[Hat] Oddness...

[Malcolm Wallace]

Thomas Davie <tom.davie at gmail.com> writes:

> I've been trying to get hat-trans to eat QuickCheck, without much  
> success.  Is there something I'm missing?  I'm getting this error:
> 
> hat-trans QuickCheck.hs
> hat-trans: Variable or constructor not in scope: chr

The QuickCheck.hs module available from John Hughes' webpage was
written for an older version of Hugs which wasn't compliant with
Haskell'98.  The 'chr' function is exported from the standard Char
library.

However, I have to wonder whether it makes any sense to trace
QuickCheck itself?  In the AFP summer school 2002, the students used
QC to find a failure, then fed only that failing case into Hat to
discover its cause.

For delta-debugging, I expect you would want both a failing case and
a passing case, but I don't suppose you really want to bother with
tracing all the QC machinery that found them for you.

Regards,
    Malcolm