Database.Relational.Pi

Contents

Description

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

Synopsis

Projection path

data Pi r0 r1 Source #

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) Source #	Map projection path `Pi` which has record result type.
Methods (\|$\|) :: ProductConstructor (a -> b) => (a -> b) -> Pi a a -> Pi a b #
ProductIsoApplicative (Pi a) Source #	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 Source #
Methods id :: cat a a # (.) :: cat b c -> cat a b -> cat a c #
ProductIsoEmpty (Pi a) () Source #
Methods pureE :: Pi a () # peRight :: Pi a (a, ()) -> Pi a a # peLeft :: Pi a ((), a) -> Pi a a #
PersistableWidth r0 => Show (Pi r0 r1) Source #
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 Source #

Compose projection path.

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

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

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

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

Identity projection path.