fmtEx{\arabic{ExNo}}%
  \fi\fi}}

\newcommand\TextNext{{\lx@fmtEx{\the\numexpr\value{ExNo}+1\relax}}}

% parenthesis-free twins
\newcommand\pref[1]{{\parenstrue\ref{#1}}}
\newcommand\pLast{{\parenstrue\Last}}
\newcommand\pNext{{\parenstrue\Next}}
\newcommand\pNNext{{\parenstrue\NNext}}
\newcommand\pLLast{{\parenstrue\LLast}}
\newcommand\pTextNext{{\parenstrue\TextNext}}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%  Interlinear glossing: \gll \glll \glt (cgloss4e replacement)       %%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%% \gll  object line \\ gloss line \\
%% \glll object line \\ gloss line \\ second gloss line \\
%% \glt  free translation (typeset on a new line)
%%
%% Words are separated by spaces; {braced material} counts as one word
%% (so {ein Beispiel} shares a single gloss).  If lines have unequal
%% length, missing cells are empty.  Column pairs are set as \vtop boxes
%% flowing in a ragged-right paragraph, so long examples wrap between
%% columns.  Fonts per line: \eachwordone/\eachwordtwo/\eachwordthree
%% (default \textnormal, so beamer's sans-serif is respected without
%% any patching).  Inter-column glue: \GlossSep (a macro holding a glue
%% specification).

\let\eachwordone\textnormal
\let\eachwordtwo\textnormal
\let\eachwordthree\textnormal
% \GlossSep (the glue between gloss columns) is a macro, not a length, and
% its value is set in the defaults block of the Layout section above.

%% Per-tier fonts: tier n is set with the one-argument command declared
%% by \GlossTierFont{n}{cmd}.  Tiers 1--3 are pre-declared to dispatch
%% through \eachwordone/\eachwordtwo/\eachwordthree, so redefining those
%% still works (and beamer's sans-serif is respected as before);
%% undeclared tiers fall back to \textnormal.
\newcommand\GlossTierFont[2]{%
  \expandafter\def\csname lx@glfont@#1\endcsname{#2}}
\expandafter\def\csname lx@glfont@1\endcsname{\eachwordone}
\expandafter\def\csname lx@glfont@2\endcsname{\eachwordtwo}
\expandafter\def\csname lx@glfont@3\endcsname{\eachwordthree}

\ExplSyntaxOn
\tl_new:N  \l__lx_gl_tmp_tl
\seq_new:N \l__lx_gl_lines_seq
\int_new:N \l__lx_gl_ntiers_int
\int_new:N \l__lx_gl_maxwords_int
\quark_new:N \q__lx_sep
\cs_generate_variant:Nn \seq_set_split:Nnn { NnV }

% split #2 on space tokens into seq #1, dropping empty items
\cs_new_protected:Npn \__lx_split:Nn #1#2
  {
    \tl_set:Nn \l__lx_gl_tmp_tl {#2}
    \tl_replace_all:Nnn \l__lx_gl_tmp_tl { ~ } { \q__lx_sep }
    \seq_set_split:NnV #1 { \q__lx_sep } \l__lx_gl_tmp_tl
    \seq_remove_all:Nn #1 { }
  }
\cs_generate_variant:Nn \__lx_split:Nn { cn }

% tier font application: \lx@glfontuse{tier}{word}
\cs_new_protected:Npn \lx@glfontuse #1#2
  {
    \cs_if_exist_use:cF { lx@glfont@ #1 }
      { \textnormal }
    {#2}
  }

%% Objective 4: interlinear glosses as structure.  Visually a gloss is a
%% grid; for a screen reader what matters is that the object word and its
%% gloss(es) are read together and are navigable as a unit.  The content
%% is emitted column by column (word 1 of every tier, then word 2, ...),
%% so the reading order is already word-by-word; here we additionally
%% wrap each column in a Span so the aligned bundle is one structure
%% element rather than loose text in a paragraph.  Tag-guarded: no effect
%% without active tagging, and the printed grid is unchanged.
\ExplSyntaxOn
%% Objective 5: language of a gloss tier.  \GlossTierLang{tier}{lang}
%% records a (BCP-47) language code for a tier; under tagging each word
%% of that tier is wrapped in a Span carrying /Lang, so a screen reader
%% pronounces the object language with its own phonetics instead of the
%% document's.  Tiers with no declared language behave exactly as before.
%% Scoping: \GlossTierLang uses a LOCAL assignment on a local property.
%% Issued in the preamble or document body it sets the document-wide
%% default (it persists to the end of its enclosing group); issued inside
%% an example -- whose body is typeset within the example's list group --
%% it overrides only that example and reverts afterwards.
\prop_new:N \l_lx_gl_lang_prop
\tl_new:N  \l__lx_gl_lang_tl
\NewDocumentCommand \GlossTierLang { m m }
  { \prop_put:Nnn \l_lx_gl_lang_prop {#1} {#2} }
\cs_generate_variant:Nn \tag_struct_begin:n { e }

