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46 lines
1.3 KiB
Haskell
46 lines
1.3 KiB
Haskell
-- |
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-- Module : Text.Megaparsec.String
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-- Copyright : © 2015 Megaparsec contributors
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-- © 2007 Paolo Martini
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-- License : BSD3
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--
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-- Maintainer : Mark Karpov <markkarpov@opmbx.org>
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-- Stability : experimental
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-- Portability : portable
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--
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-- Make Strings an instance of 'Stream' with 'Char' token type.
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module Text.Megaparsec.String
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( Parser
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, GenParser
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, parseFromFile )
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where
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import Text.Megaparsec.Error
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import Text.Megaparsec.Prim
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-- | Different modules corresponding to various types of streams (@String@,
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-- @Text@, @ByteString@) define it differently, so user can use \"abstract\"
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-- @Parser@ type and easily change it by importing different \"type
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-- modules\".
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type Parser = Parsec String ()
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-- | @GenParser@ is similar to @Parser@ but it's parametrized over user
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-- state type.
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type GenParser tok st = Parsec [tok] st
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-- | @parseFromFile p filePath@ runs a string parser @p@ on the
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-- input read from @filePath@ using 'Prelude.readFile'. Returns either a
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-- 'ParseError' ('Left') or a value of type @a@ ('Right').
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--
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-- > main = do
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-- > result <- parseFromFile numbers "digits.txt"
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-- > case result of
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-- > Left err -> print err
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-- > Right xs -> print (sum xs)
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parseFromFile :: Parser a -> String -> IO (Either ParseError a)
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parseFromFile p fname = runParser p () fname <$> readFile fname
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