Copyright	(c) 2014 Patrick Bahr
License	BSD3
Maintainer	Patrick Bahr <[email protected]>
Stability	experimental
Portability	non-portable (GHC Extensions)
Safe Haskell	Safe-Inferred
Language	Haskell2010

Data.Comp.Multi.Projection

Description

This module provides a generic projection function pr for arbitrary nested binary products.

Synopsis

pr :: forall p q a. p :< q => q a -> p a
type (:<) f g = Proj (ComprEmb (Elem f g)) f g
data (f :*: g) a = (f a) :*: (g a)
ffst :: (f :*: g) a -> f a
fsnd :: (f :*: g) a -> g a

Documentation

pr :: forall p q a. p :< q => q a -> p a Source #

This function projects the component of type e out or the compound value of type p.

type (:<) f g = Proj (ComprEmb (Elem f g)) f g infixl 5 Source #

The constraint e :< p expresses that e is a component of the type p. That is, p is formed by binary products using the type e. The occurrence of e must be unique. For example we have Int :< (Bool,(Int,Bool)) but not Bool :< (Bool,(Int,Bool)).

data (f :*: g) a infixr 8 Source #

Formal product of signatures (functors).

Constructors

(f a) :*: (g a) infixr 8

Instances

Instances details

(Functor f, Functor g) => Functor (f :*: g) Source #
Instance details Defined in Data.Comp.Ops Methods fmap :: (a -> b) -> (f :: g) a -> (f :: g) b # (<$) :: a -> (f :: g) b -> (f :: g) a #
(Foldable f, Foldable g) => Foldable (f :*: g) Source #
Instance details Defined in Data.Comp.Ops Methods fold :: Monoid m => (f :: g) m -> m # foldMap :: Monoid m => (a -> m) -> (f :: g) a -> m # foldMap' :: Monoid m => (a -> m) -> (f :: g) a -> m # foldr :: (a -> b -> b) -> b -> (f :: g) a -> b # foldr' :: (a -> b -> b) -> b -> (f :: g) a -> b # foldl :: (b -> a -> b) -> b -> (f :: g) a -> b # foldl' :: (b -> a -> b) -> b -> (f :: g) a -> b # foldr1 :: (a -> a -> a) -> (f :: g) a -> a # foldl1 :: (a -> a -> a) -> (f :: g) a -> a # toList :: (f :: g) a -> [a] # null :: (f :: g) a -> Bool # length :: (f :: g) a -> Int # elem :: Eq a => a -> (f :: g) a -> Bool # maximum :: Ord a => (f :: g) a -> a # minimum :: Ord a => (f :: g) a -> a # sum :: Num a => (f :: g) a -> a # product :: Num a => (f :*: g) a -> a #
(Traversable f, Traversable g) => Traversable (f :*: g) Source #
Instance details Defined in Data.Comp.Ops Methods traverse :: Applicative f0 => (a -> f0 b) -> (f :: g) a -> f0 ((f :: g) b) # sequenceA :: Applicative f0 => (f :: g) (f0 a) -> f0 ((f :: g) a) # mapM :: Monad m => (a -> m b) -> (f :: g) a -> m ((f :: g) b) # sequence :: Monad m => (f :: g) (m a) -> m ((f :: g) a) #

ffst :: (f :*: g) a -> f a Source #

fsnd :: (f :*: g) a -> g a Source #