strict-0.1: Strict data typesContentsIndex
Data.Strict.Maybe
Portabilityportable
Stabilityexperimental
MaintainerRoman Leshchinskiy <rl@cse.unsw.edu.au>
Description

Strict Maybe.

Same as the standard Haskell Maybe, but Just _|_ = _|_

Note that strict Maybe is not a monad since return _|_ >>= f = _|_ which is not necessarily the same as f _|_.

Synopsis
data Maybe a
= Nothing
| Just !a
isJust :: Maybe a -> Bool
isNothing :: Maybe a -> Bool
fromJust :: Maybe a -> a
fromMaybe :: a -> Maybe a -> a
maybe :: b -> (a -> b) -> Maybe a -> b
Documentation
data Maybe a
The type of strict optional values.
Constructors
Nothing
Just !a
show/hide Instances
Functor Maybe
Eq a => Eq (Maybe a)
Ord a => Ord (Maybe a)
Read a => Read (Maybe a)
Show a => Show (Maybe a)
isJust :: Maybe a -> Bool
Yields True iff the argument is of the form Just _.
isNothing :: Maybe a -> Bool
Yields True iff the argument is Nothing.
fromJust :: Maybe a -> a
Extracts the element out of a Just and throws an error if the argument is Nothing.
fromMaybe :: a -> Maybe a -> a
Given a default value and a Maybe, yield the default value if the Maybe argument is Nothing and extract the value out of the Just otherwise.
maybe :: b -> (a -> b) -> Maybe a -> b
Given a default value, a function and a Maybe value, yields the default value if the Maybe value is Nothing and applies the function to the value stored in the Just otherwise.
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