Port to Opaleye lateral branch

rel8.cabal

@@ -25,7 +25,7 @@ library
     , case-insensitive
     , contravariant
     , hasql ^>= 1.4.5.1
-    , opaleye ^>= 0.7.2.0
+    , opaleye ^>= 0.7.3.0
     , profunctors
     , scientific
     , semialign

src/Rel8/Query.hs

@@ -169,14 +169,14 @@ instance Bind Query where
 
 
 instance Monad Query where
-  Query q >>= f = Query $ \dummies -> Opaleye.QueryArr $ \(_, query, tag) ->
+  Query q >>= f = Query $ \dummies -> Opaleye.QueryArr $ \(_, tag) ->
     let
       Opaleye.QueryArr qa = q dummies
-      ((m, a), query', tag') = qa ((), query, tag)
+      ((m, a), query, tag') = qa ((), tag)
       Query q' = f a
-      (dummies', query'', tag'') =
+      (dummies', query', tag'') =
         ( dummy : dummies
-        , Opaleye.Rebind True bindings query'
+        , \lateral -> Opaleye.Rebind True bindings . query lateral
         , Opaleye.next tag'
         )
         where
@@ -185,19 +185,13 @@ instance Monad Query where
               random = Opaleye.FunExpr "random" []
               name = Opaleye.extractAttr "dummy" tag'
       Opaleye.QueryArr qa' = Opaleye.lateral $ \_ -> q' dummies'
-      -- NOTE: query''' and needsDummies are corecursive; only laziness saves
-      -- us here.
-      --
-      -- This refactoring, if adopted, would allow us to do this without
-      -- relying on laziness:
-      -- https://github.com/tomjaguarpaw/haskell-opaleye/commit/8a23f5028ab7396290984d63a8316949909fdbb4
-      ((m'@(Any needsDummies), b), query'''', tag''') = qa' ((), query''', tag'')
+      ((m'@(Any needsDummies), b), query'', tag''') = qa' ((), tag'')
       query'''
-        | needsDummies = query''
-        | otherwise = query'
+        | needsDummies = \lateral -> query'' lateral . query' lateral
+        | otherwise = \lateral -> query'' lateral . query lateral
       m'' = m <> m'
     in
-      ((m'', b), query'''', tag''')
+      ((m'', b), query''', tag''')
 
 
 -- | '<|>:' = 'unionAll'.

src/Rel8/Query/Evaluate.hs

@@ -55,13 +55,13 @@ laterally a = Query $ \bindings -> pure $ (Any True,) $
 -- variable in the SQL. The @a@ returned consists only of these
 -- variables. It's essentially a @let@ binding for Postgres expressions.
 rebind :: Table Expr a => a -> Query a
-rebind a = Query $ \_ -> Opaleye.QueryArr $ \(_, query, tag) ->
+rebind a = Query $ \_ -> Opaleye.QueryArr $ \(_, tag) ->
   let
     tag' = Opaleye.next tag
     (a', bindings) = Opaleye.run $
       Opaleye.runUnpackspec unpackspec (Opaleye.extractAttr "eval" tag') a
   in
-    ((mempty, a'), Opaleye.Rebind True bindings query, tag')
+    ((mempty, a'), \_ -> Opaleye.Rebind True bindings, tag')
 
 
 foldl1' :: (a -> a -> a) -> NonEmpty a -> a

src/Rel8/Query/Maybe.hs

@@ -9,15 +9,11 @@ where
 import Prelude
 
 -- opaleye
-import qualified Opaleye.Internal.PackMap as Opaleye
-import qualified Opaleye.Internal.PrimQuery as Opaleye
-import qualified Opaleye.Internal.QueryArr as Opaleye
-import qualified Opaleye.Internal.Tag as Opaleye
+import qualified Opaleye.Internal.MaybeFields as Opaleye
 
 -- rel8
-import Rel8.Expr.Bool ( true )
 import Rel8.Expr.Eq ( (==.) )
-import Rel8.Expr.Opaleye ( toPrimExpr, traversePrimExpr )
+import Rel8.Expr.Opaleye ( fromColumn, fromPrimExpr )
 import Rel8.Query ( Query )
 import Rel8.Query.Filter ( where_ )
 import Rel8.Query.Opaleye ( mapOpaleye )
@@ -31,18 +27,10 @@ import Rel8.Table.Tag ( Tag(..), fromExpr )
 -- To speak in more concrete terms, 'optional' is most useful to write @LEFT
 -- JOIN@s.
 optional :: Query a -> Query (MaybeTable a)
-optional = mapOpaleye $ \query -> Opaleye.QueryArr $ \i -> case i of
-  (_, left, tag) -> (ma', join, tag'')
-    where
-      (ma, right, tag') = Opaleye.runSimpleQueryArr (pure <$> query) ((), tag)
-      MaybeTable Tag {expr = just} a = ma
-      (just', bindings) = Opaleye.run $ do
-        traversePrimExpr (Opaleye.extractAttr "isJust" tag') just
-      tag'' = Opaleye.next tag'
-      join = Opaleye.Join Opaleye.LeftJoin on [] bindings left right
-        where
-          on = toPrimExpr true
-      ma' = MaybeTable (fromExpr just') a
+optional =
+  mapOpaleye $
+    Opaleye.optionalInternal $
+      MaybeTable . fromExpr . fromPrimExpr . fromColumn
 
