[Haskell-cafe] Do we need Monad fail (or MonadFail)?
voldermort at hotmail.com
Tue Dec 21 10:49:48 CET 2010
Monads seem to use fail in one of three ways:
-Regular monads leave it at the default definition of error
-MonadPlus sometimes redefines it to mzero
-IO redefines it to failIO
Are there any other definitions of fail? If not, does the special case of IO really need a class-level definition, or
could there be another way of dealing with failed pattern matches?
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