luatex examples - Traversing TeX nodes

[Piotr Kopszak <kopszak@gmail.com>]

Hello,

I am trying to compile luatex examples from http://luatex.bluwiki.com
. How could I make it work with ConTeXt? The following fails.
-----------------------------------------------------------------------------------------------------------------------------------
\directlua0{
 local glyph = node.id('glyph')
 local hlist = node.id('hlist')
 local vlist = node.id('vlist')

 function gothru(h,prof)
   for t in node.traverse(h) do
     texio.write_nl(string.rep("...",prof) .. 'NODE type=' ..
node.type(t.id) .. ' subtype=' .. t.subtype )
     if t.id == hlist or t.id == vlist then
       texio.write(' w=' .. t.width .. ' h=' .. t.height .. ' d=' ..
t.depth .. ' s=' .. t.shift )
	   gothru(t.list,prof+1)
     end
     if t.id == glyph then
       texio.write(' font=' .. t.font .. ' char=' .. t.char .. '
width=' font.fonts[t.font].characters[t.char]['width'])
     end
   end
 end

 callback.register('pre_linebreak_filter',
   function(h)
      gothru(h,0)
      return true
   end
   )
}

\starttext
bla bla bla bla
\stoptext
-------------------------------------------------------------------------------------------------------

best

Piotr

-- 
http://okle.pl
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