40 lines
968 B
Idris
40 lines
968 B
Idris
|
module Control.Lens.OptionalFold
|
||
|
|
|
||
|
|
import Data.Profunctor
|
||
|
|
import Data.Profunctor.Costrong
|
||
|
|
import Control.Lens.Internal.Bicontravariant
|
||
|
|
import Control.Lens.Optic
|
||
|
|
import Control.Lens.Optional
|
||
|
|
import Control.Lens.Getter
|
||
|
|
|
||
|
|
%default total
|
||
|
|
|
||
|
|
|
||
|
|
public export
|
||
|
|
record IsOptFold p where
|
||
|
|
constructor MkIsOptFold
|
||
|
|
runIsOptFold : (Strong p, Choice p, Cochoice p, Bicontravariant p)
|
||
|
|
|
||
|
|
export %hint
|
||
|
|
optFoldToOptional : IsOptFold p => IsOptional p
|
||
|
|
optFoldToOptional @{MkIsOptFold _} = MkIsOptional %search
|
||
|
|
|
||
|
|
export %hint
|
||
|
|
optFoldToGetter : IsOptFold p => IsGetter p
|
||
|
|
optFoldToGetter @{MkIsOptFold _} = MkIsGetter %search
|
||
|
|
|
||
|
|
|
||
|
|
public export
|
||
|
|
0 OptionalFold : (s,a : Type) -> Type
|
||
|
|
OptionalFold s a = Optic IsOptFold s s a a
|
||
|
|
|
||
|
|
|
||
|
|
public export
|
||
|
|
folding : (s -> Maybe a) -> OptionalFold s a
|
||
|
|
folding f @{MkIsOptFold _} =
|
||
|
|
contrabimap (\x => maybe (Left x) Right (f x)) Left . right
|
||
|
|
|
||
|
|
public export
|
||
|
|
filtered : (a -> Bool) -> OptionalFold a a
|
||
|
|
filtered p = folding (\x => if p x then Just x else Nothing)
|