Hi all,
While trying to do some right-to-left math experimentation (with very
good results so far[1]) I tried writing some lua code that takes care of
keeping numbers left-to-right by inserting TLT dir nodes around them.
I just found that when node.insert_before() is executed on the very
first node in an hlist no nodes get inserted, I'm not sure if this is a
bug, feature or some dumb thing in the code I wrote. Tested with luatex
0.70.1 and 0.67.0.
See the attached files.
[1]
http://tex.stackexchange.com/questions/20666/typesetting-right-to-left-math/21082#21082
BTW, I noticed that \textdir and \mathdir has no effect inside math
formulas, is there any other way to override the global math direction
(apart from fiddling with lua.)
Regards,
Khaled
--
Khaled Hosny
Egyptian
Arab
\tracingoutput=1
\tracingonline=1
\showboxdepth=\maxdimen
\showboxbreadth=\maxdimen
\directlua{dofile("m.lua")}
\mathdir TRT
$$
{123} \quad {456} \quad 789
$$
\bye
rtlmath = {}
local glyph = node.id("glyph")
local hlist = node.id("hlist")
local vlist = node.id("vlist")
local function isnumber(n)
local c = n.char
if c <= 0x39 and c >= 0x30 then
return true
else
return false
end
end
local function newdir(dir)
local n = node.new("whatsit","dir")
n.dir = dir
return n
end
local function donumbers(head)
local start = false
for n in node.traverse(head) do
if n.id == glyph then
if isnumber(n) then
if start then
if n.next and n.next.id == glyph and isnumber(n.next) then
else
node.insert_after(head, n, newdir("-TLT"))
start = false
end
else
if n.next and n.next.id == glyph and isnumber(n.next) then
node.insert_before(head, n, newdir("+TLT"))
start = true
else
end
end
end
else
if start then
node.insert_after(head, n, newdir("-TLT"))
start = false
end
if n.id == hlist or n.id == vlist then
donumbers(n.list)
end
end
end
return head
end
rtlmath.numbers = donumbers
--nodes.tasks.appendaction("math", "after", "rtlmath.numbers")
callback.register("mlist_to_hlist",
function(h, s, b)
h = node.mlist_to_hlist(h, s, b)
h = donumbers(h)
return h
end
)
