Database.Relational.Pi

This module defines typed projection path objects. Contains normal interfaces.

Projection path

data Pi r0 r1

Projection path from type r0 into type r1. This type also indicate key object which type is r1 for record type r0.

Instances

ProductIsoFunctor (Pi a)

Map projection path Pi which has record result type.

Methods

(|$|) :: ProductConstructor (a -> b) => (a -> b) -> Pi a a -> Pi a b

ProductIsoApplicative (Pi a)

Compose projection path Pi which has record result type using applicative style.

Methods

pureP :: ProductConstructor a => a -> Pi a a

(|*|) :: Pi a (a -> b) -> Pi a a -> Pi a b

Category * Pi

Methods

id :: cat a a

(.) :: cat b c -> cat a b -> cat a c

ProductIsoEmpty (Pi a) ()

Methods

pureE :: Pi a ()

peRight :: Pi a (a, ()) -> Pi a a

peLeft :: Pi a ((), a) -> Pi a a

PersistableWidth r0 => Show (Pi r0 r1)

Methods

showsPrec :: Int -> Pi r0 r1 -> ShowS

show :: Pi r0 r1 -> String

showList :: [Pi r0 r1] -> ShowS

(<.>) :: Pi a b -> Pi b c -> Pi a c infixl 8

Compose projection path.

(<?.>) :: Pi a (Maybe b) -> Pi b c -> Pi a (Maybe c) infixl 8

Compose projection path. Maybe phantom functor is map-ed.

(<?.?>) :: Pi a (Maybe b) -> Pi b (Maybe c) -> Pi a (Maybe c) infixl 8

Compose projection path. Maybe phantom functors are join-ed like >=>.

id' :: Pi a a

Identity projection path.