80b72b3 · typeable/aeson

git.iko.soy/typeable/aeson

Specialize ToJSON for common types

Here's a motivating example: ``` mkArray :: [Value] -> Array mkArray = Vector.fromList mkObject :: [(Text, Value)] -> Object mkObject = HashMap.fromList someArray :: Array someArray = mkArray [toJSON (mkObject ["dummy" .=== mkObject ["dummy" .=== "dummy", "dummy" .=== "dummy", "dummy" .=== 42, "dummy" .=== 42], "dummy" .=== mkArray [toJSON "dummy", toJSON "dummy"], "dummy" .=== mkObject ["dummy" .=== 42, "dummy" .=== 42], "dummy" .=== mkArray [toJSON "dummy"]])] ``` If `aeson` doesn't pre-specialize, every time this example is compiled you pay the cost of specialization. In this case this blows up the number of terms from 181 to 2464 making compile time significantly slower than necessary.

commit80b72b3561c8f539fce13ce6d45b26d68a6c60ca authorBartosz Nitka <bnitka@fb.com> dateWed 26 Oct 2016, 19:05 (10 years ago) parentbd9c2d1

1 file changed+9

compare with master

unifiedsplit

Data/Aeson/Types/ToJSON.hs+9

Data/Aeson/Types/ToJSON.hs+9

@@ -615,6 +615,11 @@ instance ToJSON1 [] where

615615 {-# INLINE liftToEncoding #-}

616616

617617instance (ToJSON a) => ToJSON [a] where

618+ {-# SPECIALIZE instance ToJSON String #-}

619+ {-# SPECIALIZE instance ToJSON [String] #-}

620+ {-# SPECIALIZE instance ToJSON [Array] #-}

621+ {-# SPECIALIZE instance ToJSON [Object] #-}

622+

618623 toJSON = toJSON1

619624 {-# INLINE toJSON #-}

620625

@@ -1865,6 +1870,8 @@ instance ToJSON1 Vector where

18651870 {-# INLINE liftToEncoding #-}

18661871

18671872instance (ToJSON a) => ToJSON (Vector a) where

1873+ {-# SPECIALIZE instance ToJSON Array #-}

1874+

18681875 toJSON = toJSON1

18691876 {-# INLINE toJSON #-}

18701877

@@ -1936,6 +1943,8 @@ instance ToJSONKey k => ToJSON1 (H.HashMap k) where

19361943 {-# INLINE liftToEncoding #-}

19371944

19381945instance (ToJSON v, ToJSONKey k) => ToJSON (H.HashMap k v) where

1946+ {-# SPECIALIZE instance ToJSON Object #-}

1947+

19391948 toJSON = toJSON1

19401949 {-# INLINE toJSON #-}

19411950