On 3/15/2022 6:16 PM, Javier Bezos wrote:
How can I process every single letter in math? Processing
glyph nodes in text is more or less trivial, and to some
extent even in-line math (surrounded by 'math' type nodes),
but processing math, including displays, sub/superscripts,
fractions, radicals. etc.? From the manual I think the
solution must be the node.mlist_to_hlist and the
corresponding callback, and this is what I’ve achieved
so far:
-----------------------
\directlua{
function math_tweak(head, d, p)
head = node.mlist_to_hlist(head, d, p)
for item in node.traverse(head) do
if item.id == node.id'glyph' then
item.char = 88
end
end
return head, d, p
end
callback.register('mlist_to_hlist', math_tweak)
}
$a$ ${b\over c}$ $\sqrt{d}$ $e$
$$f$$
\bye
------------------------
Here, only ‘a’, ‘e’ and ‘f’ are converted to ‘X’ (= 88).
With a branch for item.id == 0 calling recursively the
function sub/superscripts are processed, but that’s not
quite correct.
just print(item.id) and you'll probably see vlists as well so you need
to also process item.id == 1; you might also run into composed shapes
(extensibles) .. it also depends onm what a macro package does (\frac,
\sqrt which is not standardized and therefore less predictable)
Hans
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