Safe Haskell	None
Language	Haskell2010

Data.Lazify

Description

Record types in Haskell can be made lazy through lazy pattern matching. This module offers functions for making them lazy generically.

Synopsis

class Lazifiable a where
- lazify :: a -> a
genericLazify :: forall a. (Generic a, GLazifiable a (Rep a)) => a -> a
($~) :: forall rep a (b :: TYPE rep). Lazifiable a => (a -> b) -> a -> b

Documentation

class Lazifiable a where Source #

A class for types that can be lazified. A generic default is provided for convenience. To lazify a type using its generic representation, use genericLazify.

Minimal complete definition

Nothing

Methods

lazify :: a -> a Source #

Lazily rewrap a record. Applying lazify to a record and then pattern matching on it strictly is equivalent to pattern matching on it lazily.

strictFirst :: (a -> a') -> (a, b) -> (a', b)
strictFirst f (a, b) = (f a, b)

lazyFirst :: (a -> a') -> (a, b) -> (a', b)
lazyFirst f = strictFirst f . lazify
-- Equivalently
lazyFirst f ~(a, b) = (f a, b)

default lazify :: (Generic a, GLazifiable a (Rep a)) => a -> a Source #

Instances

Instances details

Lazifiable () Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: () -> () Source #
Lazifiable a => Lazifiable (Min a) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: Min a -> Min a Source #
Lazifiable a => Lazifiable (Max a) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: Max a -> Max a Source #
Lazifiable a => Lazifiable (First a) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: First a -> First a Source #
Lazifiable a => Lazifiable (Last a) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: Last a -> Last a Source #
Lazifiable a => Lazifiable (WrappedMonoid a) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: WrappedMonoid a -> WrappedMonoid a Source #
Lazifiable a => Lazifiable (Identity a) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: Identity a -> Identity a Source #
Lazifiable a => Lazifiable (Dual a) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: Dual a -> Dual a Source #
Lazifiable a => Lazifiable (Sum a) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: Sum a -> Sum a Source #
Lazifiable a => Lazifiable (Product a) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: Product a -> Product a Source #
Lazifiable (NonEmpty a) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: NonEmpty a -> NonEmpty a Source #
Lazifiable (Tree a) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: Tree a -> Tree a Source #
Typeable a => Lazifiable (TypeRep a) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: TypeRep a -> TypeRep a Source #
Lazifiable (a, b) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: (a, b) -> (a, b) Source #
Lazifiable (Arg a b) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: Arg a b -> Arg a b Source #
Lazifiable (Proxy a) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: Proxy a -> Proxy a Source #
Lazifiable (a, b, c) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: (a, b, c) -> (a, b, c) Source #
Lazifiable a => Lazifiable (Const a b) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: Const a b -> Const a b Source #
Lazifiable (f a) => Lazifiable (Ap f a) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: Ap f a -> Ap f a Source #
Lazifiable (f a) => Lazifiable (Alt f a) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: Alt f a -> Alt f a Source #
Coercible a b => Lazifiable (Coercion a b) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: Coercion a b -> Coercion a b Source #
a ~ b => Lazifiable (a :~: b) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: (a :~: b) -> a :~: b Source #
Lazifiable b => Lazifiable (Tagged a b) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: Tagged a b -> Tagged a b Source #
Lazifiable (t a) => Lazifiable (Reverse t a) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: Reverse t a -> Reverse t a Source #
Lazifiable (f a) => Lazifiable (IdentityT f a) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: IdentityT f a -> IdentityT f a Source #
Lazifiable (f a) => Lazifiable (Backwards f a) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: Backwards f a -> Backwards f a Source #
Lazifiable (a, b, c, d) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: (a, b, c, d) -> (a, b, c, d) Source #
Lazifiable (Product f g a) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: Product f g a -> Product f g a Source #
a ~~ b => Lazifiable (a :~~: b) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: (a :~~: b) -> a :~~: b Source #
Lazifiable (f (g a)) => Lazifiable ((f :.: g) a) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: (f :.: g) a -> (f :.: g) a Source #
Lazifiable (a, b, c, d, e) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: (a, b, c, d, e) -> (a, b, c, d, e) Source #
Lazifiable (f (g a)) => Lazifiable (Compose f g a) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: Compose f g a -> Compose f g a Source #
Lazifiable (a, b, c, d, e, f) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: (a, b, c, d, e, f) -> (a, b, c, d, e, f) Source #
Lazifiable (a, b, c, d, e, f, g) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: (a, b, c, d, e, f, g) -> (a, b, c, d, e, f, g) Source #
Lazifiable (a, b, c, d, e, f, g, h) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: (a, b, c, d, e, f, g, h) -> (a, b, c, d, e, f, g, h) Source #
Lazifiable (a, b, c, d, e, f, g, h, i) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: (a, b, c, d, e, f, g, h, i) -> (a, b, c, d, e, f, g, h, i) Source #
Lazifiable (a, b, c, d, e, f, g, h, i, j) Source #
Instance details Defined in Data.Lazify.Internal Methods lazify :: (a, b, c, d, e, f, g, h, i, j) -> (a, b, c, d, e, f, g, h, i, j) Source #

genericLazify :: forall a. (Generic a, GLazifiable a (Rep a)) => a -> a Source #

Lazify a record using its generic representation.

Note that newtypes are treated specially: a newtype is lazified by lazifying its underlying type using its Lazifiable instance.

($~) :: forall rep a (b :: TYPE rep). Lazifiable a => (a -> b) -> a -> b Source #

Apply a function to a lazified value.

Note to users of TypeApplications: For GHC >= 9.0.1, the representation is marked as inferred. Before that, doing so is impossible and the representation must be passed as the first type argument. I'm sorry.