[Haskell-cafe] Use of the Try typeclass

Edward Z. Yang ezyang at MIT.EDU
Thu Dec 31 00:11:34 EST 2009

Excerpts from Alexander Dunlap's message of Thu Dec 31 00:06:58 -0500 2009:
> Why are you importing both Control.Failure and Control.Monad.Failure
> when the latter just re-exports the former? Are you using the latest
> versions of the two packages? Try importing just
> Control.Monad.Failure.MTL; that provides the MTL failure instances and
> also re-exports Control.Failure.

That's correct. I imported both when Control.Monad.Failure.MTL failed
to expose try:

ezyang at javelin:~/Dev/wizard$ ghci
Prelude> :m +Control.Monad.Failure.MTL
Prelude Control.Monad.Failure.MTL> :t try

<interactive>:1:0: Not in scope: `try'

Which, doesn't really seem like it should be the case.


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