\ProvidesExplPackage {luamml-patches-amsmath} {2025-02-17} {0.3.0}
  {Feel free to add a description here}

\lua_now:n { require'luamml-amsmath' }

% For all of these changes, the redefinitions appear huge.
% But they are almost identical to the original and only
% add luamml commands in appropriate places, so they would
% mostly disappear if there were enough hooks in amsmath.
\IfPackageAtLeastTF{latex-lab-testphase-math}{2025-01-24}
 {}
 {
   \PackageInfo{luamml}{patching~\string\start@aligned}
    % aligned and friends
    \cs_set:Npn \start@aligned #1#2 {
      \RIfM@
      \else
        \nonmatherr@ { \begin { \@currenvir } }
      \fi
      \savecolumn@ % Assumption: called inside a group
        \UseTaggingSocket{ math/luamml/annotate/false } {}{ \alignedspace@left }
      \ams@start@box {#1} \bgroup
        \maxfields@ #2 \relax
        \ifnum \maxfields@ > \m@ne
          \multiply \maxfields@ \tw@
          \let \math@cr@@@ \math@cr@@@alignedat
          \alignsep@ \z@skip
        \else
          \let \math@cr@@@ \math@cr@@@aligned
          \alignsep@ \minalignsep
        \fi
        \Let@ \chardef \dspbrk@context \@ne
        \default@tag
        \spread@equation % no-op if already called
        \global \column@ \z@
        \ialign \bgroup
          & \column@plus
            \hfil
            \strut@
            $
              \m@th
              \displaystyle
              {##}
              \UseTaggingSocket{math/luamml/save/nNn}{ {} \displaystyle {mtd}}
            $
            \UseTaggingSocket{math/luamml/mtable/finalizecol}{last}
            \tabskip \z@skip
          & \column@plus
            $
              \m@th
              \displaystyle
              {
                {}
                ##
              }
              \UseTaggingSocket{math/luamml/save/nNn}{ {} \displaystyle {mtd}}
            $
            \UseTaggingSocket{math/luamml/mtable/finalizecol}{last}
            \hfil
            \tabskip\alignsep@
          \crcr
          \ams@return@opt@arg
    }
   \PackageInfo{luamml}{patching~gathered}
     \renewcommand \gathered [1] [c] {
       \RIfM@
       \else
         \nonmatherr@ { \begin {gathered} }
       \fi
       \UseTaggingSocket{ math/luamml/annotate/false } {}{ \alignedspace@left }
       \ams@start@box {#1} \bgroup
         \Let@
         \chardef \dspbrk@context \@ne
         \restore@math@cr
         \spread@equation
         \ialign \bgroup
             \hfil
             \strut@
             $
               \m@th
               \displaystyle
               ##
               \UseTaggingSocket{math/luamml/save/nNn}{ {} \displaystyle {mtd}}
             $
             \UseTaggingSocket{math/luamml/mtable/finalizecol}{last}
             \hfil
           \crcr
             \ams@return@opt@arg
     }
   \PackageInfo{luamml}{patching~\string\endaligned}
   \cs_set:Npn \endaligned {
         \crcr
         \UseExpandableTaggingSocket{math/luamml/mtable/innertable/save}
       \egroup
       \restorecolumn@
     \egroup
     \UseTaggingSocket{math/luamml/mtable/innertable/finalize}
   }
   \PackageInfo{luamml}{patching~\string\gather@}
     \cs_set:Npn \gather@ #1 {
       \ingather@true
       \let \split \insplit@
       \let \tag \tag@in@align
       \let \label \label@in@display
       \chardef \dspbrk@context \z@
       \intertext@ \displ@y@ \Let@
       \let \math@cr@@@ \math@cr@@@gather
       \gmeasure@ {#1}
       \global \shifttag@false
       \tabskip \z@skip
       \global \row@ \@ne
       \halign to \displaywidth \bgroup
           \strut@
           \setboxz@h {
             $
               \m@th
               \displaystyle
               {##}
               \UseTaggingSocket{math/luamml/save/nNn}{ {} \displaystyle {mtd}}
             $
           }
           \UseTaggingSocket{math/luamml/mtable/finalizecol}{box}
           \calc@shift@gather
           \set@gather@field
           \tabskip\@centering
         &
           \setboxz@h {
             \strut@
             {##}
           }
           \dim_compare:nNnTF {0pt} = {
             \box_wd:N \c_zero_int
           }
           { \place@tag@gather }
           {
             \place@tag@gather
             \UseTaggingSocket{math/luamml/mtable/tag/set}
           }
           \tabskip \iftagsleft@
             \gdisplaywidth@
           \else
             \z@skip
           \span \fi
           \crcr
           #1
     }
% in latex lab, add the luamml_ignore to \measuring@true instead.
    \PackageInfo{luamml}{patching~\string\gmeasure@}
    \cs_new_eq:NN \__luamml_amsmath_original_gmeasure:n \gmeasure@
    \cs_set:Npn \gmeasure@ #1 {
      \exp_last_unbraced:Nno
        \use_ii_i:nn
        { \luamml_ignore: }
        { \__luamml_amsmath_original_gmeasure:n {#1} }
    }


