From 26e1ffad33bca455ed76473bb91a6d2e57f0e0e3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marcel=20Fabian=20Kr=C3=BCger?= <tex@2krueger.de>
Date: Sun, 25 Apr 2021 17:11:36 +0200
Subject: [PATCH] TeX interface to retrieve handle for MML

---
 luamml-amsmath.lua |  2 --
 luamml-tex.lua     | 15 ++++++++++++++-
 luamml.sty         |  2 +-
 test_tex.tex       |  7 +++++++
 4 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/luamml-amsmath.lua b/luamml-amsmath.lua
index 0ca5d02..f25ca05 100644
--- a/luamml-amsmath.lua
+++ b/luamml-amsmath.lua
@@ -24,7 +24,6 @@ lua.get_functions_table()[funcid] = function()
     mml = {[0] = 'mtd', mml}
   end
   local row_temp = tex.nest[tex.nest.ptr-1]
-  print(row_temp)
   props = properties[row_temp]
   if not props then
     props = {}
@@ -42,7 +41,6 @@ token.set_lua('luamml_amsmath_finalize_row:', funcid, 'protected')
 lua.get_functions_table()[funcid] = function()
   -- TODO: Error handling etc
   local row_temp = tex.nest[tex.nest.ptr-1]
-  print("final", row_temp)
   local props = properties[row_temp]
   if not props then return end
   if not props.mathml_row then return end
diff --git a/luamml-tex.lua b/luamml-tex.lua
index ad9c176..28e0c3e 100644
--- a/luamml-tex.lua
+++ b/luamml-tex.lua
@@ -36,6 +36,7 @@ end
 --    Bit 2: Integrate with table mechanism
 
 local mlist_buffer
+local mlist_result
 
 luatexbase.add_to_callback('pre_mlist_to_hlist_filter', function(mlist, style)
   local flag = tex.count.l__luamml_flag_int
@@ -56,7 +57,7 @@ luatexbase.add_to_callback('pre_mlist_to_hlist_filter', function(mlist, style)
   end
   local xml = process_mlist(new_mlist, style == 'display' and 0 or 2)
   if flag & 2 == 0 then
-    print(write_xml(make_root(xml, (style == 'display' or flag & 1 == 1) and 0 or 2)) .. '\n')
+    mlist_result = write_xml(make_root(xml, (style == 'display' or flag & 1 == 1) and 0 or 2))
   else
     assert(style == 'text')
     local startmath = tex.nest.top.tail
@@ -73,3 +74,15 @@ luatexbase.add_to_callback('pre_mlist_to_hlist_filter', function(mlist, style)
   end
   return true
 end, 'dump_list')
+
+funcid = luatexbase.new_luafunction'luamml_get_last_mathml_stream:e'
+token.set_lua('luamml_get_last_mathml_stream:e', funcid)
+lua.get_functions_table()[funcid] = function()
+  if not mlist_result then
+    tex.error('No current MathML data', {
+        "I was asked to provide MathML code for the last formula, but there weren't any new formulas since you last asked."
+      })
+  end
+  tex.sprint(-2, tostring(pdf.immediateobj('stream', mlist_result, '/Subtype /application#2Fmathml+xml\n' .. token.scan_argument(true))))
+  mlist_result = nil
+end
diff --git a/luamml.sty b/luamml.sty
index f95c505..89dc1e5 100644
--- a/luamml.sty
+++ b/luamml.sty
@@ -14,4 +14,4 @@
   \int_set:Nn \l__luamml_flag_int { 6 }
 }
 
-\RequirePackage { luamml-patches-amsmath }
+% \RequirePackage { luamml-patches-amsmath }
diff --git a/test_tex.tex b/test_tex.tex
index 6fd13bb..fb1e967 100644
--- a/test_tex.tex
+++ b/test_tex.tex
@@ -4,10 +4,17 @@
 \usepackage{luamml}
 \RegisterFamilyMapping\symsymbols{oms}
 \RegisterFamilyMapping\symletters{oml}
+\ExplSyntaxOn
+\pdfvariable compresslevel0
+\cs_new_protected:Npn \ShowMathMLObj {
+  \message { \luamml_get_last_mathml_stream:e{}~0~R }
+}
+\ExplSyntaxOff
 \begin{document}
 \[
   ax^2+bx+c=0
 \]
+\ShowMathMLObj
 \[
   x = \frac{-b \pm \sqrt{b^2-4ac}}{2a}.
 \]