module Parsers where

import Text.ParserCombinators.Parsec
import Data.Maybe (catMaybes)
import Data.Char (toUpper)
import Control.Monad (liftM)

-- Parsing functions not in Text.ParserCombinators.Parsec

-- There is also a good ine in hsemail, manyNtoM
countBetween m n p 
     | n < m     = error "First bound must be lower or equal than second bound"
     | otherwise = do
        xs <- try (count m p)
        ys <- try (count (n - m) ((option Nothing) (do
            y <- p
            return (Just y))))
        return (xs ++ catMaybes ys)

facultative p = liftM Just p <|> return Nothing

-- Case-insensitive parsers stloen from hsemail
-- Case-insensitive variant of Parsec's 'char' function.
ichar        :: Char -> CharParser st Char
ichar c       = satisfy (\x -> toUpper x == toUpper c)
-- Case-insensitive variant of Parsec's 'string' function.
istring      :: String -> CharParser st String
istring cs    = mapM ichar cs <?> cs

--
-- End of parsing functions