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

Contents

Specialised combinators
Bifunctor
Bitraversable
Associativity and commutativity
Other operations
preview
toListOf
is / has
over / map

Synopsis

value bimapThese
value mapHere
value mapThere
value bitraverseThese
value swapThese
value assocThese
value unassocThese
value justThis
value justThat
value justThese
value justHere
value justThere
value catThis
value catThat
value catThese
value catHere
value catThere
value isThis
value isThat
value isThese
value hasHere
value hasThere
value mapThis
value mapThat
value mapThese

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

Specialised combinators

Bifunctor

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

Source#

Bifunctor bimap.

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

Source#

mapHere = Control.Lens.over here

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

Source#

mapThere = Control.Lens.over there

Bitraversable

valuebitraverseThese

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

Source#

Bitraversable bitraverse.

Associativity and commutativity

valueswapThese :: These a b -> These b a

Source#

These is commutative.

swapThese . swapThese = id

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

Source#

These is associative.

assocThese . unassocThese = id
unassocThese . assocThese = id

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

Source#

These is associative. See assocThese.

Other operations

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

Source#

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

Source#

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]

Source#

Select all This constructors from a list.

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

Source#

Select all That constructors from a list.

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

Source#

Select all These constructors from a list.

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

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

is / has

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