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53 lines
1.3 KiB
53 lines
1.3 KiB
7 years ago
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{-# LANGUAGE OverloadedStrings #-}
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{-# LANGUAGE QuasiQuotes #-}
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module Marshalling where
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import Control.Applicative
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import Data.Aeson
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import Data.ByteString.Lazy (ByteString)
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import qualified Data.Text as T
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import Data.Text (Text)
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import Text.RawString.QQ
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sectionJson :: ByteString
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sectionJson = [r|
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{ "section": {"host": "wikipedia.org"},
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"whatisit": {"red": "intoothandclaw"}
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}
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|]
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data TestData = TestData { section :: Host, what :: Color } deriving (Eq, Show)
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instance FromJSON TestData where
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parseJSON (Object v) =
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TestData <$> v .: "section"
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<*> v .: "whatisit"
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parseJSON _ = fail "Expected an object for TestData"
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newtype Host = Host String deriving (Eq, Show)
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instance FromJSON Host where
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parseJSON (Object v) =
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Host <$> v .: "host"
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parseJSON _ = fail "Expected an object for Host"
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type Annotation = String
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data Color = Red Annotation
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| Blue Annotation
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| Yellow Annotation
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deriving (Eq, Show)
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instance FromJSON Color where
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parseJSON (Object v) =
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(Red <$> v .: "red") <|>
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(Blue <$> v .: "blue") <|>
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(Yellow <$> v .: "yellow")
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parseJSON _ = fail "Expected an object for Color"
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main :: IO ()
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main = do
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let d :: Maybe TestData
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d = decode sectionJson
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print d
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