Patch \text

luamml-patches-amstext.sty

@@ -0,0 +1,37 @@
+\ProvidesExplPackage {luamml-patches-amstext} {2021-04-23} {0.0.1-alpha}
+  {Feel free to add a description here}
+
+\int_new:N \g__luamml_amsmath_text_struct_int
+\cs_set:Npn \textdef@ #1 #2 #3 {
+  \int_if_odd:nTF { \int_div_truncate:nn { \l__luamml_flag_int } { 8 } } {
+    \int_gincr:N \g__luamml_amsmath_text_struct_int
+    \tag_struct_begin:n {
+      tag = mtext/mathml,
+      stash,
+      label = __luamml_amsmath_text_ \int_use:N \g__luamml_amsmath_text_struct_int
+    }
+    \tag_mc_begin:n {
+      tag = mtext
+    }
+    \AnnotateFormula {
+      nucleus = true,
+      struct = "__luamml_amsmath_text_ \int_use:N \g__luamml_amsmath_text_struct_int"
+    }
+  } {
+    \use_i:n
+  }
+  {
+    \hbox {
+      {
+        \everymath {#1}
+        \let \f@size #2
+        \selectfont
+        #3
+      }
+    }
+  }
+  \int_if_odd:nT { \int_div_truncate:nn { \l__luamml_flag_int } { 8 } } {
+    \tag_mc_end:
+    \tag_struct_end:
+  }
+}

luamml-tex-annotate.lua

@@ -59,7 +59,21 @@ local function annotate()
         props = {}
         properties[marked] = props
       end
-      props.mathml_core = annotation.core
+      if annotation.core then
+        props.mathml_core = annotation.core
+      end
+      if annotation.struct then
+        local saved = props.mathml_filter
+        local struct = annotation.struct
+        function props.mathml_filter(mml, core)
+          mml[':struct'] = struct
+          if saved then
+            return saved(mml, core)
+          else
+            return mml, core
+          end
+        end
+      end
     else
       tex.error'Unable to annotate nucleus of node without nucleus'
     end

luamml.dtx

@@ -450,6 +450,7 @@
 %    \begin{macrocode}
 \RequirePackage { luamml-patches-kernel }
 %<*luatex>
+\__luamml_patch_package:n {amstext}
 \__luamml_patch_package:n {amsmath}
 \__luamml_patch_package:n {array}
 %</luatex>

testfiles-lua/test_struct.pvt

@@ -18,6 +18,13 @@
 
 \begin{document}
 \tagstructbegin{tag=Document}
+
+\tagstructbegin{tag=P}
+\tagmcbegin{tag=P}
+hello
+\tagmcend
+\tagstructend
+
 \LuaMMLTagAF{} {
 \[
   \begin{pmatrix}
@@ -27,8 +34,8 @@
   \end{pmatrix}
   =
   \begin{cases}
-    1 & $if $a=b\\
-    2 & $else$
+    1 & \text{if $a=b$} \\
+    2 & \text{else}
   \end{cases}
 \]
 }