   \PackageInfo{luamml}{patching~\string\endgather}
   \cs_set:Npn \endgather {
         \math@cr
         \black@ \totwidth@
         \UseExpandableTaggingSocket{math/luamml/mtable/finalize} {gather}
     \egroup
     $$
     \ignorespacesafterend
   }


% align and friends
   \PackageInfo{luamml}{patching~\string\align@preamble}
   \cs_set:Npn \align@preamble {
     &
       \hfil
       \strut@
       \setboxz@h {
         \@lign
         $
           \m@th
           \displaystyle
           {##}
           \ifmeasuring@
             \luamml_ignore:
           \else
             \UseTaggingSocket{math/luamml/save/nNn}{ {} \displaystyle {mtd}}
           \fi
         $
       }
       \ifmeasuring@
         \savefieldlength@
       \else
         \UseTaggingSocket{math/luamml/mtable/finalizecol}{box}
       \fi
       \set@field
       \tabskip\z@skip
     &
       \setboxz@h {
         \@lign
         $
         \m@th
         \displaystyle
         {
           {}
           ##
         }
         \ifmeasuring@
           \luamml_ignore:
         \else
           \UseTaggingSocket{math/luamml/save/nNn}{ {} \displaystyle {mtd}}
         \fi
         $
       }
       \ifmeasuring@
         \savefieldlength@
       \else
         \UseTaggingSocket{math/luamml/mtable/finalizecol}{box}
       \fi
       \set@field
       \hfil
       \tabskip\alignsep@
   }
   \PackageInfo{luamml}{patching~\string\math@cr@@@align}
   \cs_set:Npn \math@cr@@@align {
     \ifst@rred
       \nonumber
     \fi
     \if@eqnsw
       \global \tag@true
     \fi
     \global \advance \row@ \@ne
     \add@amps \maxfields@
     \omit
     \kern -\alignsep@
     \iftag@
       \setboxz@h {
         \@lign
         \strut@
         { \make@display@tag }
       }
       \place@tag
       \UseTaggingSocket{math/luamml/mtable/tag/set}
     \fi
     \ifst@rred
     \else
       \global \@eqnswtrue
     \fi
     \global \lineht@ \z@
     \cr
   }

% This was lost anyway, as the latex-lab code overwrites
% the definition again.
   \PackageInfo{luamml}{patching~\string\maketag@@@}
   \cs_set:Npn \maketag@@@ #1
    {
      \hbox {
       \m@th
       \normalfont
       #1
       \UseTaggingSocket{math/luamml/mtable/tag/save}
     }
    }
   \PackageInfo{luamml}{patching~\string\endalign}
% this handled in latex-lab through \common@align@ending
    \cs_set:Npn \endalign {
      \math@cr
      \black@ \totwidth@
      \UseTaggingSocket{math/luamml/mtable/finalize} {align}
      \egroup
      \ifingather@
        \restorealignstate@
        \egroup
        \nonumber
        \ifnum0=`{\fi\iffalse}\fi
      \else
        $$
      \fi
      \ignorespacesafterend
    }
   
   \PackageInfo{luamml}{patching~\string\multline@}
   % For a more interesting one, let's consider multline:
   \cs_new_eq:NN \__luamml_amsmath_original_multline:n \multline@
   \cs_set:Npn \multline@ #1 {
     \__luamml_amsmath_original_multline:n {
       \ifmeasuring@ \else
         \UseTaggingSocket{math/luamml/mtable/aligncol} {left}
       \fi
       #1
       \ifmeasuring@ \else
         \UseTaggingSocket{math/luamml/mtable/aligncol} {right}
       \fi
     }
   }

