[luatex] node.traverse

[Herbert Voss]

Hi all,

am I right that I cannot use node.traverse_id for node _trees_
like the following one?

\directlua{function checknode(head)
for t in node.traverse(head) do
  if t.id==0 or t.id==1 then checknode(t.list) end
  if t.id==37 then
   if t.char>96 and t.char<122 then t.char=t.char-32 end
  end
end
return true
end
callback.register("post_linebreak_filter",checknode)}

abc2112\par And so on \dots %% converting into uppercase

\bye

traverse and traverse_id work only on lists, right?

And next question: should one use t.head instead of t.list.
I read that the name list changes to head, but I can't find
the documentation where I read it.

Herbert