Add ToJSON instances for IntN, UintN and generated datatypes (#136)

* Add ToJSON instances for IntN and UIntN

* Add ToJSON instances to generated data types

packages/ethereum/package.yaml

@@ -15,6 +15,7 @@ dependencies:
 - text                 >1.2  && <1.3
 - vinyl                >0.5  && <0.14
 - aeson                >1.2  && <2.2
+- aeson-casing         >=0.2 && <0.3
 - tagged               >0.8  && <0.9
 - memory               >0.14 && <0.17
 - relapse              >=1.0 && <2.0

packages/ethereum/src/Network/Ethereum/Contract/TH.hs

@@ -1,5 +1,6 @@
 {-# LANGUAGE FlexibleContexts  #-}
 {-# LANGUAGE LambdaCase        #-}
+{-# LANGUAGE BangPatterns      #-}
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE QuasiQuotes       #-}
 {-# LANGUAGE TemplateHaskell   #-}
@@ -45,7 +46,8 @@ module Network.Ethereum.Contract.TH
 
 import           Control.Applicative              ((<|>))
 import           Control.Monad                    (replicateM, (<=<))
-import qualified Data.Aeson                       as Aeson (encode)
+import qualified Data.Aeson                       as Aeson
+import           Data.Aeson.Casing                (aesonDrop, camelCase)
 import           Data.ByteArray                   (convert)
 import           Data.ByteArray.HexString         (HexString)
 import           Data.Char                        (toLower, toUpper)
@@ -207,6 +209,7 @@ mkDecl ev@(DEvent uncheckedName inputs anonymous) = sequence
     , instanceD' nonIndexedName (conT ''AbiGet) []
     , dataD' allName (recC allName (map (\(n, a) -> (\(b,t) -> return (n,b,t)) <=< toBang <=< typeEventQ $ a) allArgs)) derivingD
     , instanceD' allName (conT ''Generic) []
+    , instanceD' allName (conT ''Aeson.ToJSON) [funD' 'Aeson.toJSON [] [| Aeson.genericToJSON $ aesonDrop nameL (init' . camelCase) |] ]
     , instanceD (cxt [])
         (pure $ ConT ''IndexedEvent `AppT` ConT indexedName `AppT` ConT nonIndexedName `AppT` ConT allName)
         [funD' 'isAnonymous [] [|const anonymous|]]
@@ -216,6 +219,7 @@ mkDecl ev@(DEvent uncheckedName inputs anonymous) = sequence
     ]
   where
     name = if toLower (T.head uncheckedName) == Char.toUpper (T.head uncheckedName) then "EvT" <> uncheckedName else uncheckedName
+    !nameL = length (T.unpack name)
     topics    = [Just (T.unpack $ eventId ev)] <> replicate (length indexedArgs) Nothing
     toBang ty = bangType (bang sourceNoUnpack sourceStrict) (return ty)
     tag (n, ty) = AppT (AppT (ConT ''Tagged) (LitT $ NumTyLit n)) <$> typeEventQ ty
@@ -251,6 +255,11 @@ mkDecl fun@(DFunction name constant inputs outputs) = (++)
 
 mkDecl _ = return []
 
+-- | Best-effort name recovery from ADT to original 'eveArgName' on inputs.
+init' :: String -> String
+init' [] = []
+init' xs = if Char.isDigit (last xs) then xs else init xs
+
 mkContractDecl :: Text -> Text -> Text -> Declaration -> DecsQ
 mkContractDecl name a b (DConstructor inputs) = sequence
     [ dataD' dataName (normalC dataName bangInput) derivingD

packages/ethereum/web3-ethereum.cabal

@@ -1,6 +1,6 @@
 cabal-version: 1.12
 
--- This file has been generated from package.yaml by hpack version 0.34.4.
+-- This file has been generated from package.yaml by hpack version 0.34.7.
 --
 -- see: https://github.com/sol/hpack
 
@@ -58,6 +58,7 @@ library
   build-depends:
       OneTuple >0.2 && <0.4
     , aeson >1.2 && <2.2
+    , aeson-casing ==0.2.*
     , base >4.11 && <4.16
     , bytestring >0.10 && <0.11
     , data-default >0.7 && <0.8
@@ -122,6 +123,7 @@ test-suite tests
   build-depends:
       OneTuple >0.2 && <0.4
     , aeson >1.2 && <2.2
+    , aeson-casing ==0.2.*
     , base >4.11 && <4.16
     , bytestring >0.10 && <0.11
     , data-default >0.7 && <0.8

packages/solidity/src/Data/Solidity/Prim/Int.hs

@@ -34,6 +34,7 @@ module Data.Solidity.Prim.Int
 import qualified Basement.Numerical.Number as Basement (toInteger)
 import           Basement.Types.Word256    (Word256 (Word256))
 import qualified Basement.Types.Word256    as Basement (quot, rem)
+import           Data.Aeson                (ToJSON(..))
 import           Data.Bits                 (Bits (testBit), (.&.))
 import           Data.Proxy                (Proxy (..))
 import           Data.Serialize            (Get, Putter, Serialize (get, put))
@@ -90,6 +91,9 @@ instance (n <= 256) => AbiGet (UIntN n) where
 instance (n <= 256) => AbiPut (UIntN n) where
     abiPut = putWord256 . unUIntN
 
+instance (KnownNat n, n <= 256) => ToJSON (UIntN n) where
+  toJSON = toJSON . toInteger
+
 -- | Signed integer with fixed length in bits.
 newtype IntN (n :: Nat) = IntN { unIntN :: Word256 }
     deriving (Eq, Ord, Enum, Bits, Generic)
@@ -130,6 +134,9 @@ instance (n <= 256) => AbiGet (IntN n) where
 instance (n <= 256) => AbiPut (IntN n) where
     abiPut = putWord256 . unIntN
 
+instance (KnownNat n, n <= 256) => ToJSON (IntN n) where
+  toJSON = toJSON . toInteger
+
 -- | Serialize 256 bit unsigned integer.
 putWord256 :: Putter Word256
 putWord256 (Word256 a3 a2 a1 a0) =