Base.hs

module Calculator.Parser.Base where

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import Calculator.Prim.Base (Number)

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import Control.Monad (liftM2)
import Control.Applicative ((<$>))
import Text.ParserCombinators.Parsec

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parseNumber :: Parser Number
parseNumber = read <$> do
  dec <- many1 digit
  flt <- option "" (liftM2 (:) (char '.') (many1 digit))
  return $ if null flt
           then dec
           else dec ++ flt

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parseId :: Parser String
parseId = (liftM2 (:) letter (many (letter <|> digit)))

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