| Safe Haskell | None |
|---|---|
| Language | Haskell2010 |
Control.Effect.Reader
Contents
- class MemberEffect Reader (Reader r) l => EffectReader r l
- data Reader r a
- runReader :: r -> Effect (Reader r :+ l) a -> Effect l a
- ask :: EffectReader r l => Effect l r
- asks :: EffectReader r l => (r -> a) -> Effect l a
- local :: EffectReader r l => (r -> r) -> Effect l a -> Effect l a
- stateReader :: EffectState s l => Effect (Reader s :+ l) a -> Effect l a
Documentation
class MemberEffect Reader (Reader r) l => EffectReader r l Source #
Instances
| MemberEffect (* -> * -> *) Reader (Reader r) l => EffectReader r l Source # | |
An effect that provides an implicit environment.
runReader :: r -> Effect (Reader r :+ l) a -> Effect l a Source #
Completely handles a Reader effect by providing an
environment value to be used throughout the computation.
ask :: EffectReader r l => Effect l r Source #
Retrieves the current environment.
asks :: EffectReader r l => (r -> a) -> Effect l a Source #
Retrieves a value that is a function of the current environment.
local :: EffectReader r l => (r -> r) -> Effect l a -> Effect l a Source #
Runs a computation with a modified environment.
stateReader :: EffectState s l => Effect (Reader s :+ l) a -> Effect l a Source #
Executes a reader computation which obtains its environment value from a state effect.