Safe Haskell | None |
---|---|
Language | Haskell2010 |
Documentation
newtype Fail m a where Source #
An effect corresponding to the MonadFail
type class.
Effly'
s MonadFail
instance is based
on this effect; by having access to Fail
, you're able to invoke
handle pattern-match failure automatically inside of effect handlers.
Each Fail
interpreter's associated carrier
has an MonadFail
instance based on
how it interprets Fail
. This means you can use
an Fail
interpreter to locally gain access to an MonadFail
instance inside of application code.