%% Objective 6: Leipzig glossing abbreviations with spoken expansions.
%% \lpzg{sg} typesets the abbreviation in small caps and, under tagging,
%% wraps it in a Span carrying /E (the PDF "expansion text" of an
%% abbreviation), so a screen reader announces "singular" while the page
%% still shows SG and copy-and-paste still yields SG.  The table below is
%% the standard Leipzig Glossing Rules list, keyed by the printed short
%% form (lower case); extend or override an entry with
%% \SetLeipzig{key}{expansion}.  An unknown key is printed in small caps
%% with no expansion (no warning).  Nothing happens without active
%% tagging; the printed output is unaffected either way.
\prop_new:N \g_lx_lpzg_prop
\tl_new:N  \l__lx_lpzg_tl
\prop_gset_from_keyval:Nn \g_lx_lpzg_prop
  {
    1 = first~person ,
    2 = second~person ,
    3 = third~person ,
    a = agent ,
    abl = ablative ,
    abs = absolutive ,
    acc = accusative ,
    adj = adjective ,
    adv = adverbial ,
    agr = agreement ,
    all = allative ,
    antip = antipassive ,
    appl = applicative ,
    art = article ,
    aux = auxiliary ,
    ben = benefactive ,
    caus = causative ,
    clf = classifier ,
    com = comitative ,
    comp = complementizer ,
    compl = completive ,
    cond = conditional ,
    cop = copula ,
    cvb = converb ,
    dat = dative ,
    decl = declarative ,
    def = definite ,
    dem = demonstrative ,
    det = determiner ,
    dist = distal ,
    distr = distributive ,
    du = dual ,
    dur = durative ,
    erg = ergative ,
    excl = exclusive ,
    f = feminine ,
    foc = focus ,
    fut = future ,
    gen = genitive ,
    imp = imperative ,
    incl = inclusive ,
    ind = indicative ,
    indf = indefinite ,
    inf = infinitive ,
    ins = instrumental ,
    intr = intransitive ,
    ipfv = imperfective ,
    irr = irrealis ,
    loc = locative ,
    m = masculine ,
    n = neuter ,
    neg = negative ,
    nmlz = nominalizer ,
    nom = nominative ,
    obj = object ,
    obl = oblique ,
    p = patient ,
    pass = passive ,
    pfv = perfective ,
    pl = plural ,
    poss = possessive ,
    pred = predicative ,
    prf = perfect ,
    prog = progressive ,
    proh = prohibitive ,
    prox = proximal ,
    prs = present ,
    pst = past ,
    ptcp = participle ,
    purp = purposive ,
    q = question~particle ,
    quot = quotative ,
    recp = reciprocal ,
    refl = reflexive ,
    rel = relative ,
    res = resultative ,
    s = argument~of~intransitive~verb ,
    sbj = subject ,
    sbjv = subjunctive ,
    sg = singular ,
    top = topic ,
    tr = transitive ,
    voc = vocative ,
  }
\NewDocumentCommand \SetLeipzig { m m }
  { \prop_gput:Nnn \g_lx_lpzg_prop {#1} {#2} }
%% \lpzg accepts a compound gloss label as a single argument, following the
%% Leipzig convention: a leading person digit is written flush against the
%% number (3sg), and further categories are separated by a period
%% (3sg.nom).  The whole label is typeset once in small caps; for the
%% spoken expansion (/E) it is parsed into pieces -- each period-separated
%% segment, with any leading 1/2/3 peeled off as a person -- and each
%% piece is expanded from the table.  Pieces not in the table pass through
%% verbatim; if nothing at all expands, no /E is emitted (the small caps
%% stand alone, exactly as for a truly unknown label).
\tl_new:N   \l__lx_lpzg_exp_tl
\str_new:N  \l__lx_lpzg_rest_str
\bool_new:N \l__lx_lpzg_any_bool
\seq_new:N  \l__lx_lpzg_seg_seq
\cs_new_protected:Npn \lx@lpzg@append #1
  {
    \tl_if_empty:NTF \l__lx_lpzg_exp_tl
      { \tl_set:Nn  \l__lx_lpzg_exp_tl {#1} }
      { \tl_put_right:Nn \l__lx_lpzg_exp_tl { ~ #1 } }
  }
\cs_new_protected:Npn \lx@lpzg@lookup #1
  {
    \lx@lpzg@record {#1}
    \prop_get:NnNTF \g_lx_lpzg_prop {#1} \l__lx_lpzg_tl
      { \bool_set_true:N \l__lx_lpzg_any_bool
        \exp_args:NV \lx@lpzg@append \l__lx_lpzg_tl }
      { \lx@lpzg@append {#1} }
  }
\cs_new_protected:Npn \lx@lpzg@seg #1
  {
    \str_set:Ne \l__lx_lpzg_rest_str { \str_head:n {#1} }
    \bool_lazy_any:nTF
      {
        { \str_if_eq_p:Vn \l__lx_lpzg_rest_str { 1 } }
        { \str_if_eq_p:Vn \l__lx_lpzg_rest_str { 2 } }
        { \str_if_eq_p:Vn \l__lx_lpzg_rest_str { 3 } }
      }
      {
        \exp_args:Ne \lx@lpzg@lookup { \str_head:n {#1} }
        \str_set:Ne \l__lx_lpzg_rest_str { \str_tail:n {#1} }
        \str_if_empty:NF \l__lx_lpzg_rest_str
          { \exp_args:NV \lx@lpzg@lookup \l__lx_lpzg_rest_str }
      }
      { \lx@lpzg@lookup {#1} }
  }
\cs_new_protected:Npn \lx@lpzg@build #1
  {
    \tl_clear:N \l__lx_lpzg_exp_tl
    \bool_set_false:N \l__lx_lpzg_any_bool
    \seq_set_split:Nnn \l__lx_lpzg_seg_seq { . } {#1}
    \seq_map_inline:Nn \l__lx_lpzg_seg_seq { \lx@lpzg@seg {##1} }
  }
\NewDocumentCommand \lpzg { m }
  {
    \lx@lpzg@build {#1}
    \bool_lazy_and:nnTF
      { \cs_if_exist_p:N \tag_struct_begin:n }
      { \l__lx_lpzg_any_bool }
      {
        \tag_if_active:TF
          {
            \tag_mc_end_push:
            \tag_struct_begin:e { tag = Span , E = { \l__lx_lpzg_exp_tl } }
            \tag_mc_begin:n { tag = Span }
            \textsc {#1}
            \tag_mc_end:
            \tag_struct_end:
            \tag_mc_begin_pop:n {}
          }
          { \textsc {#1} }
      }
      { \textsc {#1} }
  }

%% \lpzglist: the list of abbreviations the document actually uses.
%%
%% Every piece \lpzg resolves is recorded -- the ATOMIC pieces, so
%% \lpzg{3sg.pst} contributes 3, sg and pst separately, which is what a
%% list of abbreviations wants.  Each key is recorded once and written to
%% the .aux, so \lpzglist may stand anywhere, in particular in the front
%% matter, before the uses it reports on: it prints the keys of the
%% PREVIOUS run plus everything used so far in this one (so a list at the
%% end of the document is already complete on the first run).  A key that
%% the .aux did not know about, or that no list accounts for, means some
%% list came out short: \AtEndDocument asks for a rerun, as for a table of
%% contents.
%%
%% Keys with no known expansion (project labels not in the Leipzig table
%% and not declared with \SetLeipzig) are omitted and reported once; ask
%% for unexplained=keep to list them with an empty explanation instead.
%%
%% Every key is normalised to a STRING before it is stored or compared.
%% It has to be: a label reaches \lpzg as letters, but the piece peeled
%% off a compound one comes out of a str variable (catcode 12), and the
%% keys read back from the .aux are letters again -- three spellings of
%% "sg" that a seq would take for three different entries.
\seq_new:N  \g__lx_lpzg_used_seq   % keys seen on THIS run, in order of use
\prop_new:N \g__lx_lpzg_used_prop  % the same, as a set: the duplicate guard
\seq_new:N  \g__lx_lpzg_aux_seq    % keys read back from the .aux (last run)
\bool_new:N \g__lx_lpzg_doc_bool   % true once the .aux is open for writing
\bool_new:N \g__lx_lpzg_rerun_bool % a key the .aux did not know about
\str_new:N  \l__lx_lpzg_key_str
\AtBeginDocument { \bool_gset_true:N \g__lx_lpzg_doc_bool }
%% written to and read from the .aux
\cs_new_protected:Npn \lx@lpzg@used #1
  { \seq_gput_right:Ne \g__lx_lpzg_aux_seq { \tl_to_str:n {#1} } }
\bool_new:N \l__lx_lpzg_norecord_bool % true while \lpzglist typesets itself
\cs_new_protected:Npn \lx@lpzg@record #1
  {
    \bool_if:NF \l__lx_lpzg_norecord_bool
      { \lx@lpzg@record@ {#1} }
  }
\cs_new_protected:Npn \lx@lpzg@record@ #1
  {
    \str_set:Nn \l__lx_lpzg_key_str {#1}
    \prop_if_in:NVF \g__lx_lpzg_used_prop \l__lx_lpzg_key_str
      {
        \prop_gput:NVn \g__lx_lpzg_used_prop \l__lx_lpzg_key_str { }
        \seq_gput_right:NV \g__lx_lpzg_used_seq \l__lx_lpzg_key_str
        %% Recorded in the preamble, a key is there before any list is
        %% typeset, so it needs neither the .aux nor a rerun.  Recorded in
        %% the body and unknown to the .aux, it means the .aux is one run
        %% behind and a list placed before this point is short of an entry.
        \bool_if:NT \g__lx_lpzg_doc_bool
          {
            \seq_if_in:NVF \g__lx_lpzg_aux_seq \l__lx_lpzg_key_str
              { \bool_gset_true:N \g__lx_lpzg_rerun_bool }
            \legacy_if:nT { @filesw }
              { \iow_now:Ne \@auxout
                  { \token_to_str:N \lx@lpzg@used { \l__lx_lpzg_key_str } } }
          }
      }
  }
%% \lpzgadd{key,key,...} records abbreviations used outside \lpzg (in a
%% figure, in running text) so that they appear in the list all the same.
\NewDocumentCommand \lpzgadd { m }
  { \clist_map_inline:nn {#1} { \lx@lpzg@record@ {##1} } }

