Data commit

Task/JSON/Haskell/json-1.hs

@@ -0,0 +1,24 @@
+{-# LANGUAGE OverloadedStrings #-}
+
+import Data.Aeson
+import Data.Attoparsec (parseOnly)
+import Data.Text
+import qualified Data.ByteString.Lazy.Char8 as B
+import qualified Data.ByteString.Char8 as S
+
+testdoc = object [
+    "foo"   .= (1 :: Int),
+    "bar"   .= ([1.3, 1.6, 1.9] :: [Double]),
+    "baz"   .= ("some string" :: Text),
+    "other" .= object [
+        "yes" .= ("sir" :: Text)
+        ]
+    ]
+
+main = do
+    let out = encode testdoc
+    B.putStrLn out
+    case parseOnly json (S.concat $ B.toChunks out) of
+        Left e -> error $ "strange error re-parsing json: " ++ (show e)
+        Right v | v /= testdoc -> error "documents not equal!"
+        Right v | otherwise    -> print v

Task/JSON/Haskell/json-2.hs

@@ -0,0 +1,16 @@
+{-# LANGUAGE TemplateHaskell, OverloadedStrings #-}
+import Data.Aeson
+import Data.Aeson.TH
+
+data Person = Person { firstName :: String
+                     , lastName  :: String
+                     , age :: Maybe Int
+                     } deriving (Show, Eq)
+
+$(deriveJSON defaultOptions ''Person)
+
+main = do
+    let test1 = "{\"firstName\":\"Bob\", \"lastName\":\"Smith\"}"
+        test2 = "{\"firstName\":\"Miles\", \"lastName\":\"Davis\", \"age\": 45}"
+    print (decode test1 :: Maybe Person)
+    print (decode test2 :: Maybe Person)

Task/JSON/Haskell/json-3.hs

@@ -0,0 +1,17 @@
+{-# LANGUAGE DeriveGeneric, OverloadedStrings #-}
+import Data.Aeson
+import GHC.Generics
+
+data Person = Person { firstName :: String
+                     , lastName  :: String
+                     , age :: Maybe Int
+                     } deriving (Show, Eq, Generic)
+
+instance FromJSON Person
+instance ToJSON Person
+
+main = do
+    let test1 = "{\"firstName\":\"Bob\", \"lastName\":\"Smith\"}"
+        test2 = "{\"firstName\":\"Miles\", \"lastName\":\"Davis\", \"age\": 45}"
+    print (decode test1 :: Maybe Person)
+    print (decode test2 :: Maybe Person)