Hello,

How does one deal cleanly with implementation differences, e.g. things like isAscii being defined in Hugs but not in GHC? I'd hate to resort to Makefile trickery and preprocessing.

You can try to use some special compatibility module where you collect all the workarounds for the implmentation differences. But in this particular you should better read the (library) report and simply import the Char module (from where isAscii should be exported -- Hugs still exports it from the Prelude though it shouldn't). Wolfgang -- Wolfgang Lux Phone: +49-251-83-38263 Institut fuer Wirtschaftinformatik FAX: +49-251-83-38259 Universitaet Muenster Email: wlux@uni-muenster.de