Modulethese-1.2.1Haskell2010

Data.These.Combinators

This module provides

specialised versions of class members e.g. bitraverseThese
non-lens variants of Data.These.Lens things, e.g justHere

25 values

Packagethese-1.2.1
Exports25
LanguageHaskell2010
LicenceBSD-3-Clause
SourceCombinators.hs

Specialised combinators

0 declarations

Bifunctor

valuebimapThese :: (a -> c) -> (b -> d) -> These a b -> These c d

Bifunctor bimap.

valuemapHere :: (a -> c) -> These a b -> These c b

mapHere = Control.Lens.over here

valuemapThere :: (b -> d) -> These a b -> These a d

mapThere = Control.Lens.over there

Bitraversable

valuebitraverseThese

:: Applicative f
=> a -> f c
-> b -> f d
-> These a b
-> f (These c d)

Bitraversable bitraverse.

Associativity and commutativity

valueswapThese :: These a b -> These b a

These is commutative.

swapThese . swapThese = id

valueassocThese :: These (These a b) c -> These a (These b c)

These is associative.

assocThese . unassocThese = id
unassocThese . assocThese = id

valueunassocThese :: These a (These b c) -> These (These a b) c

These is associative. See assocThese.

Other operations

0 declarations

preview

justThis  = Control.Lens.preview _This
justThat  = Control.Lens.preview _That
justThese = Control.Lens.preview _These
justHere  = Control.Lens.preview here
justThere = Control.Lens.preview there

valuejustThis :: These a b -> Maybe a

valuejustThat :: These a b -> Maybe b

valuejustThese :: These a b -> Maybe (a, b)

valuejustHere :: These a b -> Maybe a

Example1 expression

>>> justHere (This 'x')Just 'x'

Example1 expression

>>> justHere (That 'y')Nothing

Example1 expression

>>> justHere (These 'x' 'y')Just 'x'

valuejustThere :: These a b -> Maybe b

Example1 expression

>>> justThere (This 'x')Nothing

Example1 expression

>>> justThere (That 'y')Just 'y'

Example1 expression

>>> justThere (These 'x' 'y')Just 'y'

toListOf

catThis  = Control.Lens.toListOf (Control.Lens.folded . _This)
catThat  = Control.Lens.toListOf (Control.Lens.folded . _That)
catThese = Control.Lens.toListOf (Control.Lens.folded . _These)
catHere  = Control.Lens.toListOf (Control.Lens.folded . here)
catThere = Control.Lens.toListOf (Control.Lens.folded . there)

valuecatThis :: [These a b] -> [a]

Select all This constructors from a list.

valuecatThat :: [These a b] -> [b]

Select all That constructors from a list.

valuecatThese :: [These a b] -> [(a, b)]

Select all These constructors from a list.

valuecatHere :: [These a b] -> [a]

valuecatThere :: [These a b] -> [b]

is / has

5 declarations

isThis   = Control.Lens.Extra.is _This
isThat   = Control.Lens.Extra.is _That
isThese  = Control.Lens.Extra.is _These
hasHere  = Control.Lens.has here
hasThere = Control.Lens.has there

valueisThis :: These a b -> Bool

isThis = isJust . justThis

valueisThat :: These a b -> Bool

isThat = isJust . justThat

valueisThese :: These a b -> Bool

isThese = isJust . justThese

valuehasHere :: These a b -> Bool

hasHere = isJust . justHere

valuehasThere :: These a b -> Bool

hasThere = isJust . justThere

over / map

3 declarations

valuemapThis :: (a -> a) -> These a b -> These a b

valuemapThat :: (b -> b) -> These a b -> These a b

valuemapThese :: ((a, b) -> (a, b)) -> These a b -> These a b