squares-0.1: The double category of Hask functors and profunctors

License	BSD-style (see the file LICENSE)
Maintainer	sjoerd@w3future.com
Safe Haskell	Safe
Language	Haskell2010

Data.Functor.Square

Contents

Squares for Identity
Squares for Compose

Description

Synopsis

fromIdentity :: Square '[] '[] '[Identity] '[]
toIdentity :: Square '[] '[] '[] '[Identity]
fromCompose :: (Functor f, Functor g) => Square '[] '[] '[Compose g f] '[f, g]
toCompose :: (Functor f, Functor g) => Square '[] '[] '[f, g] '[Compose g f]

Squares for `Identity`

fromIdentity :: Square '[] '[] '[Identity] '[] Source #

 +--I--+
 |  v  |
 |  @  |
 |     |
 +-----+

toIdentity :: Square '[] '[] '[] '[Identity] Source #

+-----+
|     |
|  @  |
|  v  |
+--I--+

Squares for `Compose`

fromCompose :: (Functor f, Functor g) => Square '[] '[] '[Compose g f] '[f, g] Source #

 +-g.f-+
 |  v  |
 | /@\ |
 | v v |
 +-f-g-+

toCompose :: (Functor f, Functor g) => Square '[] '[] '[f, g] '[Compose g f] Source #

 +-f-g-+
 | v v |
 | \@/ |
 |  v  |
 +-g.f-+