\seq_new:N   \l__lx_lpzglist_seq        % the entries to print
\seq_new:N   \l__lx_lpzglist_tmp_seq
\seq_new:N   \l__lx_lpzglist_unknown_seq
\seq_new:N   \g__lx_lpzglist_printed_seq
\bool_new:N  \g__lx_lpzglist_used_bool
\bool_new:N  \l__lx_lpzglist_rerun_bool
\bool_new:N  \l__lx_lpzglist_first_bool
\box_new:N   \l__lx_lpzglist_box
\dim_new:N   \l__lx_lpzglist_wd_dim
\msg_new:nnn { linguexx } { lpzglist-rerun }
  {
    Abbreviation~list~out~of~date.~
    Rerun~LaTeX~to~get~\iow_char:N \\lpzglist~right.
  }
\msg_new:nnn { linguexx } { lpzglist-unknown }
  {
    No~expansion~known~for~#1~--~omitted~from~
    \iow_char:N \\lpzglist.\\
    Declare~it~with~\iow_char:N \\SetLeipzig,~
    or~pass~unexplained=keep~to~list~it~unexplained.
  }

%% Presentation.  Everything below is either a key of \lpzglist (set for
%% one list) or of \lpzglistsetup (set for all of them), or one of the two
%% user commands \lpzglistentry / \lpzglisttitle, which may be redefined
%% wholesale with \renewcommand.
\str_new:N   \l__lx_lpzglist_style_str
\str_new:N   \l__lx_lpzglist_incl_str
\tl_new:N    \l__lx_lpzglist_title_tl
\tl_new:N    \l__lx_lpzglist_titlestyle_tl
\tl_new:N    \l__lx_lpzglist_sep_tl
\clist_new:N \l__lx_lpzglist_ignore_clist
\clist_new:N \l__lx_lpzglist_add_clist
\bool_new:N  \l__lx_lpzglist_sort_bool
\bool_new:N  \l__lx_lpzglist_keepun_bool
\skip_new:N  \l__lx_lpzglist_itemsep_skip
\keys_define:nn { lx / lpzglist }
  {
    style        .choices:nn =
      { list , inline }
      { \str_set:NV \l__lx_lpzglist_style_str \l_keys_choice_tl } ,
    include      .choices:nn =
      { used , all }
      { \str_set:NV \l__lx_lpzglist_incl_str \l_keys_choice_tl } ,
    sort         .bool_set:N  = \l__lx_lpzglist_sort_bool ,
    sort         .default:n   = { true } ,
    unexplained  .choices:nn  =
      { omit , keep }
      {
        \bool_set:Nn \l__lx_lpzglist_keepun_bool
          { \str_if_eq_p:Vn \l_keys_choice_tl { keep } }
      } ,
    unexplained  .default:n   = { keep } ,
    title        .tl_set:N    = \l__lx_lpzglist_title_tl ,
    titlestyle   .tl_set:N    = \l__lx_lpzglist_titlestyle_tl ,
    sep          .tl_set:N    = \l__lx_lpzglist_sep_tl ,
    itemsep      .skip_set:N  = \l__lx_lpzglist_itemsep_skip ,
    ignore       .clist_set:N = \l__lx_lpzglist_ignore_clist ,
    add          .clist_set:N = \l__lx_lpzglist_add_clist ,
    format       .code:n      =
      { \cs_set_protected:Npn \lpzglistentry ##1##2 {#1} } ,
  }
\keys_set:nn { lx / lpzglist }
  {
    style = list , include = used , sort = true , unexplained = omit ,
    title = { } , titlestyle = \lpzglisttitle , sep = { ;~ } ,
    itemsep = 0pt ,
  }
\NewDocumentCommand \lpzglistsetup { m }
  { \keys_set:nn { lx / lpzglist } {#1} }
%% One entry: #1 the key, #2 its expansion (empty if none is known).
\NewDocumentCommand \lpzglistentry { m m }
  {
    \str_if_eq:VnTF \l__lx_lpzglist_style_str { inline }
      { \lpzg {#1} ~ #2 }
      { \item [ \lpzg {#1} ] #2 }
  }
\NewDocumentCommand \lpzglisttitle { m }
  {
    \cs_if_exist:NTF \section
      { \section * {#1} }
      { \par \noindent \textbf {#1} \par \nobreak \smallskip }
  }

