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42 lines
742 B
42 lines
742 B
7 years ago
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{-# LANGUAGE QuasiQuotes #-}
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module AltParsing where
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import Control.Applicative
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import Text.RawString.QQ
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import Text.Trifecta
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type NumberOrString = Either Integer String
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a :: String
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a = "blah"
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b :: String
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b = "123"
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c :: String
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c = "123blah789"
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eitherOr :: String
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eitherOr = [r|
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123
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abc
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456
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def
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parseNos :: Parser NumberOrString
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parseNos = do
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skipMany (oneOf "\n")
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v <- (Left <$> integer) <|> (Right <$> some letter)
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skipMany (oneOf "\n")
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return v
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main :: IO ()
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main = do
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let p f i = parseString f mempty i
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print $ p (some letter) a
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print $ p integer b
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print $ p parseNos a
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print $ p parseNos b
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print $ p (many parseNos) c
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print $ p (some parseNos) c
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print $ p (some parseNos) eitherOr
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