| Safe Haskell | Safe-Inferred |
|---|---|
| Language | Haskell2010 |
Control.RichConditional
- class TotalIf a b c where
- decide :: a -> Decision b c
- class PartialIf a b where
- indicate :: a -> Indication b
- ifElse :: TotalIf a b c => a -> (b -> d) -> (c -> d) -> d
- inCase :: PartialIf a b => a -> (b -> c) -> c -> c
- ensure :: (Monad m, MonadPlus m, PartialIf a b) => a -> m b
- ensurePositive :: forall m a b c u. (Monad m, MonadPlus m, TotalIf a b c) => a -> u c -> m b
- ensureNegative :: forall m a b c u. (Monad m, MonadPlus m, TotalIf a b c) => a -> u b -> m c
Documentation
class TotalIf a b c where Source
Instances of this class provide a test on some type a with an alternative case for when it fails. If it passes, it gives a value of type b; otherwise, it gives a value of type c.
class PartialIf a b where Source
Instances of this class provide a test on some type a. If it passes, it gives a value of type b; otherwise, it gives Nothing.
ifElse :: TotalIf a b c => a -> (b -> d) -> (c -> d) -> d Source
A conditional using a TotalIf instance. This is just like the
function either which decomposes an Either, except that the Either
is produced through a TotalIf instance determined by the types of
the cases.
inCase :: PartialIf a b => a -> (b -> c) -> c -> c Source
A conditional using a PartialIf instance. This is just like the
function maybe which decomposes a Maybe, except that the Maybe
is produced through an PartialIf instance determined by the type of
the positive case.
ensure :: (Monad m, MonadPlus m, PartialIf a b) => a -> m b Source
Like guard but with a bonus: if the condition passes, you actually get
a hold of some new information.