function that purges 8 bit text?

[Henning Hraban Ramm <hraban@fiee.net>]

Hi there!

I try to typeset a roleplaying character sheet as PDF form;
it contains a table of skills, each line is a \SkillField after this 
def:

\def\SkillField#1#2{\bTR\bTD #1\hfill (#2) \eTD \bTD 
\definefield[#1][line][SkillSetup][#2]\field[#3]\eTD\eTR}
e.g.
\SkillField{Climbing}{+8}

becomes a table line like:

Climbing   (+8)  [+8]

Now there are a lot of skills that contain e.g. umlauts, so that 
\definefield[#1] fails.
I don't like to introduce a third parameter.

Is there a possibility to strip all invalid chars from a string, so that
\SkillField{Erzählen}{0} can define a field named "Erzaehlen" or 
"Erzhlen" or "Erzahlen"?
(Sorry, I can't program in TeX.)

If this is not possible, I'll try an optional parameter.

Grüßlis vom Hraban!
---
http://www.fiee.net/texnique/
http://contextgarden.net