Thomas A. Schmitz wrote:
Hi all,
I'm working on my Greek module again and am trying to filter and massage
the input via lpeg, but there's something I don't quite get. As a
minimal example: suppose I want to substitute A and B in my input with X
and leave all other letters alone. Here's my attempt:
brrr ... massaging input ... can be dangerous ... anyhow, here you go
\startluacode
local replace = {
A = "X",
B = "X",
}
setmetatable(replace, { __index = function(t,k)
return k
end })
local dosub = (lpeg.Cs(1)) / replace
local subs =
(dosub)^0
function test (string)
tex.sprint(lpeg.match(subs,string))
end
\stopluacode
\def\Substitute#1{\ctxlua{test("#1")}}
\starttext
\Substitute{thomas ABC whatever}
\stoptext
and yes, it's slow; the next variant is faster but takes a bit more
memory (neglectable compared to what is alrwady taken)
setmetatable(replace, { __index = function(t,k)
t[k] = k
return k
end })
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