Initial

mlist_to_mml.lua

@@ -0,0 +1,172 @@
+local noad_t, accent_t, style_t, choice_t = node.id'noad', node.id'accent', node.id'style', node.id'choice'
+local radical_t, fraction_t, fence_t = node.id'radical', node.id'fraction', node.id'fence'
+
+local math_char_t, sub_box_t, sub_mlist_t = node.id'math_char', node.id'sub_box', node.id'sub_mlist'
+
+local noad_sub = node.subtypes'noad'
+local radical_sub = node.subtypes'radical'
+local fence_sub = node.subtypes'fence'
+
+local nodes_to_table
+
+-- We ignore large_... since they aren't used for modern fonts
+local function delim_to_table(delim)
+  if not delim then return end
+  local fam = delim.small_fam
+  return {[0] = 'mo', utf8.char(delim.small_char), ['tex:family'] = fam ~= 0 and fam or nil }
+end
+
+local function kernel_to_table(kernel)
+  if not kernel then return end
+  local id = kernel.id
+  if id == math_char_t then
+    local char = kernel.char
+    local elem = char >= 0x30 and char < 0x39 and 'mn' or 'mi'
+    local fam = kernel.fam
+    return {[0] = elem, utf8.char(kernel.char), ['tex:family'] = fam ~= 0 and fam or nil }
+  elseif id == sub_box_t then
+    return {[0] = 'mi', {[0] = 'mglyph', ['tex:box'] = kernel.list}}
+  elseif id == sub_mlist_t then
+    return nodes_to_table(kernel.list)
+  else
+    error'confusion'
+  end
+end
+
+local function do_sub_sup(t, n)
+  sub = kernel_to_table(n.sub)
+  sup = kernel_to_table(n.sup)
+  if sub then
+    if sup then
+      return {[0] = 'msubsup', t, sub, sup}
+    else
+      return {[0] = 'msub', t, sub}
+    end
+  elseif sup then
+    return {[0] = 'msup', t, sup}
+  else
+    return t
+  end
+end
+
+local function noad_to_table(noad, sub)
+  local class = noad_sub[sub]
+  local nucleus = kernel_to_table(noad.nucleus)
+  if class == 'ord' then
+  -- elseif class == 'opdisplaylimits' then
+  -- elseif class == 'oplimits' then
+  -- elseif class == 'opnolimits' then
+  elseif class == 'bin' or class == 'rel' or class == 'open'
+      or class == 'close' or class == 'punct' or class == 'inner' then
+    if nucleus[0] == 'mrow' then
+      -- TODO
+    else
+      nucleus[0] = 'mo'
+    end
+    nucleus['tex:class'] = class
+  -- elseif class == 'under' then
+  -- elseif class == 'over' then
+  -- elseif class == 'vcenter' then
+  else
+  --   error[[confusion]]
+    nucleus['tex:TODO'] = class
+  end
+  return do_sub_sup(nucleus, noad)
+end
+
+local function radical_to_table(radical, sub)
+  local kind = radical_sub[sub]
+  local nucleus = kernel_to_table(radical.nucleus)
+  local left = delim_to_table(radical.left)
+  local elem
+  if kind == 'radical' or kind == 'uradical' then
+    -- FIXME: Check that this is really a square root
+    elem = {[0] = 'msqrt', nucleus}
+  elseif kind == 'uroot' then
+    -- FIXME: Check that this is really a root
+    elem = {[0] = 'msqrt', nucleus, delim_to_table(radical.degree)}
+  elseif kind == 'uunderdelimiter' then
+    elem = {[0] = 'munder', left, nucleus}
+  elseif kind == 'uoverdelimiter' then
+    elem = {[0] = 'mover', left, nucleus}
+  elseif kind == 'udelimiterunder' then
+    elem = {[0] = 'munder', nucleus, left}
+  elseif kind == 'udelimiterover' then
+    elem = {[0] = 'mover', nucleus, left}
+  else
+    error[[confusion]]
+  end
+  return do_sub_sup(elem, radical)
+end
+
+local function fraction_to_table(fraction, sub)
+  local num = kernel_to_table(fraction.num)
+  local denom = kernel_to_table(fraction.denom)
+  local left = delim_to_table(fraction.left)
+  -- local middle = delim_to_table(fraction.middle)
+  local right = delim_to_table(fraction.right)
+  local mfrac = {[0] = 'mfrac',
+    linethickness = fraction.width and fraction.width == 0 and 0 or nil,
+    bevelled = fraction.middle and "true" or nil,
+    num,
+    denom,
+  }
+  if left then
+    return {[0] = 'mrow',
+      left,
+      mfrac,
+      right, -- might be nil
+    }
+  elseif right then
+    return {[0] = 'mrow',
+      mfrac,
+      right,
+    }
+  else
+    return mfrac
+  end
+end
+
+local function fence_to_table(fraction, sub)
+  error[[TODO]]
+  return {
+    kind = fence_sub[sub],
+  }
+end
+
+function nodes_to_table(head)
+  local t = {[0] = "mrow"}
+  for n, id, sub in node.traverse(head) do
+    if id == noad_t then
+      t[#t+1] = noad_to_table(n, sub)
+    elseif id == accent_t then
+      print(n)
+      t[#t+1] = {[0] = 'TODO', accent = n}
+    elseif id == style_t then
+      print(n)
+      t[#t+1] = {[0] = 'TODO', style = n}
+    elseif id == choice_t then
+      print(n)
+      t[#t+1] = {[0] = 'TODO', choice = n}
+    elseif id == radical_t then
+      t[#t+1] = radical_to_table(n, sub)
+    elseif id == fraction_t then
+      t[#t+1] = fraction_to_table(n, sub)
+    elseif id == fence_t then
+      print(n)
+      t[#t+1] = {[0] = 'TODO', fence = n}
+    else
+      print(n)
+      t[#t+1] = n
+    end
+  end
+  return t
+end
+
+return function(head)
+  local result = nodes_to_table(head)
+  result[0] = 'math'
+  result.xmlns = 'http://www.w3.org/1998/Math/MathML'
+  result['xmlns:tex'] = 'http://typesetting.eu/2021/LuaMathML'
+  return result
+end