%% Collect the keys to print, in printing order.  Keys arrive as strings
%% from the recorder, but as letters from the built-in table and from the
%% add= and ignore= lists, so every one of them is normalised here too.
\cs_generate_variant:Nn \seq_remove_all:Nn { NV }
\cs_new_protected:Npn \lx@lpzglist@put #1
  {
    \str_set:Nn \l__lx_lpzg_key_str {#1}
    \seq_if_in:NVF \l__lx_lpzglist_seq \l__lx_lpzg_key_str
      { \seq_put_right:NV \l__lx_lpzglist_seq \l__lx_lpzg_key_str }
  }
\cs_new_protected:Npn \lx@lpzglist@collect
  {
    \seq_clear:N \l__lx_lpzglist_seq
    \seq_clear:N \l__lx_lpzglist_unknown_seq
    \str_if_eq:VnTF \l__lx_lpzglist_incl_str { all }
      { \prop_map_inline:Nn \g_lx_lpzg_prop { \lx@lpzglist@put {##1} } }
      {
        %% the .aux (a full run) first, this run's new keys after it, so
        %% that sort=false yields the order of first use
        \seq_map_inline:Nn \g__lx_lpzg_aux_seq  { \lx@lpzglist@put {##1} }
        \seq_map_inline:Nn \g__lx_lpzg_used_seq { \lx@lpzglist@put {##1} }
      }
    \clist_map_inline:Nn \l__lx_lpzglist_add_clist { \lx@lpzglist@put {##1} }
    \clist_map_inline:Nn \l__lx_lpzglist_ignore_clist
      {
        \str_set:Nn \l__lx_lpzg_key_str {##1}
        \seq_remove_all:NV \l__lx_lpzglist_seq \l__lx_lpzg_key_str
      }
    \seq_set_eq:NN \l__lx_lpzglist_tmp_seq \l__lx_lpzglist_seq
    \seq_clear:N \l__lx_lpzglist_seq
    \seq_map_inline:Nn \l__lx_lpzglist_tmp_seq
      {
        \prop_if_in:NnTF \g_lx_lpzg_prop {##1}
          { \seq_put_right:Nn \l__lx_lpzglist_seq {##1} }
          {
            \seq_put_right:Nn \l__lx_lpzglist_unknown_seq {##1}
            \bool_if:NT \l__lx_lpzglist_keepun_bool
              { \seq_put_right:Nn \l__lx_lpzglist_seq {##1} }
          }
      }
    \bool_if:NT \l__lx_lpzglist_sort_bool
      {
        \seq_sort:Nn \l__lx_lpzglist_seq
          {
            \str_compare:nNnTF {##1} > {##2}
              { \sort_return_swapped: } { \sort_return_same: }
          }
      }
  }
%% One entry, expansion looked up (empty for an unknown key kept on request).
\cs_new_protected:Npn \lx@lpzglist@item #1
  {
    \prop_get:NnNTF \g_lx_lpzg_prop {#1} \l__lx_lpzg_tl
      { \exp_args:NnV \lpzglistentry {#1} \l__lx_lpzg_tl }
      { \lpzglistentry {#1} { } }
  }
%% The label column is as wide as the widest abbreviation.  Measured with
%% \textsc, which is what \lpzg prints, and NOT with \lpzg itself: \lpzg
%% opens structure elements, and a box that is measured and thrown away
%% would leave them behind in the tree.
\cs_new_protected:Npn \lx@lpzglist@widest
  {
    \dim_zero:N \l__lx_lpzglist_wd_dim
    \seq_map_inline:Nn \l__lx_lpzglist_seq
      {
        \hbox_set:Nn \l__lx_lpzglist_box { \textsc {##1} }
        \dim_set:Nn \l__lx_lpzglist_wd_dim
          { \dim_max:nn \l__lx_lpzglist_wd_dim { \box_wd:N \l__lx_lpzglist_box } }
      }
  }
\cs_new_protected:Npn \lx@lpzglist@dolist
  {
    \lx@lpzglist@widest
    %% No \lx@ol@set here: the abbreviation list is NOT an ordered list,
    %% and it keeps the block code's own class for a labelled list.  A
    %% class of its own carrying /ListNumbering /None looks right and is
    %% not: PDF/UA-2 8.2.5.25 forbids /None precisely when the items have
    %% Lbl elements, which these do (veraPDF rejects the file).  What the
    %% block code puts there instead is /Unordered, which is what a
    %% labelled list is; poppler warns about the value, veraPDF accepts it.
    \begin { list } { }
      {
        \dim_set:Nn \labelwidth { \l__lx_lpzglist_wd_dim }
        \dim_set:Nn \leftmargin { \labelwidth + \labelsep }
        \dim_zero:N \itemindent
        \dim_zero:N \listparindent
        \dim_zero:N \rightmargin
        \skip_set_eq:NN \itemsep \l__lx_lpzglist_itemsep_skip
        \skip_zero:N \parsep
        \skip_zero:N \partopsep
        %% \lx@flushlabel, not \hfil: under active tagging the block code
        %% re-boxes a label flush RIGHT unless it already fills its own
        %% \labelwidth box (the same reason the example labels use it).
        \cs_set_eq:NN \makelabel \lx@flushlabel
      }
      \seq_map_inline:Nn \l__lx_lpzglist_seq { \lx@lpzglist@item {##1} }
    \end { list }
  }
%% The \unskip guards the separator against an entry whose expansion is
%% empty (an unexplained key kept on request), which would otherwise leave
%% the space of the entry format sitting in front of the semicolon.
\cs_new_protected:Npn \lx@lpzglist@doinline
  {
    \bool_set_true:N \l__lx_lpzglist_first_bool
    \seq_map_inline:Nn \l__lx_lpzglist_seq
      {
        \bool_if:NTF \l__lx_lpzglist_first_bool
          { \bool_set_false:N \l__lx_lpzglist_first_bool }
          { \unskip \l__lx_lpzglist_sep_tl }
        \lx@lpzglist@item {##1}
      }
    \unskip
  }
\cs_new_protected:Npn \lx@lpzglist@render
  {
    \tl_if_blank:VF \l__lx_lpzglist_title_tl
      { \l__lx_lpzglist_titlestyle_tl { \l__lx_lpzglist_title_tl } }
    \str_if_eq:VnTF \l__lx_lpzglist_style_str { inline }
      { \lx@lpzglist@doinline }
      { \lx@lpzglist@dolist }
  }
\NewDocumentCommand \lpzglist { O{} }
  {
    \group_begin:
      %% the list's own \lpzg calls must not enlarge the set they report on
      \bool_set_true:N \l__lx_lpzg_norecord_bool
      \keys_set:nn { lx / lpzglist } {#1}
      \lx@lpzglist@collect
      \bool_gset_true:N \g__lx_lpzglist_used_bool
      %% what this list accounts for: everything it prints, everything it
      %% was told to leave out, and the keys it could not explain (those
      %% are reported here and now, not as a rerun request)
      \seq_map_inline:Nn \l__lx_lpzglist_seq
        { \seq_gput_right:Nn \g__lx_lpzglist_printed_seq {##1} }
      \seq_map_inline:Nn \l__lx_lpzglist_unknown_seq
        { \seq_gput_right:Nn \g__lx_lpzglist_printed_seq {##1} }
      \clist_map_inline:Nn \l__lx_lpzglist_ignore_clist
        { \seq_gput_right:Ne \g__lx_lpzglist_printed_seq { \tl_to_str:n {##1} } }
      \seq_if_empty:NF \l__lx_lpzglist_seq { \lx@lpzglist@render }
      \bool_lazy_and:nnT
        { ! \l__lx_lpzglist_keepun_bool }
        { ! \seq_if_empty_p:N \l__lx_lpzglist_unknown_seq }
        {
          \msg_warning:nnx { linguexx } { lpzglist-unknown }
            { \seq_use:Nnnn \l__lx_lpzglist_unknown_seq { ~and~ } { ,~ } { ,~and~ } }
        }
    \group_end:
  }
%% Anything used but not accounted for by a list means the .aux was one
%% run behind: ask for a rerun, as \tableofcontents does.
\cs_new_protected:Npn \lx@lpzglist@checkrerun
  {
    \bool_if:NT \g__lx_lpzglist_used_bool
      {
        \bool_set_eq:NN \l__lx_lpzglist_rerun_bool \g__lx_lpzg_rerun_bool
        \seq_map_inline:Nn \g__lx_lpzg_used_seq
          {
            \seq_if_in:NnF \g__lx_lpzglist_printed_seq {##1}
              { \bool_set_true:N \l__lx_lpzglist_rerun_bool }
          }
        \bool_if:NT \l__lx_lpzglist_rerun_bool
          { \msg_warning:nn { linguexx } { lpzglist-rerun } }
      }
  }
\AtEndDocument { \lx@lpzglist@checkrerun }

