[NTG-context] lpeg substitution

11 Aug 2009

      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:

\startluacode
do
     local replace = {
         A = "X",
         B = "X",
     }

     local dosub = (lpeg.Cs(1)) / replace

     local subs =
         (dosub)^0

     function test (string)
	tex.sprint(lpeg.match(subs,string))
     end
end
\stopluacode

\def\Substitute#1{\ctxlua{test("#1")}}

\starttext

\Substitute{ABC}

\stoptext

It substitutes alright, but the "C" is not included in the stream  
which ctxlua gives to TeX. How can I modify my lpeg pattern?

Thanks, and all best

Thomas

[NTG-context] lpeg substitution

Thomas A. Schmitz