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

HasProjection l a b => IsLabel l (Pi a b)

Derive IsLabel instance from HasProjection.

Defined in Database.Relational.OverloadedProjection

Methods

fromLabel :: Pi a b

ProductIsoFunctor (Pi a)

Map projection path Pi which has record result type.

Defined in Database.Relational.Pi.Unsafe

Methods

(|$|) :: ProductConstructor (a0 -> b) => (a0 -> b) -> Pi a a0 -> Pi a b

ProductIsoApplicative (Pi a)

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

Defined in Database.Relational.Pi.Unsafe

Methods

pureP :: ProductConstructor a0 => a0 -> Pi a a0

(|*|) :: Pi a (a0 -> b) -> Pi a a0 -> Pi a b

Category Pi

Defined in Database.Relational.Pi.Unsafe

Methods

id :: Pi a a

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

ProductIsoEmpty (Pi a) ()

Defined in Database.Relational.Pi.Unsafe

Methods

pureE :: Pi a ()

peRight :: Pi a (a0, ()) -> Pi a a0

peLeft :: Pi a ((), a0) -> Pi a a0

PersistableWidth r0 => Show (Pi r0 r1)

Defined in Database.Relational.Pi.Unsafe

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.

Low-level API

expandIndexes' :: PersistableRecordWidth a -> Pi a b -> [Int]

Expand indexes from key.

expandIndexes :: PersistableWidth a => Pi a b -> [Int]

Expand indexes from key. Infered width version.