\cs_new_protected:Npn \lx@gl@colbegin
  { \cs_if_exist:NT \tag_struct_begin:n
      { \tag_if_active:T
          { \tag_mc_end_push: \tag_struct_begin:n { tag = Span } } } }
\cs_new_protected:Npn \lx@gl@colend
  { \cs_if_exist:NT \tag_struct_end:
      { \tag_if_active:T
          { \tag_struct_end: \tag_mc_begin_pop:n {} } } }
%% #1 = tier number.  If the tier has a declared language, wrap the word
%% in its own Span with /Lang (nested in the column Span); otherwise emit
%% plain marked content as before.
\cs_new_protected:Npn \lx@gl@wordbegin #1
  { \cs_if_exist:NT \tag_mc_begin:n
      { \tag_if_active:T
          {
            \prop_get:NnNTF \l_lx_gl_lang_prop {#1} \l__lx_gl_lang_tl
              { \tag_struct_begin:e { tag = Span , lang = \l__lx_gl_lang_tl } }
              { }
            \tag_mc_begin:n { tag = Span }
          } } }
\cs_new_protected:Npn \lx@gl@wordend #1
  { \cs_if_exist:NT \tag_mc_end:
      { \tag_if_active:T
          {
            \tag_mc_end:
            \prop_if_in:NnT \l_lx_gl_lang_prop {#1} { \tag_struct_end: }
          } } }
\ExplSyntaxOff
\ExplSyntaxOn
%% Phantom bracket alignment (opt-in, off by default).  When a word in the
%% object line opens with a run of delimiter/judgment characters -- e.g.
%% "[ein" in "ich bin [ein Idiot]" -- the gloss word below it normally
%% left-aligns with the "[", not with "ein".  With alignment on, the gloss
%% word (and any further tiers) is preceded by a \phantom of that leading
%% run, SET IN THE OBJECT-TIER FONT, so its first real glyph sits under the
%% first real glyph of the object word regardless of the gloss-tier size
%% (e.g. \footnotesize glosses still line up).  The phantom ships no ink and
%% no marked content, so tagging is unaffected.  Enable with the package
%% option [phantomalign] or \GlossPhantomAlign; \GlossPhantomAlignOff turns
%% it back off.  \GlossPhantomChars sets the leading characters that count
%% (default: the judgment marks * ? # % and the openers ( [ < ).  \altg
%% alternative columns are not covered.
\bool_new:N \l__lx_gl_phantom_bool
\iflx@phantomalign \bool_set_true:N \l__lx_gl_phantom_bool \fi
\str_new:N \l__lx_gl_phantomchars_str
% The set must hold BARE "#" and "%": writing them as \#\% in \str_set:Nn
% would stringify to "\#\%" and leave literal backslashes in the set, so any
% object word beginning with a control sequence would then match "\" and be
% padded.  \c_hash_str / \c_percent_str are the catcode-12 characters.
\str_set:Ne \l__lx_gl_phantomchars_str { *?([< \c_hash_str \c_percent_str }
\tl_new:N  \l__lx_gl_prefix_tl
\tl_new:N  \l__lx_gl_obj_tl
\str_new:N \l__lx_gl_word_str
\str_new:N \l__lx_gl_head_str
\prg_generate_conditional_variant:Nnn \str_if_in:Nn { NV } { T }
\cs_new_protected:Npn \GlossPhantomAlign
  { \bool_set_true:N \l__lx_gl_phantom_bool }
\cs_new_protected:Npn \GlossPhantomAlignOff
  { \bool_set_false:N \l__lx_gl_phantom_bool }
\cs_new_protected:Npn \GlossPhantomChars #1
  { \str_set:Nn \l__lx_gl_phantomchars_str {#1} }
% Manual per-word override: \GlossPhantom{stuff} typesets an invisible box
% the width of #1 SET IN THE OBJECT-TIER FONT.  Placed at the front of a
% gloss word it aligns that word past #1 regardless of the automatic
% detection or the gloss-tier size -- for material the auto-scanner cannot
% see (a macro-wrapped bracket, a whole prefix word) or a bespoke target.
\cs_new_protected:Npn \GlossPhantom #1
  { \phantom { \lx@glfontuse {1} {#1} } }
% Peel the leading run of phantom characters off word #1 into
% \l__lx_gl_prefix_tl (as a str; catcode-12 punctuation, safe in \phantom).
\cs_new_protected:Npn \__lx_gl_leadprefix:N #1
  {
    \tl_clear:N \l__lx_gl_prefix_tl
    \str_set:Nx \l__lx_gl_word_str { \tl_to_str:N #1 }
    \__lx_gl_leadprefix_loop:
  }
\cs_new_protected:Npn \__lx_gl_leadprefix_loop:
  {
    \str_if_empty:NF \l__lx_gl_word_str
      {
        \str_set:Nx \l__lx_gl_head_str { \str_head:N \l__lx_gl_word_str }
        \str_if_in:NVT \l__lx_gl_phantomchars_str \l__lx_gl_head_str
          {
            \tl_put_right:NV \l__lx_gl_prefix_tl \l__lx_gl_head_str
            \str_set:Nx \l__lx_gl_word_str { \str_tail:N \l__lx_gl_word_str }
            \__lx_gl_leadprefix_loop:
          }
      }
  }
\cs_gset_protected:Npn \lx@gloss@multi #1
  {
    \seq_set_split:Nnn \l__lx_gl_lines_seq { \\ } {#1}
    \seq_remove_all:Nn \l__lx_gl_lines_seq { }
    \int_zero:N \l__lx_gl_ntiers_int
    \int_zero:N \l__lx_gl_maxwords_int
    \seq_map_inline:Nn \l__lx_gl_lines_seq
      {
        \int_incr:N \l__lx_gl_ntiers_int
        \seq_clear_new:c
          { l__lx_gl_tier_ \int_use:N \l__lx_gl_ntiers_int _seq }
        \__lx_split:cn
          { l__lx_gl_tier_ \int_use:N \l__lx_gl_ntiers_int _seq } {##1}
        \int_set:Nn \l__lx_gl_maxwords_int
          { \int_max:nn { \l__lx_gl_maxwords_int }
              { \seq_count:c
                  { l__lx_gl_tier_ \int_use:N \l__lx_gl_ntiers_int _seq } } }
      }
    \leavevmode
    \group_begin:
    \raggedright
    \bool_set_true:N \l_lx_gl_inside_bool
    \int_gset:Nn \g__lxp_altg_role_int { 0 }
    \int_step_inline:nn { \l__lx_gl_maxwords_int }
      { % column ##1
        \lx@gl@colbegin
        \bool_if:NTF \l__lx_gl_phantom_bool
          {
            % Retrieve the object word WITHOUT expanding it: the auto-scan
            % must see the leading literal characters, not expand a macro
            % (e.g. \textbf{[}ein) and reach a "[" that the printed word only
            % shows through a control word.  Full expansion here would make
            % the scan fire on macro-wrapped brackets and double up with a
            % manual \GlossPhantom.  f-expansion evaluates \seq_item only.
            \exp_args:NNf \tl_set:Nn \l__lx_gl_obj_tl
              { \seq_item:cn { l__lx_gl_tier_1_seq } {##1} }
            \__lx_gl_leadprefix:N \l__lx_gl_obj_tl
          }
          { \tl_clear:N \l__lx_gl_prefix_tl }
        \vtop
          {
            \int_step_inline:nn { \l__lx_gl_ntiers_int }
              { % tier ####1
                \hbox:n
                  { \strut
                    \int_compare:nNnT {####1} > { 1 }
                      { \tl_if_empty:NF \l__lx_gl_prefix_tl
                          { \phantom
                              { \lx@glfontuse {1} { \l__lx_gl_prefix_tl } } } }
                    \lx@gl@wordbegin {####1}
                    \lx@glfontuse {####1}
                      { \seq_item:cn { l__lx_gl_tier_ ####1 _seq } {##1} }
                    \lx@gl@wordend {####1} }
              }
          }%
        \lx@gl@colend
        \hskip \GlossSep \relax
      }
    \unskip
    \par
    \group_end:
  }
\ExplSyntaxOff

%% User commands.  \gll and \glll keep their exact historical syntax and
%% are wrappers over the same engine; \gl ... \endgl takes any number of
%% lines, each terminated by \\ (a \\ before \endgl is optional).
\long\def\gll#1\\#2\\{\lx@gloss@multi{#1\\#2}}
\long\def\glll#1\\#2\\#3\\{\lx@gloss@multi{#1\\#2\\#3}}
\long\def\gl#1\endgl{\lx@gloss@multi{#1}}
\def\endgl{\PackageError{linguexx}{\string\endgl without \string\gl}{}}
\newcommand\glt{\par\nobreak\ignorespaces}
\let\gln\glt % cgloss4e-compat alias

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%  Stacked alternatives: \altn / \lxAltn                              %%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\ExplSyntaxOn
\seq_new:N  \l__lxp_alt_seq
\tl_new:N   \l__lxp_alt_align_tl
\tl_new:N   \l__lxp_alt_alt_tl
\box_new:N  \l__lxp_alt_box
\dim_new:N  \l__lxp_alt_ht_dim
\dim_new:N  \l__lxp_alt_dp_dim
\int_new:N  \l__lxp_alt_n_int

