Database.Record.Persistable

This module defines interfaces between Haskell type and list of SQL type.

Specify SQL type

data PersistableSqlType q

Proof object to specify type q is SQL type

runPersistableNullValue :: PersistableSqlType q -> q

Null value of SQL type q.

unsafePersistableSqlTypeFromNull

Arguments

:: q

SQL null value of SQL type q

-> PersistableSqlType q

Result proof object

Unsafely generate PersistableSqlType proof object from specified SQL null value which type is q.

Specify record width

type PersistableRecordWidth a = ProductConst (Sum Int) a

Proof object to specify width of Haskell type a when converting to SQL type list.

runPersistableRecordWidth :: PersistableRecordWidth a -> Int

Get width Int value of record type a.

unsafePersistableRecordWidth

Arguments

:: Int

Specify width of Haskell type a

-> PersistableRecordWidth a

Result proof object

Unsafely generate PersistableRecordWidth proof object from specified width of Haskell type a.

unsafeValueWidth :: PersistableRecordWidth a

Unsafely generate PersistableRecordWidth proof object for Haskell type a which is single column type.

(<&>) :: PersistableRecordWidth a -> PersistableRecordWidth b -> PersistableRecordWidth (a, b)

Derivation rule of PersistableRecordWidth for tuple (,) type.

maybeWidth :: PersistableRecordWidth a -> PersistableRecordWidth (Maybe a)

Derivation rule of PersistableRecordWidth from from Haskell type a into for Haskell type Maybe a.

Inference rules for proof objects

class Eq q => PersistableType q where

Interface of inference rule for PersistableSqlType proof object

Minimal complete definition

persistableType

Methods

persistableType :: PersistableSqlType q

sqlNullValue :: PersistableType q => q

Inferred Null value of SQL type.

class PersistableWidth a where

Interface of inference rule for PersistableRecordWidth proof object

Methods

persistableWidth :: PersistableRecordWidth a

persistableWidth :: (Generic a, GFieldWidthList (Rep a)) => PersistableRecordWidth a

Instances

PersistableWidth ()

Inference rule of PersistableRecordWidth for Haskell unit () type. Derive from axiom.

Methods

persistableWidth :: PersistableRecordWidth ()

PersistableWidth a => PersistableWidth (Maybe a)

Inference rule of PersistableRecordWidth proof object for Maybe type.

Methods

persistableWidth :: PersistableRecordWidth (Maybe a)

derivedWidth :: PersistableWidth a => (PersistableRecordWidth a, Int)

Pass type parameter and inferred width value.

low-level interfaces

class GFieldWidthList f

Generic width value list of record fields.

Minimal complete definition

gFieldWidthList

Instances

GFieldWidthList U1

Methods

gFieldWidthList :: ProductConst (DList Int) (U1 a)

PersistableWidth a => GFieldWidthList (K1 i a)

Methods

gFieldWidthList :: ProductConst (DList Int) (K1 i a a)

(GFieldWidthList a, GFieldWidthList b) => GFieldWidthList ((:*:) a b)

Methods

gFieldWidthList :: ProductConst (DList Int) ((a :*: b) a)

GFieldWidthList a => GFieldWidthList (M1 i c a)

Methods

gFieldWidthList :: ProductConst (DList Int) (M1 i c a a)

data ProductConst a b

Restricted in product isomorphism record type b

Instances

Show a => Show (ProductConst a b)

Methods

showsPrec :: Int -> ProductConst a b -> ShowS

show :: ProductConst a b -> String

showList :: [ProductConst a b] -> ShowS

getProductConst :: ProductConst a b -> a

extract constant value of ProductConst.

genericFieldOffsets :: (Generic a, GFieldWidthList (Rep a)) => ProductConst (Array Int Int) a

Generic offset array of record fields.