From: Hans Hagen <pragma@wxs.nl>
To: mailing list for ConTeXt users <ntg-context@ntg.nl>
Subject: Re: lpeg substitution
Date: Tue, 11 Aug 2009 12:59:02 +0200 [thread overview]
Message-ID: <4A814EF6.60101@wxs.nl> (raw)
In-Reply-To: <00765789-37D5-4318-9055-898AAA792135@uni-bonn.de>
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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Hans Hagen | PRAGMA ADE
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next prev parent reply other threads:[~2009-08-11 10:59 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-08-11 9:34 Thomas A. Schmitz
2009-08-11 10:59 ` Hans Hagen [this message]
2009-08-11 11:21 ` Thomas A. Schmitz
2009-08-11 12:35 ` Hans Hagen
2009-08-11 15:14 ` Thomas A. Schmitz
2009-08-11 22:01 ` Hans Hagen
2009-08-12 6:51 ` Taco Hoekwater
2009-08-12 8:32 ` Hans Hagen
2009-08-12 9:04 ` Thomas A. Schmitz
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