 
 -- | Filter out 'MaybeTable's, returning only the tables that are not-null.

src/Rel8/Query/Opaleye.hs

@@ -40,23 +40,23 @@ zipOpaleyeWith f (Query a) (Query b) = Query $ liftA2 (zipping f) a b
 mapping :: ()
   => (Opaleye.Select a -> Opaleye.Select b)
   -> Opaleye.Select (m, a) -> Opaleye.Select (m, b)
-mapping f q@(Opaleye.QueryArr qa) = Opaleye.QueryArr $ \(_, query, tag) ->
+mapping f q@(Opaleye.QueryArr qa) = Opaleye.QueryArr $ \(_, tag) ->
   let
-    ((m, _), _, _) = qa ((), query, tag)
+    ((m, _), _, _) = qa ((), tag)
     Opaleye.QueryArr qa' = (m,) <$> f (snd <$> q)
   in
-    qa' ((), query, tag)
+    qa' ((), tag)
 
 
 zipping :: Semigroup m
   => (Opaleye.Select a -> Opaleye.Select b -> Opaleye.Select c)
   -> Opaleye.Select (m, a) -> Opaleye.Select (m, b) -> Opaleye.Select (m, c)
 zipping f q@(Opaleye.QueryArr qa) q'@(Opaleye.QueryArr qa') =
-  Opaleye.QueryArr $ \(_, query, tag) ->
+  Opaleye.QueryArr $ \(_, tag) ->
     let
-      ((m, _), _, _) = qa ((), query, tag)
-      ((m', _), _, _) = qa' ((), query, tag)
+      ((m, _), _, _) = qa ((), tag)
+      ((m', _), _, _) = qa' ((), tag)
       m'' = m <> m'
       Opaleye.QueryArr qa'' = (m'',) <$> f (snd <$> q) (snd <$> q')
     in
-      qa'' ((), query, tag)
+      qa'' ((), tag)

src/Rel8/Query/These.hs

@@ -46,7 +46,7 @@ alignBy :: ()
   => (a -> b -> Expr Bool)
   -> Query a -> Query b -> Query (TheseTable a b)
 alignBy condition = zipOpaleyeWith $ \left right -> Opaleye.QueryArr $ \i -> case i of
-  (_, input, tag) -> (tab, join', tag''')
+  (_, tag) -> (tab, join', tag''')
     where
       (ma, left', tag') = Opaleye.runSimpleQueryArr (pure <$> left) ((), tag)
       (mb, right', tag'') = Opaleye.runSimpleQueryArr (pure <$> right) ((), tag')
@@ -57,13 +57,15 @@ alignBy condition = zipOpaleyeWith $ \left right -> Opaleye.QueryArr $ \i -> cas
       (hasThere', rbindings) = Opaleye.run $ do
         traversePrimExpr (Opaleye.extractAttr "hasThere" tag'') hasThere
       tag''' = Opaleye.next tag''
-      join = Opaleye.Join Opaleye.FullJoin on lbindings rbindings left' right'
+      join lateral = Opaleye.Join Opaleye.FullJoin on left'' right''
         where
           on = toPrimExpr $ condition a b
+          left'' = (lateral, Opaleye.Rebind True lbindings left')
+          right'' = (lateral, Opaleye.Rebind True rbindings right')
       ma' = MaybeTable (fromExpr hasHere') a
       mb' = MaybeTable (fromExpr hasThere') b
       tab = TheseTable {here = ma', there = mb'}
-      join' = Opaleye.times input join
+      join' lateral input = Opaleye.times lateral input (join lateral)
 
 
 -- | Filter 'TheseTable's, keeping only 'thisTable's and 'thoseTable's.

tests/Main.hs

@@ -759,13 +759,13 @@ testEvaluate = databasePropertyTest "evaluate has the evaluation order we expect
 
     normalize selected' ===
       [ (('a', 'd'), (0, 0))
-      , (('b', 'd'), (1, 1))
-      , (('c', 'd'), (2, 2))
-      , (('a', 'e'), (3, 3))
+      , (('a', 'e'), (1, 1))
+      , (('a', 'f'), (2, 2))
+      , (('b', 'd'), (3, 3))
       , (('b', 'e'), (4, 4))
-      , (('c', 'e'), (5, 5))
-      , (('a', 'f'), (6, 6))
-      , (('b', 'f'), (7, 7))
+      , (('b', 'f'), (5, 5))
+      , (('c', 'd'), (6, 6))
+      , (('c', 'e'), (7, 7))
       , (('c', 'f'), (8, 8))
       ]