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31 lines
897 B
31 lines
897 B
7 years ago
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{-# LANGUAGE OverloadedStrings #-}
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{-# LANGUAGE QuasiQuotes #-}
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module NumberOrString 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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import Data.Scientific (floatingOrInteger)
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data NumberOrString = Numba Integer| Stringy Text deriving (Eq, Show)
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instance FromJSON NumberOrString where
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parseJSON (Number i) =
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case floatingOrInteger i of
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(Left _) -> fail "Must be integral number"
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(Right integer) -> return $ Numba integer
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parseJSON (String s) = return $ Stringy s
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parseJSON _ = fail "NumberOrString must be number or string"
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dec :: ByteString -> Maybe NumberOrString
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dec = decode
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eitherDec :: ByteString -> Either String NumberOrString
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eitherDec = eitherDecode
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main = do
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print $ dec "blah"
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print $ eitherDec "blah"
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