[Haskell-cafe] Re: not possible with monad transformers ?
Marcin 'Qrczak' Kowalczyk
qrczak at knm.org.pl
Tue Nov 30 19:37:16 EST 2004
Ben Rudiak-Gould <Benjamin.Rudiak-Gould at cl.cam.ac.uk> writes:
> I may be confused, but I don't think it does. It seems like the OP
> wants a type like
> data Perhaps a = Success a | Failure [Error]
When writing a compiler, it makes sense to collect errors as by the
writer monad, and not abort anything - producing dummy values instead
(except perhaps some fatal errors when it's inconvenient).
__("< Marcin Kowalczyk
\__/ qrczak at knm.org.pl
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