handle labels in alignment

base/lttagging.dtx

@@ -566,6 +566,8 @@
 % \NewSocket{tagsupport/math/display/end}{0}
 % \NewSocket{tagsupport/math/display/formula/begin}{2} %
 % \NewSocket{tagsupport/math/display/formula/end}{0}
+% \NewSocket{tagsupport/math/display/tag/begin}{0} %
+% \NewSocket{tagsupport/math/display/tag/end}{0}
 %    \end{macrocode}
 %
 % \subsubsection{Sockets specific for luamml}

required/latex-lab/latex-lab-amsmath.dtx

@@ -88,22 +88,31 @@
 %  The tag/label must be saved, so that it can be reinserted later.
 %  TODO: xml export looks ok, but tagging with structure elements 
 %  is wrong and must be corrected.
+%  TODO: \cs{maketag@@@} is used in places where tagging/luamml handling
+%  is not wanted. This must be checked and handled.
 %    \begin{macrocode}
-\@namedef{maketag@@@} #1
+\def\maketag@@@#1
   {%
     \ifmeasuring@
       \hbox{\m@th\normalfont#1}%
     \else
-      \tagmcend \tagstructbegin{tag=Lbl}%
-      \tagmcbegin{tag=Lbl}%
+      \UseTaggingSocket{math/display/tag/begin}
       \hbox{\m@th\normalfont#1
       \UseTaggingSocket{math/luamml/mtable/tag/save}
       }%
-      \tagmcend \tagstructend \tagmcbegin{}%
+      \UseTaggingSocket{math/display/tag/end}
     \fi
    }
 %    \end{macrocode}
-%
+% \cs{eqref} uses \cs{tagform@} and so \cs{maketag@@@} but we do not want this tagging
+% there. 
+% 
+%    \begin{macrocode}
+\def\maketag@@@notag#1{\hbox{\m@th\normalfont#1}}
+\DeclareRobustCommand{\eqref}[1]
+  {\textup{\let\maketag@@@\maketag@@@notag\tagform@{\ref{#1}}}}
+%    \end{macrocode}
+% 
 % \subsubsection{align \& friends}
 % The align preamble (used in \cs{align@}) needs code for luamml 
 % to save the cells.

required/latex-lab/latex-lab-math.dtx

@@ -1505,6 +1505,46 @@
 %    \end{macrocode}
 % \end{plugdecl}
 %
+% \subsubsection{Sockets for tags (labels)}
+% \begin{socketdecl}
+%   {
+%     tagsupport/math/display/tag/begin,
+%     tagsupport/math/display/tag/end,
+%   }
+%   These sockets are used in \cs{maketag@@@} to tag
+%   labels as Lbl. luamml changes the plug to move
+%   the Lbl into the math structure with an intent. 
+%   \changes{v0.6l}{2025-02-06}{added sockets for tags/labels}
+%    \begin{macrocode}
+\socket_new:nn {tagsupport/math/display/tag/begin}{0}
+\socket_new:nn {tagsupport/math/display/tag/end}{0}
+%    \end{macrocode}
+%\end{socketdecl}
+%
+% \begin{plugdecl}{default}
+% \changes{v0.6j}{2024-11-19}{moved \cs{tagpdfparaOff} into the socket, tagging/765}
+%    \begin{macrocode}
+\socket_new_plug:nnn
+  {tagsupport/math/display/tag/begin}
+  {default}
+  {
+    \tag_mc_end: 
+    \tag_struct_begin:n {tag=Lbl}
+    \tag_mc_begin:n {}
+  }
+\socket_new_plug:nnn
+  {tagsupport/math/display/tag/end}
+  {default}
+  {
+    \tag_mc_end: 
+    \tag_struct_end: 
+    \tag_mc_begin:n{}
+  }
+\socket_assign_plug:nn {tagsupport/math/display/tag/begin}{default}  
+\socket_assign_plug:nn {tagsupport/math/display/tag/end}{default}
+%    \end{macrocode}
+% \end{plugdecl}
+%
 % \subsubsection{Internal sockets}
 %
 % \begin{variable}{\l_@@_content_template_tl}

texmf/tex/lualatex/luamml/luamml-structelemwriter.lua

@@ -8,6 +8,9 @@ local mc_end = token.create'tag_mc_end:'
 
 local catlatex       = luatexbase.registernumber("catcodetable@latex")
 
+ltx.__tag.struct.luamml = ltx.__tag.struct.luamml or {}
+ltx.__tag.struct.luamml.labels = ltx.__tag.struct.luamml.labels or {}
+
 local function escape_name(name)
   return name
 end
@@ -117,10 +120,13 @@ local function write_elem(tree, stash)
   end
   for _, elem in ipairs(tree) do
     if type(elem) ~= 'string'  and not elem['tex:ignore']  then
-      if elem['intent']==':equationlabel' and lastlblstructnum then
-        elem[1][#elem+1]={[':structnum']= lastlblstructnum}
-        lastlblstructnum=nil
-      end  
+      if elem['intent']==':equationlabel' and ltx.__tag.struct.luamml.labels then
+        if #ltx.__tag.struct.luamml.labels > 0 then         
+         -- print("CHECK LABEL STRUCTURE: ",table.serialize(elem), table.serialize(ltx.__tag.struct.luamml.labels))
+        local num= table.remove(ltx.__tag.struct.luamml.labels,1) 
+        elem[1][#elem+1]={[':structnum']= num}
+        end
+      end 
       write_elem(elem)
     end
   end

texmf/tex/lualatex/luamml/luamml.sty

@@ -231,6 +231,35 @@
  }
 \AssignSocketPlug{tagsupport/math/luamml/mtable/tag/set}{luamml}
 
+\clist_map_inline:nn
+  {
+    align,
+    alignat,
+    xalignat,
+    xxalignat,
+    flalign,
+    gather,
+    %multline, % NO
+    %equation, % NO
+  }
+  {\tl_const:cn { c__luamml_label_#1_tl}{}}
+\NewSocketPlug{tagsupport/math/display/tag/begin}{luamml}
+ {
+   \tag_mc_end:
+   \bool_lazy_and:nnTF
+    { \tl_if_exist_p:c { c__luamml_label_ \@currenvir _tl } }
+    { \int_if_odd_p:n { \int_div_truncate:nn { \l__luamml_flag_int } { 8 } } }
+    {
+      \typeout{Stash~and~move~\@currenvir~Lbl}
+      \tag_struct_begin:n {tag=Lbl,stash}
+      \directlua{table.insert(ltx.__tag.struct.luamml.labels,\tag_get:n{struct_num})}
+    }
+    {
+      \tag_struct_begin:n {tag=Lbl}
+    }
+   \tag_mc_begin:n {}
+ }
+\AssignSocketPlug{tagsupport/math/display/tag/begin}{luamml}
 \str_if_exist:cF { l__socket_tagsupport/math/luamml/hbox_plug_str }
  {
    \NewSocket{tagsupport/math/luamml/hbox}{2}