%% \lxAltn collects its brace-delimited alternatives (one leading mandatory
%% argument, then any number of further brace groups) and sets them as a
%% braced vertical stack.  This is deliberately NOT math: the stack is a
%% tabular and the brace is drawn with TikZ, so the alternatives are ordinary
%% tagged text.  Under active tagging the whole thing is wrapped in a Span
%% carrying a spoken /Alt ("A, B, or C"), built with \text_purify:n so that
%% formatting in an alternative (\sout, \textbf, ...) is stripped for speech.
\NewDocumentCommand \lxAltn { O{c} m }
  {
    \tl_set:Nn   \l__lxp_alt_align_tl {#1}
    \seq_clear:N \l__lxp_alt_seq
    \seq_put_right:Nn \l__lxp_alt_seq {#2}
    \__lxp_alt_grab:
  }
\cs_new_protected:Npn \__lxp_alt_grab:
  {
    \peek_catcode:NTF \c_group_begin_token
      { \__lxp_alt_grab_arg:n }
      { \__lxp_alt_print: }
  }
\cs_new_protected:Npn \__lxp_alt_grab_arg:n #1
  {
    \seq_put_right:Nn \l__lxp_alt_seq {#1}
    \__lxp_alt_grab:
  }
%% spoken alternate text: "A", "A or B", "A, B, or C"
\cs_new_protected:Npn \__lxp_alt_buildalt:
  {
    \tl_clear:N \l__lxp_alt_alt_tl
    \int_set:Nn \l__lxp_alt_n_int { \seq_count:N \l__lxp_alt_seq }
    \int_step_inline:nn { \l__lxp_alt_n_int }
      {
        \int_compare:nNnT { ##1 } > { 1 }
          {
            \int_compare:nNnTF { ##1 } = { \l__lxp_alt_n_int }
              {
                \int_compare:nNnTF { \l__lxp_alt_n_int } = { 2 }
                  { \tl_put_right:Nn \l__lxp_alt_alt_tl { ~or~ } }
                  { \tl_put_right:Nn \l__lxp_alt_alt_tl { ,~or~ } }
              }
              { \tl_put_right:Nn \l__lxp_alt_alt_tl { ,~ } }
          }
        \tl_put_right:Ne \l__lxp_alt_alt_tl
          { \text_purify:n { \seq_item:Nn \l__lxp_alt_seq {##1} } }
      }
  }
%% the stacked alternatives, as a tabular; also records total height.
%% Under active tagging, plain LaTeX auto-tags every tabular as a real
%% /Table (with /TR, /TD ...); this stack is presentational, not data, and
%% the auto Table is built (wrongly) as a child of whatever structure
%% element is open at THIS point -- typically the ambient paragraph, since
%% the surrounding Span for \altn has not been opened yet (that happens
%% later, in \__lxp_alt_emit_tagged:, around \box_use:N).  That produced
%% both an invalid Table-under-P/LI nesting and, whenever more than one
%% \altn occurred in a paragraph, corrupted paragraph-tagging bookkeeping
%% (veraPDF/tagpdf: "Parent-Child ... Relation is not allowed").  Building
%% the box with table auto-tagging suspended avoids this: the box then
%% carries no struct/MC of its own, so its content is correctly attributed
%% to the Span when \box_use:N later places it inside one.  \hbox_gset:Nn
%% (not \hbox_set:Nn) is required because the group that scopes the
%% \tagpdfsetup change would otherwise also discard the box.
\cs_new_protected:Npn \__lxp_alt_setstack:
  {
    \group_begin:
      \cs_if_exist:NT \tagpdfsetup { \tagpdfsetup { table/tagging = false } }
      \hbox_gset:Nn \l__lxp_alt_box
        {
          \use:x
            {
              \exp_not:N \begin { tabular } [c]
                { @{} \str_case:VnF \l__lxp_alt_align_tl { {l}{l} {r}{r} } {c} @{} }
            }
            \seq_use:Nn \l__lxp_alt_seq { \\ }
          \end { tabular }
        }
    \group_end:
    \dim_set:Nn \l__lxp_alt_dp_dim { \box_dp:N \l__lxp_alt_box }
    \dim_set:Nn \l__lxp_alt_ht_dim
      { \box_ht:N \l__lxp_alt_box + \l__lxp_alt_dp_dim }
  }
%% one brace, side L or R, drawn with TikZ to the stack height.  The
%% decoration bulges to the side determined by the path direction: an
%% upward path gives an opening brace, a downward path a closing one
%% (the v0.13 downward path drew the left brace mirrored).  The raise is
%% pinned to the stack's own depth, not half the total height: a stack is
%% seldom split evenly around its baseline (an all-caps or struck-through
%% row above pulls height, ordinary rows below add less depth), so using
%% the true box_dp keeps the brace's centre level with the stack's actual
%% midpoint instead of drifting toward whichever side is taller.
\cs_new_protected:Npn \__lxp_alt_brace:n #1
  {
    \raisebox { \dim_eval:n { \AltBraceRaise - \l__lxp_alt_dp_dim } }
      {
        \begin { tikzpicture }
          \useasboundingbox (0,0) rectangle ( \AltBraceWidth , \l__lxp_alt_ht_dim ) ;
          \str_if_eq:nnTF {#1} { L }
            { \draw [ decorate ,
                      decoration = { brace , amplitude = \AltBraceAmplitude } ]
                ( \dim_eval:n { \AltBraceWidth - 1pt } , 0pt )
                -- ( \dim_eval:n { \AltBraceWidth - 1pt } , \l__lxp_alt_ht_dim ) ; }
            { \draw [ decorate ,
                      decoration = { brace , amplitude = \AltBraceAmplitude } ]
                ( 1pt , \l__lxp_alt_ht_dim ) -- ( 1pt , 0pt ) ; }
        \end { tikzpicture }
      }
  }
%% the printed object (brace + stack + brace), no tagging.  The outer
%% gap (\AltBraceOuterSep) clears the decoration's outward bulge from
%% whatever precedes/follows; the inner gap (\AltBraceSep) just
%% separates the brace from the stack it braces.
\cs_new_protected:Npn \__lxp_alt_emit:
  { \leavevmode \hspace{\AltBraceOuterSep} \__lxp_alt_brace:n { L } \hspace{\AltBraceSep}
    \box_use:N \l__lxp_alt_box
    \hspace{\AltBraceSep} \__lxp_alt_brace:n { R } \hspace{\AltBraceOuterSep} }
%% the printed object wrapped in a Span carrying the spoken /Alt
\cs_new_protected:Npn \__lxp_alt_emit_tagged:
  {
    \__lxp_alt_buildalt:
    \leavevmode
    \hspace{\AltBraceOuterSep}
    \tag_mc_end_push:
    \exp_args:Ne \tag_struct_begin:n { tag = Span , alt = { \l__lxp_alt_alt_tl } }
    \tag_mc_begin:n { tag = Span }
    \__lxp_alt_brace:n { L } \hspace{\AltBraceSep}
    \box_use:N \l__lxp_alt_box
    \hspace{\AltBraceSep} \__lxp_alt_brace:n { R }
    \tag_mc_end:
    \tag_struct_end:
    \tag_mc_begin_pop:n {}
    \hspace{\AltBraceOuterSep}
  }
\cs_new_protected:Npn \__lxp_alt_print:
  {
    \__lxp_alt_setstack:
    \cs_if_exist:NTF \tag_if_active:T
      { \tag_if_active:TF { \__lxp_alt_emit_tagged: } { \__lxp_alt_emit: } }
      { \__lxp_alt_emit: }
  }
\ExplSyntaxOff

% Tunable dimensions of the drawn brace.  AltBraceSep is the INNER gap,
% between the brace and the stack it braces; AltBraceOuterSep is the
% OUTER gap, between the brace and whatever precedes/follows it in the
% surrounding text.  They differ because the TikZ brace decoration
% bulges outward past its own bounding box (the curl reaches further
% than the box declared for it) only on the outer side -- the inner
% side has no such overflow to clear, so it can sit much closer.
\newcommand\AltBraceWidth{0.9ex}
\newcommand\AltBraceAmplitude{4pt}
\newcommand\AltBraceSep{0.15em}
\newcommand\AltBraceOuterSep{0.7em}
\newcommand\AltBraceRaise{0pt}

% Alias \altn -> \lxAltn unless somebody already owns \altn.
\AtBeginDocument{%
  \@ifundefined{altn}%
    {\global\let\altn\lxAltn}%
    {\PackageInfo{linguexx}%
      {\string\altn\space is already defined;\MessageBreak
       only \string\lxAltn\space is available}}}


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%  Glossed alternatives: \altg / \lxAltg                              %%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\ExplSyntaxOn
\seq_new:N \l__lxp_altg_seq
\box_new:N \l__lxp_altg_stack_box
\box_new:N \l__lxp_altg_out_box
\dim_new:N \l__lxp_altg_ht_dim
\dim_new:N \l__lxp_altg_bxht_dim
\dim_new:N \l__lxp_altg_bxdp_dim
\tl_new:N  \l__lxp_altg_alt_tl
\int_new:N \l__lxp_altg_n_int
%% cross-cell protocol state (the gloss grid typesets column by column,
%% object cell first, so the two calls of one paradigm are adjacent)
\int_new:N \g__lxp_altg_role_int   % 0 = the next in-gloss \altg is the object call
\int_new:N \g__lxp_altg_count_int  % alternatives announced by the object call
\dim_new:N \g__lxp_altg_indent_dim % width of the object emit, for the gloss call
\bool_new:N \l_lx_gl_inside_bool   % true while \gll/\gl cells are typeset