   %this is not move to latex-lab as the luamml_ignore is inserting with 
   % \measuringtrue
   \PackageInfo{luamml}{patching~\string\mmeasure@}
   \cs_new_eq:NN \__luamml_amsmath_original_mmeasure:n \mmeasure@
   \cs_set:Npn \mmeasure@ #1 {
     \exp_last_unbraced:Nno
       \use_ii_i:nn
       { \luamml_ignore: }
       { \__luamml_amsmath_original_mmeasure:n {#1} }
   }
% Luckily, {multline} uses \endmultline@math in exactly
% the spot where we have to set the flag.
% Less luckily, \endmultline@math sometimes get overwritten for the last line.
% But that isn't a problem since we want special behavior there anyway.
    \PackageInfo{luamml}{patching~\string\endmultline@math}
    \cs_set:Npn \endmultline@math {
      \UseTaggingSocket{math/luamml/save/nNn}{{} \displaystyle {mtd}}
      $
      \UseTaggingSocket{math/luamml/mtable/finalizecol}{last}
    }
    \PackageInfo{luamml}{patching~\string\rendmultline@}
    \cs_set:Npn \rendmultline@ {
        \iftag@
          \UseTaggingSocket{math/luamml/save/nNn}{{} \displaystyle {mtd}}
          $
          \UseTaggingSocket{math/luamml/mtable/finalizecol}{last}
          \let \endmultline@math \relax
          \ifshifttag@
            \hskip \multlinegap
            \llap {
              \vtop {
                \raise@tag
                \normalbaselines
                \setbox \@ne \null
                \dp \@ne \lineht@
                \box \@ne
                \hbox {
                  \strut@
                  \make@display@tag
                }
              }
            }
          \else
            \hskip \multlinetaggap
            \make@display@tag
          \fi
          \UseTaggingSocket{math/luamml/mtable/tag/set}
        \else
          \hskip \multlinegap
        \fi
        \hfilneg
        \math@cr
        \UseExpandableTaggingSocket {math/luamml/mtable/finalize} {multline}
      \egroup
      $$
    }
    \PackageInfo{luamml}{patching~\string\lendmultline@}
    \cs_set:Npn \lendmultline@ {
        \hfilneg
        \hskip\multlinegap
        \math@cr
        \UseExpandableTaggingSocket {math/luamml/mtable/finalize} {multline}
        %\__luamml_amsmath_finalize_table:n {multline}
      \egroup
      $$
    }
   
   \PackageInfo{luamml}{patching~smallmatrix}
    \renewenvironment {smallmatrix} {
      \UseTaggingSocket{ math/luamml/annotate/false } {} { \null\, }
      \vcenter \bgroup
        \Let@
        \restore@math@cr
        \default@tag
        \baselineskip 6 \ex@
        \lineskip 1.5 \ex@
        \lineskiplimit \lineskip
        \ialign \bgroup
            \hfil
            $
            \m@th
            \scriptstyle
            ##
            % No \scriptsize here since we want to add the mstyle nodes
            \UseTaggingSocket{math/luamml/save/nn}{ {} {mtd}}
            $
            \UseTaggingSocket{math/luamml/mtable/finalizecol}{last}
            \hfil
          &&
            \thickspace
            \hfil
            $
            \m@th
            \scriptstyle
            ##
            % No \scriptsize here since we want to add the mstyle nodes
            \UseTaggingSocket{math/luamml/save/nn}{ {} {mtd}}
            $
            \UseTaggingSocket{math/luamml/mtable/finalizecol}{last}
            \hfil
          \crcr
    }{%
          \crcr
          \UseExpandableTaggingSocket{math/luamml/mtable/smallmatrix/save}
        \egroup
      \egroup
      \UseTaggingSocket{math/luamml/mtable/innertable/finalize}
      \UseTaggingSocket{math/luamml/annotate/false} {}{ \, }
    }

    % {cases} is defined by the kernel, but we patch the overwritten version by amsmath.
    \PackageInfo{luamml}{patching~\string\env@cases}
    \cs_set:Npn \env@cases {
      \let \@ifnextchar \new@ifnextchar
      \left \lbrace
        \def \arraystretch {1.2}
        \array {@{}l@{\quad \luamml_ignore:}l@{}}
    }
   \PackageInfo{luamml}{patching~\string\bBigg@}
   \cs_set:Npn \bBigg@ #1 #2 {
     {
       \ensuremath {
         \Uvextensible height~#1 \big@size axis~exact~#2
       }
     }
   }
} %end package test