8cb6d48 · rel8 · git.iko.soy

git.iko.soy/rel8

Generalize nullable to work on `Table`s

commit8cb6d488075a6e42ba8091c434c8f2c5dd16d266 authorShane O'Brien <shane.obrien@circuithub.com> dateThu 6 May 2021, 18:26 (6 years ago) parentd028b37

3 files changed+20−14

compare with master

unifiedsplit

src/Rel8/Expr/Null.hs+3−3 src/Rel8/Expr/Ord.hs+10−11 src/Rel8/Table/Bool.hs+7

src/Rel8/Expr/Null.hs+3−3

@@ -5,7 +5,7 @@

55{-# options -fno-warn-redundant-constraints #-}

77module Rel8.Expr.Null

8− ( null, snull, nullable, nullableOf

8+ ( null, snull, nullableExpr, nullableOf

99 , isNull, isNonNull

1010 , nullify, unsafeUnnullify

1111 , mapNull, liftOpNull

@@ -40,8 +40,8 @@ unsafeUnnullify (Expr a) = Expr a

4040

4141

4242-- | Like 'maybe', but to eliminate @null@.

43−nullable :: Expr b -> (Expr a -> Expr b) -> Expr (Maybe a) -> Expr b

44−nullable b f ma = boolExpr (f (unsafeUnnullify ma)) b (isNull ma)

43+nullableExpr :: Expr b -> (Expr a -> Expr b) -> Expr (Maybe a) -> Expr b

44+nullableExpr b f ma = boolExpr (f (unsafeUnnullify ma)) b (isNull ma)

4545

4646

4747nullableOf :: DBType a => Maybe (Expr a) -> Expr (Maybe a)

src/Rel8/Expr/Ord.hs+10−11

@@ -22,10 +22,9 @@ import qualified Opaleye.Internal.HaskellDB.PrimQuery as Opaleye

2222-- rel8

2323import Rel8.Expr ( Expr( Expr ) )

2424import Rel8.Expr.Bool ( (&&.), (||.), coalesce )

25−import Rel8.Expr.Null ( isNull, isNonNull, nullable, unsafeLiftOpNull )

25+import Rel8.Expr.Null ( isNull, isNonNull, nullableExpr, unsafeLiftOpNull )

2626import Rel8.Expr.Opaleye ( toPrimExpr, zipPrimExprsWith )

27−import Rel8.Schema.Null ( Nullity( Null, NotNull ), Sql )

28−import qualified Rel8.Schema.Null as Schema ( nullable )

27+import Rel8.Schema.Null ( Nullity( Null, NotNull ), Sql, nullable )

2928import Rel8.Type.Ord ( DBOrd )

3029

3130

@@ -49,7 +48,7 @@ ge = zipPrimExprsWith (Opaleye.BinExpr (Opaleye.:>=))

4948-- as @null@ will sort below any other value. For a version of @<@ that exactly

5049-- matches SQL, see '(<?)'.

5150(<.) :: forall a. Sql DBOrd a => Expr a -> Expr a -> Expr Bool

52−(<.) = case Schema.nullable @a of

51+(<.) = case nullable @a of

5352 Null -> \ma mb -> isNull ma &&. isNonNull mb ||. ma <? mb

5453 NotNull -> lt

5554infix 4 <.

@@ -59,7 +58,7 @@ infix 4 <.

5958-- as @null@ will sort below any other value. For a version of @<=@ that exactly

6059-- matches SQL, see '(<=?)'.

6160(<=.) :: forall a. Sql DBOrd a => Expr a -> Expr a -> Expr Bool

62−(<=.) = case Schema.nullable @a of

61+(<=.) = case nullable @a of

6362 Null -> \ma mb -> isNull ma ||. ma <=? mb

6463 NotNull -> le

6564infix 4 <=.

@@ -69,7 +68,7 @@ infix 4 <=.

6968-- as @null@ will sort below any other value. For a version of @>@ that exactly

7069-- matches SQL, see '(>?)'.

7170(>.) :: forall a. Sql DBOrd a => Expr a -> Expr a -> Expr Bool

72−(>.) = case Schema.nullable @a of

71+(>.) = case nullable @a of

7372 Null -> \ma mb -> isNonNull ma &&. isNull mb ||. ma >? mb

7473 NotNull -> gt

7574infix 4 >.

@@ -79,7 +78,7 @@ infix 4 >.

7978-- as @null@ will sort below any other value. For a version of @>=@ that

8079-- exactly matches SQL, see '(>=?)'.

8180(>=.) :: forall a. Sql DBOrd a => Expr a -> Expr a -> Expr Bool

82−(>=.) = case Schema.nullable @a of

81+(>=.) = case nullable @a of

8382 Null -> \ma mb -> isNull mb ||. ma >=? mb

8483 NotNull -> ge

8584infix 4 >=.

@@ -118,8 +117,8 @@ infix 4 >=?

118117--

119118-- Corresponds to the SQL @least()@ function.

120119leastExpr :: forall a. Sql DBOrd a => Expr a -> Expr a -> Expr a

121−leastExpr ma mb = case Schema.nullable @a of

122− Null -> nullable ma (\a -> nullable mb (least_ a) mb) ma

120+leastExpr ma mb = case nullable @a of

121+ Null -> nullableExpr ma (\a -> nullableExpr mb (least_ a) mb) ma

123122 NotNull -> least_ ma mb

124123 where

125124 least_ a b = Expr (Opaleye.FunExpr "LEAST" [toPrimExpr a, toPrimExpr b])

@@ -130,8 +129,8 @@ leastExpr ma mb = case Schema.nullable @a of

130129--

131130-- Corresponds to the SQL @greatest()@ function.

132131greatestExpr :: forall a. Sql DBOrd a => Expr a -> Expr a -> Expr a

133−greatestExpr ma mb = case Schema.nullable @a of

134− Null -> nullable mb (\a -> nullable ma (greatest_ a) mb) ma

132+greatestExpr ma mb = case nullable @a of

133+ Null -> nullableExpr mb (\a -> nullableExpr ma (greatest_ a) mb) ma

135134 NotNull -> greatest_ ma mb

136135 where

137136 greatest_ a b =

src/Rel8/Table/Bool.hs+7

@@ -5,6 +5,7 @@

55module Rel8.Table.Bool

66 ( bool

77 , case_

8+ , nullable

89 )

910where

1011

@@ -14,6 +15,7 @@ import Prelude

1415-- rel8

1516import Rel8.Expr ( Expr, Col(..) )

1617import Rel8.Expr.Bool ( boolExpr, caseExpr )

18+import Rel8.Expr.Null ( isNull, unsafeUnnullify )

1719import Rel8.Schema.HTable ( htabulate, hfield )

1820import Rel8.Table ( Table, fromColumns, toColumns )

1921

@@ -40,3 +42,8 @@ case_ (map (fmap toColumns) -> branches) (toColumns -> fallback) =

4042 DB fallbackExpr ->

4143 case map (fmap (unDB . (`hfield` field))) branches of

4244 branchExprs -> DB (caseExpr branchExprs fallbackExpr)

45+

46+

47+-- | Like 'maybe', but to eliminate @null@.

48+nullable :: Table Expr b => b -> (Expr a -> b) -> Expr (Maybe a) -> b

49+nullable b f ma = bool (f (unsafeUnnullify ma)) b (isNull ma)