%% \lxAltg{alt}{alt}... : one stacked column of alternatives.  Inside an
%% interlinear gloss it is written TWICE -- once in the object line with
%% the object words, once in the gloss line with their glosses:
%%
%%   \exg. Die \altg{Frau}{Socke}{Maus}{Tonne} ist da.\\
%%         The.\lpzg{sg} \altg{woman.\lpzg{sg}}{sock.\lpzg{sg}}%
%%           {mouse.\lpzg{sg}}{ton.\lpzg{sg}} is.\lpzg{prs} there.\\
%%
%% The two calls occupy the two tiers of one gloss column and assemble a
%% single paradigm: object column on the left, gloss column to its right
%% (offset by \AltgColSep), braced on BOTH sides, and centred on the
%% midline between the object tier and the gloss tier -- with four
%% alternatives, rows 2 and 3 ride the object and gloss lines and rows 1
%% and 4 protrude symmetrically, with surrounding lines kept clear.  The
%% example number, which \exg. places on the object baseline, stays put.
%% Both calls must have the same number of alternatives (package error
%% otherwise), and no spaces may separate the brace groups (a space ends
%% collection AND splits gloss columns; break lines with %).
%%
%% Outside a gloss, a single \lxAltg sets one both-braced stack on the
%% current baseline, like \lxAltn with a closing brace added.
%%
%% Like \lxAltn this is deliberately NOT math.  Inside the stacks \lpzg is
%% reduced to plain small caps (each stack forms a single marked-content
%% span under tagging, so nested abbreviation Spans are suppressed);
%% expansions reappear in the spoken form.  Under active tagging each
%% call is wrapped in a Span carrying /Alt speaking its own list ("Frau,
%% Socke, Maus, or Tonne" / "woman.singular, ..."), with simple \lpzg
%% keys expanded from the Leipzig table and compound or unknown keys
%% passed through verbatim.
\NewDocumentCommand \lxAltg { m }
  {
    \seq_clear:N \l__lxp_altg_seq
    \seq_put_right:Nn \l__lxp_altg_seq {#1}
    \__lxp_altg_grab:
  }
\cs_new_protected:Npn \__lxp_altg_grab:
  { \peek_catcode:NTF \c_group_begin_token
      { \__lxp_altg_grab_arg:n } { \__lxp_altg_print: } }
\cs_new_protected:Npn \__lxp_altg_grab_arg:n #1
  {
    \seq_put_right:Nn \l__lxp_altg_seq {#1}
    \__lxp_altg_grab:
  }
%% spoken alternate text: "A", "A or B", "A, B, or C"; \lpzg keys found
%% in the Leipzig table speak as their expansion, others as printed.
\cs_new_protected:Npn \__lxp_altg_buildalt:
  {
    \tl_clear:N \l__lxp_altg_alt_tl
    \int_set:Nn \l__lxp_altg_n_int { \seq_count:N \l__lxp_altg_seq }
    \group_begin:
      \cs_set:Npn \lpzg ##1
        { \prop_if_in:NnTF \g_lx_lpzg_prop {##1}
            { \prop_item:Nn \g_lx_lpzg_prop {##1} } {##1} }
      \int_step_inline:nn { \l__lxp_altg_n_int }
        {
          \int_compare:nNnT { ##1 } > { 1 }
            {
              \int_compare:nNnTF { ##1 } = { \l__lxp_altg_n_int }
                { \int_compare:nNnTF { \l__lxp_altg_n_int } = { 2 }
                    { \tl_gput_right:Nn \l__lxp_altg_alt_tl { ~or~ } }
                    { \tl_gput_right:Nn \l__lxp_altg_alt_tl { ,~or~ } } }
                { \tl_gput_right:Nn \l__lxp_altg_alt_tl { ,~ } }
            }
          \tl_gput_right:Ne \l__lxp_altg_alt_tl
            { \text_purify:n { \seq_item:Nn \l__lxp_altg_seq {##1} } }
        }
    \group_end:
  }
%% the stack: one [c]-centred tabular; per-side extents recorded.  Table
%% auto-tagging is suspended while building it, for the same reason as in
%% \__lxp_alt_setstack: above (see the comment there): the tabular is
%% presentational, the enclosing Span is not open yet at this point, and
%% \hbox_gset:Nn is required so the box survives the group that scopes the
%% \tagpdfsetup change.
\cs_new_protected:Npn \__lxp_altg_setstack:n #1
  {
    \group_begin:
      \cs_if_exist:NT \tagpdfsetup { \tagpdfsetup { table/tagging = false } }
      \hbox_gset:Nn \l__lxp_altg_stack_box
        %% \lx@lpzg@build parses the label without printing anything: the
        %% abbreviation is set plain here, but it still counts as used and
        %% reaches \lpzglist like any other.
        { #1 \renewcommand \lpzg [1]
            { \lx@lpzg@build {##1} \textsc {##1} }
          \use:x { \exp_not:N \begin { tabular } [c] { @{}l@{} }
                   \seq_use:Nn \l__lxp_altg_seq { \\ } }
          \end { tabular } }
    \group_end:
    \dim_set:Nn \l__lxp_altg_bxht_dim { \box_ht:N \l__lxp_altg_stack_box }
    \dim_set:Nn \l__lxp_altg_bxdp_dim { \box_dp:N \l__lxp_altg_stack_box }
    \dim_set:Nn \l__lxp_altg_ht_dim
      { \l__lxp_altg_bxht_dim + \l__lxp_altg_bxdp_dim }
  }
%% one brace, side L or R, on the baseline, sized to the stack's extents.
%% Path direction sets the bulge: upward = opening, downward = closing.
\cs_new_protected:Npn \__lxp_altg_brace:n #1
  {
    \begin { tikzpicture } [ baseline = 0pt ]
      \useasboundingbox
        ( 0pt , \dim_eval:n { - \l__lxp_altg_bxdp_dim } )
        rectangle ( \AltBraceWidth , \l__lxp_altg_bxht_dim ) ;
      \str_if_eq:nnTF {#1} { L }
        { \draw [ decorate , decoration = { brace , amplitude = \AltBraceAmplitude } ]
            ( \dim_eval:n { \AltBraceWidth - 1pt } ,
              \dim_eval:n { - \l__lxp_altg_bxdp_dim } )
            -- ( \dim_eval:n { \AltBraceWidth - 1pt } , \l__lxp_altg_bxht_dim ) ; }
        { \draw [ decorate , decoration = { brace , amplitude = \AltBraceAmplitude } ]
            ( 1pt , \l__lxp_altg_bxht_dim )
            -- ( 1pt , \dim_eval:n { - \l__lxp_altg_bxdp_dim } ) ; }
    \end { tikzpicture }
  }
%% the three printed shapes.  Object cell: left brace + stack, dropped
%% half a baseline; natural height kept (reserves the protrusion above),
%% depth clamped to zero so the gloss tier lands on the grid.  Gloss
%% cell: indent by the object emit's width + \AltgColSep, then stack +
%% right brace, raised half a baseline; height clamped (grid), natural
%% depth kept (reserves the protrusion below).  Solo: both braces on the
%% current baseline.
\cs_new_protected:Npn \__lxp_altg_shape_obj:
  {
    \hbox_set:Nn \l__lxp_altg_out_box
      { \hspace { \AltBraceOuterSep }
        \raisebox { \dim_eval:n { -0.5 \baselineskip } }
          { \__lxp_altg_brace:n { L } \hspace { \AltBraceSep }
            \box_use:N \l__lxp_altg_stack_box } }
    \dim_gset:Nn \g__lxp_altg_indent_dim
      { \box_wd:N \l__lxp_altg_out_box + \AltgColSep }
    \box_set_dp:Nn \l__lxp_altg_out_box { 0pt }
    \box_use:N \l__lxp_altg_out_box
  }
\cs_new_protected:Npn \__lxp_altg_shape_gloss:
  {
    \hbox_set:Nn \l__lxp_altg_out_box
      { \skip_horizontal:n { \g__lxp_altg_indent_dim }
        \raisebox { \dim_eval:n { 0.5 \baselineskip } }
          { \box_use:N \l__lxp_altg_stack_box \hspace { \AltBraceSep }
            \__lxp_altg_brace:n { R } }
        \hspace { \AltBraceOuterSep } }
    \box_set_ht:Nn \l__lxp_altg_out_box { 0pt }
    \box_use:N \l__lxp_altg_out_box
  }
\cs_new_protected:Npn \__lxp_altg_shape_solo:
  {
    \hspace { \AltBraceOuterSep }
    \__lxp_altg_brace:n { L } \hspace { \AltBraceSep }
    \box_use:N \l__lxp_altg_stack_box
    \hspace { \AltBraceSep } \__lxp_altg_brace:n { R }
    \hspace { \AltBraceOuterSep }
  }
%% emit one shape, tag-guarded: under active tagging the shape is wrapped
%% in a Span carrying the spoken /Alt of this call's list.
\cs_new_protected:Npn \__lxp_altg_emit:n #1
  {
    \leavevmode
    \bool_lazy_and:nnTF
      { \cs_if_exist_p:N \tag_if_active:T }
      { \tag_if_active_p: }
      {
        \__lxp_altg_buildalt:
        \tag_mc_end_push:
        \exp_args:Ne \tag_struct_begin:n
          { tag = Span , alt = { \l__lxp_altg_alt_tl } }
        \tag_mc_begin:n { tag = Span }
        #1
        \tag_mc_end:
        \tag_struct_end:
        \tag_mc_begin_pop:n {}
      }
      { #1 }
  }
\cs_new_protected:Npn \__lxp_altg_print:
  {
    \bool_if:NTF \l_lx_gl_inside_bool
      {
        \int_compare:nNnTF { \g__lxp_altg_role_int } = { 0 }
          { % object call
            \int_gset:Nn \g__lxp_altg_role_int { 1 }
            \int_gset:Nn \g__lxp_altg_count_int
              { \seq_count:N \l__lxp_altg_seq }
            \__lxp_altg_setstack:n { }
            \__lxp_altg_emit:n { \__lxp_altg_shape_obj: }
          }
          { % gloss call
            \int_gset:Nn \g__lxp_altg_role_int { 0 }
            \int_compare:nNnF { \seq_count:N \l__lxp_altg_seq }
                            = { \g__lxp_altg_count_int }
              { \PackageError { linguexx }
                  { \string\altg : \int_use:N \g__lxp_altg_count_int\space
                    object~alternatives~but~
                    \int_eval:n { \seq_count:N \l__lxp_altg_seq } ~glosses }
                  { The~two~\string\altg\space calls~of~one~paradigm~must~
                    list~the~same~number~of~alternatives. } }
            \__lxp_altg_setstack:n { \AltgTransFont }
            \__lxp_altg_emit:n { \__lxp_altg_shape_gloss: }
          }
      }
      { % solo, outside a gloss
        \__lxp_altg_setstack:n { }
        \__lxp_altg_emit:n { \__lxp_altg_shape_solo: }
      }
  }
\ExplSyntaxOff

