Module

Data.These

#These 

data These a b

Data type isomorphic to α ∨ β ∨ (α ∧ β) or Either a (Either b (Tuple a b)).

Constructors

Instances

#these 

these :: forall a b c. (a -> c) -> (b -> c) -> (a -> b -> c) -> These a b -> c

Given functions to handle each constructor, collapse a These value into single value.

#thisOrBoth 

thisOrBoth :: forall a b. a -> Maybe b -> These a b

#thatOrBoth 

thatOrBoth :: forall a b. b -> Maybe a -> These a b

#maybeThese 

maybeThese :: forall a b. Maybe a -> Maybe b -> Maybe (These a b)

Takes a pair of Maybes and attempts to create a These from them.

#fromThese 

fromThese :: forall a b. a -> b -> These a b -> Tuple a b

Takes two default values and a These value. If the These value is This or That, the value wrapped in the These value and its corresponding default value are wrapped into a Tuple. Otherwise, the values stored in the Both are rewrapped into a Tuple.

#theseLeft 

theseLeft :: forall a b. These a b -> Maybe a

Returns an a value if possible.

#theseRight 

theseRight :: forall a b. These a b -> Maybe b

Returns a b value if possible.

#this 

this :: forall a b. These a b -> Maybe a

Returns the a value if and only if the value is constructed with This.

#that 

that :: forall a b. These a b -> Maybe b

Returns the b value if and only if the value is constructed with That.

#both 

both :: forall a b. These a b -> Maybe (Tuple a b)

Returns the a and b values if and only if they are constructed with Both.

#isThis 

isThis :: forall a b. These a b -> Boolean

Returns true when the These value is This

#isThat 

isThat :: forall a b. These a b -> Boolean

Returns true when the These value is That

#isBoth 

isBoth :: forall a b. These a b -> Boolean

Returns true when the These value is Both

#swap 

swap :: forall a b. These a b -> These b a

Swap between This and That, and flips the order for Both.

#assoc 

assoc :: forall a b c. These (These a b) c -> These a (These b c)

Re-associate These from left to right.

Modules