Hi David,
Here is a better example. Instead of directlua, we register a function
and call that one. The funny expandafters make sure we call them
out-of-order. It works ok in luatex-plain. In fact, \directlua itself
could be reimplemented as function but it is slightly slower then so we
keep it as core primitive.
(Btw, some day soon I'm going to see if some backend primitives can be
replaced by directlua + tokenscanner calls). The smaller the core and
the more decoupled the backend is from the scanner, the better.)
\directlua{
gadgets = gadgets or { } % reserved namespace
gadgets.functions = { }
local registered = { }
function gadgets.functions.reserve()
local numb = newtoken.scan_int()
local name = newtoken.scan_string()
local okay = string.gsub(name,"[\string\\ ]","")
registered[okay] = numb
texio.write_nl("reserving lua function '"..okay.."' with number
"..numb)
end
function gadgets.functions.register(name,f)
local okay = string.gsub(name,"[\string\\ ]","")
local numb = registered[okay]
if numb then
texio.write_nl("registering lua function '"..okay.."' with
number "..numb)
lua.get_functions_table()[numb] = f
else
texio.write_nl("lua function '"..okay.."' is not reserved")
end
end
}
\newcount\lastallocatedluafunction
\def\newluafunction#1%
{\ifdefined#1\else
\global\advance\lastallocatedluafunction 1
\global\chardef#1\lastallocatedluafunction
\directlua{gadgets.functions.reserve()}#1{\detokenize{#1}}%
\fi}
\newluafunction\UcharcatLuaOne
\newluafunction\UcharcatLuaTwo
\directlua {
local cct = nil
local chr = nil
gadgets.functions.register("UcharcatLuaOne",function()
chr = newtoken.scan_int()
cct = tex.getcatcode(chr)
tex.setcatcode(chr,newtoken.scan_int())
tex.sprint(unicode.utf8.char(chr))
end)
gadgets.functions.register("UcharcatLuaTwo",function()
tex.setcatcode(chr,cct)
end)
}
\def\Ucharcat
{\expandafter\expandafter\expandafter\luafunction
\expandafter\expandafter\expandafter\UcharcatLuaTwo
\luafunction\UcharcatLuaOne}
A:\the\catcode65:\Ucharcat 65 11:A:\the\catcode65\par
A:\the\catcode65:\Ucharcat 65 5:A:\the\catcode65\par
A:\the\catcode65:\Ucharcat 65 11:A:\the\catcode65\par
Hans
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