test_tex.lua

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+local inspect = require'inspect'
+local function show(t) return print(inspect(t)) end
+
+local mlist_to_table = require'mlist_to_mml'
+local write_xml = require'write_xml'
+
+luatexbase.add_to_callback('pre_mlist_to_hlist_filter', function(mlist)
+  print'\n\n'
+  local xml = mlist_to_table(mlist)
+  show(write_xml(xml))
+  print'\n'
+  return true
+end, 'dump_list')

test_tex.tex

@@ -0,0 +1,14 @@
+\documentclass{article}
+\usepackage{unicode-math}
+\directlua{require'test_tex'}
+\begin{document}
+\[
+  ax^2+b+c=0
+\]
+\[
+  x = \frac{-b \pm \sqrt{b^2-4ac}}{2a}.
+\]
+\[
+  x = \longdivision{5}
+\]
+\end{document}

test_xml.lua

@@ -0,0 +1,16 @@
+local write_xml = require'write_xml'
+
+print(write_xml{[0] = "math", xmlns = "http://www.w3.org/1998/Math/MathML",
+    {[0] = "mi", "a"},
+    {[0] = "msup",
+      {[0] = "mi", "x"},
+      {[0] = "mn", "2"},
+    },
+    {[0] = "mo", "+"},
+    {[0] = "mi", "b"},
+    {[0] = "mi", "x"},
+    {[0] = "mo", "+"},
+    {[0] = "mi", "c"},
+    {[0] = "mo", "="},
+    {[0] = "mn", "0"},
+  })

write_xml.lua

@@ -0,0 +1,38 @@
+-- FIXME: Not sure yet if this will be needed
+local function escape_name(name)
+  return name
+end
+
+-- FIXME: Not sure yet if this will be needed
+local escapes = {
+  ['"'] = """,
+  ['<'] = "&lt;",
+  ['>'] = "&gt;",
+  ['&'] = "&amp;",
+}
+local function escape_text(text)
+  return text:gsub('("<>&)', escapes)
+end
+
+local function write_elem(tree)
+  if not tree[0] then print('ERR', require'inspect'(tree)) end
+  local escaped_name = escape_name(assert(tree[0]))
+  local out = "<" .. escaped_name
+  for attr, val in next, tree do if type(attr) == 'string' then
+    out = out .. ' ' .. escape_name(attr) .. '="' .. escape_text(val) .. '"'
+  end end
+  if not tree[1] then
+    return out .. '/>'
+  end
+  out = out .. '>'
+  for _, elem in ipairs(tree) do
+    if type(elem) == 'string' then
+      out = out .. escape_text(elem)
+    else
+      out = out .. write_elem(elem)
+    end
+  end
+  return out .. '</' .. escaped_name .. '>'
+end
+
+return write_elem