Data.Functor.Holey

The Holey type family

type family Holey f

If T is a type that is defined as a fixpoint, then a Holey T will be the type of "Ts with holes".

Instances

type Holey (Fix f)

type Holey (Fix f) = Fix (HoleF f)

Types

data HoleF f t

HoleF f transforms the functor f to add "holes".

Constructors

HoleF

A hole.

ExistingF (f t)

A normal value.

Instances

Decomposed HoleF

Methods

fmap1 :: (f t -> g t) -> HoleF f t -> HoleF g t

Functor f => Functor (HoleF f)

Methods

fmap :: (a -> b) -> HoleF f a -> HoleF f b

(<$) :: a -> HoleF f b -> HoleF f a

Eq (f t) => Eq (HoleF f t)

Methods

(==) :: HoleF f t -> HoleF f t -> Bool

(/=) :: HoleF f t -> HoleF f t -> Bool

Ord (f t) => Ord (HoleF f t)

Methods

compare :: HoleF f t -> HoleF f t -> Ordering

(<) :: HoleF f t -> HoleF f t -> Bool

(<=) :: HoleF f t -> HoleF f t -> Bool

(>) :: HoleF f t -> HoleF f t -> Bool

(>=) :: HoleF f t -> HoleF f t -> Bool

max :: HoleF f t -> HoleF f t -> HoleF f t

min :: HoleF f t -> HoleF f t -> HoleF f t

Pretty (f (Fix (HoleF f))) => Pretty (HoleF f (Fix (HoleF f)))

Pretty-printer for holes.

Methods

pretty :: HoleF f (Fix (HoleF f)) -> String

Patterns for hiding Fix

pattern Hole :: forall t. Fix (HoleF t)

pattern Existing :: forall t. t (Fix (HoleF t)) -> Fix (HoleF t)

Utility functions

whole :: Functor f => Fix f -> Fix (HoleF f)

Upgrade a value of type T to a value of type T-with-holes, without actually introducing any holes.

plug :: Functor f => Fix f -> Fix (HoleF f) -> Fix f

Fill all holes in a data structure with the given value.

punch :: Functor f => (Fix f -> Bool) -> Fix f -> Fix (HoleF f)

Replace any substructure matching the predicate with a hole.