% Tunables.  The braces share \AltBraceWidth/\AltBraceAmplitude/\AltBraceSep
% with \lxAltn (declared above).
\newcommand\AltgColSep{1.2em}%   glue between object and gloss columns
\newcommand\AltgTransFont{\normalfont}% font of the gloss stack

% Alias \altg -> \lxAltg unless somebody already owns \altg.
\AtBeginDocument{%
  \@ifundefined{altg}%
    {\global\let\altg\lxAltg}%
    {\PackageInfo{linguexx}%
      {\string\altg\space is already defined;\MessageBreak
       only \string\lxAltg\space is available}}}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%  Explicit judgment markers: \jdg                                    %%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\newlength{\JdgSep}% value set in the defaults block (Layout section)
%% \jdg[<spoken>]{<mark>} hangs <mark> in the margin.  With an explicit
%% <spoken> (or a known default for <mark>), the mark is announced by a
%% screen reader as that phrase; otherwise it is typeset as before.
\ExplSyntaxOn
\NewDocumentCommand \jdg { O{} m }
  {
    \tl_if_blank:nTF {#1}
      { \exp_args:Ne \lx@hangjudge { \prop_item:Ne \g_lx_judge_alt_prop { \tl_to_str:n {#2} } } {#2} }
      { \lx@hangjudge {#1} {#2} }
  }
%% \DeclareJudgment[spoken=<phrase>]{\cmd}{<mark>} names a mark.  The
%% spoken phrase, if given, is both attached to \cmd and registered for
%% <mark> so a leading scanned <mark> is announced the same way.
\keys_define:nn { lx / judge }
  { spoken .tl_set:N = \l__lx_judge_decl_tl }
\NewDocumentCommand \DeclareJudgment { O{} m m }
  {
    \tl_clear:N \l__lx_judge_decl_tl
    \keys_set:nn { lx / judge } {#1}
    \tl_if_empty:NF \l__lx_judge_decl_tl
      { \exp_args:Nne \lx@judge@setalt {#3} { \l__lx_judge_decl_tl } }
    \exp_args:Nne \DeclareRobustCommand #2
      { \exp_not:N \jdg [ \l__lx_judge_decl_tl ] { \exp_not:n {#3} } }
  }
\cs_set_eq:NN \DeclareJudgement \DeclareJudgment
%% \SetJudgmentSpoken{<mark>}{<phrase>} overrides or adds a spoken form.
\NewDocumentCommand \SetJudgmentSpoken { m m }
  { \lx@judge@setalt {#1} {#2} }
\ExplSyntaxOff

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%  Cross-reference ranges                                             %%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\newcommand\rangedash{--}
\newcommand\lx@setsub[2]{\expandafter\gdef\csname lx@sub@#1\endcsname{#2}}
\newcommand\sublabel[1]{\label{#1}%
  \if@filesw
    \immediate\write\@auxout{\string\lx@setsub{#1}{\Exalph{SubExNo}}}%
  \fi}
\newcommand\lx@subletter[1]{%
  \ifcsname lx@sub@#1\endcsname
    \csname lx@sub@#1\endcsname
  \else
    \pref{#1}%
  \fi}
\newcommand\prefrange[2]{\pref{#1}\rangedash\lx@subletter{#2}}
\newcommand\refrange[2]{(\prefrange{#1}{#2})}
\newcommand\Refrange[2]{\ref{#1}\rangedash\ref{#2}}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%  Right-aligned in-line source: \exsource                            %%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\newcommand{\ExSourceFont}{\normalfont\footnotesize}
\DeclareRobustCommand{\exsource}[1]{%
  \unskip\nobreak\hskip0pt plus 1fill\relax
  \penalty50
  \hskip1em plus 1fill\relax
  \hbox{}\nobreak\hskip0pt plus 1fill\relax
  \mbox{\ExSourceFont#1}}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%  Install the defaults of the mode in force                          %%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Done here, at the end, so that every length and macro it touches exists.
%% Because this runs at LOAD time (and not \AtBeginDocument, as in
%% linguex), a \setlength in the preamble overrides it, as one would
%% expect.

\resetExdefaults

%%%% EOF