Add between function

src/Database/Esqueleto.hs

@@ -44,7 +44,7 @@ module Database.Esqueleto
              , val, isNothing, just, nothing, joinV, withNonNull
              , countRows, count, countDistinct
              , not_, (==.), (>=.), (>.), (<=.), (<.), (!=.), (&&.), (||.)
-             , (+.), (-.), (/.), (*.)
+             , between, (+.), (-.), (/.), (*.)
              , random_, round_, ceiling_, floor_
              , min_, max_, sum_, avg_, castNum, castNumM
              , coalesce, coalesceDefault

src/Database/Esqueleto/Internal/Language.hs

@@ -352,6 +352,8 @@ class (Functor query, Applicative query, Monad query) =>
   (/.)  :: PersistField a => expr (Value a) -> expr (Value a) -> expr (Value a)
   (*.)  :: PersistField a => expr (Value a) -> expr (Value a) -> expr (Value a)
 
+  between :: PersistField typ => expr (Value typ) -> expr (Value typ) -> expr (Value typ) -> expr (Value Bool)
+
 
   random_  :: (PersistField a, Num a) => expr (Value a)
   round_   :: (PersistField a, Num a, PersistField b, Num b) => expr (Value a) -> expr (Value b)

src/Database/Esqueleto/Internal/Sql.hs

@@ -533,6 +533,12 @@ instance Esqueleto SqlQuery SqlExpr SqlBackend where
   (/.)  = unsafeSqlBinOp " / "
   (*.)  = unsafeSqlBinOp " * "
 
+  between a@(ERaw _ _) (ERaw _ f) (ERaw _ g) = unsafeSqlBinOp " BETWEEN " a $ ERaw Never $ \x ->
+    let (_, fv) = f x
+        (_, gv) = g x
+    in  (" ? AND ? ", fv ++ gv)
+  between _ _ _                              = throw (CompositeKeyErr NotError)
+
   random_  = unsafeSqlValue "RANDOM()"
   round_   = unsafeSqlFunction "ROUND"
   ceiling_ = unsafeSqlFunction "CEILING"

test/Common/Test.hs

@@ -630,6 +630,16 @@ testSelectWhere run = do
                return p
         liftIO $ ret `shouldBe` [ p3e ]
 
+    it "works for a simple example with between and [uses just . val]" $
+      run $ do
+        p1e  <- insert' p1
+        _    <- insert' p2
+        _    <- insert' p3
+        ret  <- select $
+          from $ \p -> do
+            where_ (between (p ^. PersonAge) (just $ val 20) (just $ val 40))
+            return p
+        liftIO $ ret `shouldBe` [ p1e ]
     it "works with avg_" $
       run $ do
         _ <- insert' p1