11a2229 · rel8 · git.iko.soy

git.iko.soy/rel8

Simplify Column type family

Now that the Field type family only needs a Necessity and a Type, we don't need to "parse" the Type to find the Necessity, we can instead just make it so that Column creates a Required field, and repurpose the name Default to be a type family that creates an Optional field. The previous "parsing" approach was brittle sometimes, particularly in the case of polymorphism.

commit11a22291aba47e5d0ebf269dbca166a552112c65 authorShane O'Brien <shane.obrien@circuithub.com> dateWed 14 Apr 2021, 07:25 (6 years ago) parent5e4df50

2 files changed+7−20

compare with master

unifiedsplit

src/Rel8/Schema/Column.hs+5−18 src/Rel8/Schema/Generic/Test.hs+2−2

src/Rel8/Schema/Column.hs+5−18

@@ -17,26 +17,13 @@ import Rel8.Schema.Field ( Field )

1717import qualified Rel8.Schema.Kind as K

1818

1919

20−type Default :: Type -> Type

21−data Default a

22−

23−

24−type GetNecessity :: Type -> Necessity

25−type family GetNecessity a where

26− GetNecessity (Default _) = 'Optional

27− GetNecessity _ = 'Required

28−

29−

30−type UnwrapDefault :: Type -> Type

31−type family UnwrapDefault a where

32− UnwrapDefault (Default a) = a

33− UnwrapDefault a = a

34−

35−

3620-- | The @Column@ type family should be used to indicate which fields of your

3721-- data types are single columns in queries. This type family has special

3822-- support when a query is executed, allowing you to use a single data type for

3923-- both query data and rows decoded to Haskell.

4024type Column :: K.Context -> Type -> Type

41−type Column context a =

42− Field context (GetNecessity a) (UnwrapDefault a)

25+type Column context a = Field context 'Required a

26+

27+

28+type Default :: K.Context -> Type -> Type

29+type Default context a = Field context 'Optional a

src/Rel8/Schema/Generic/Test.hs+2−2

@@ -31,7 +31,7 @@ data Table f = Table

3131

3232

3333data TablePair f = TablePair

34− { foo :: Column f (Default Bool)

34+ { foo :: Default f Bool

3535 , bars :: (Column f Text, Column f Text)

3636 }

3737 deriving stock Generic

@@ -72,7 +72,7 @@ data TableList f = TableList

7272

7373data TableNonEmpty f = TableNonEmpty

7474 { foo :: Column f Bool

75− , bars :: HNonEmpty f (TableList f)

75+ , bars :: HNonEmpty f (TableList f, Default f Char)

7676 }

7777 deriving stock Generic

7878 deriving anyclass Rel8able