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Diffstat (limited to 'vendor/attoparsec-0.10.4.0/Data/Attoparsec/Combinator.hs')
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diff --git a/vendor/attoparsec-0.10.4.0/Data/Attoparsec/Combinator.hs b/vendor/attoparsec-0.10.4.0/Data/Attoparsec/Combinator.hs new file mode 100644 index 00000000..cb9cee83 --- /dev/null +++ b/vendor/attoparsec-0.10.4.0/Data/Attoparsec/Combinator.hs @@ -0,0 +1,205 @@ +{-# LANGUAGE BangPatterns, CPP #-} +-- | +-- Module : Data.Attoparsec.Combinator +-- Copyright : Daan Leijen 1999-2001, Bryan O'Sullivan 2009-2010 +-- License : BSD3 +-- +-- Maintainer : bos@serpentine.com +-- Stability : experimental +-- Portability : portable +-- +-- Useful parser combinators, similar to those provided by Parsec. +module Data.Attoparsec.Combinator + ( + choice + , count + , option + , many' + , many1 + , many1' + , manyTill + , manyTill' + , sepBy + , sepBy' + , sepBy1 + , sepBy1' + , skipMany + , skipMany1 + , eitherP + ) where + +import Control.Applicative (Alternative(..), Applicative(..), empty, liftA2, + (<|>), (*>), (<$>)) +import Control.Monad (MonadPlus(..)) +#if !MIN_VERSION_base(4,2,0) +import Control.Applicative (many) +#endif + +#if __GLASGOW_HASKELL__ >= 700 +import Data.Attoparsec.Internal.Types (Parser) +import Data.ByteString (ByteString) +#endif + +-- | @choice ps@ tries to apply the actions in the list @ps@ in order, +-- until one of them succeeds. Returns the value of the succeeding +-- action. +choice :: Alternative f => [f a] -> f a +choice = foldr (<|>) empty +#if __GLASGOW_HASKELL__ >= 700 +{-# SPECIALIZE choice :: [Parser ByteString a] -> Parser ByteString a #-} +#endif + +-- | @option x p@ tries to apply action @p@. If @p@ fails without +-- consuming input, it returns the value @x@, otherwise the value +-- returned by @p@. +-- +-- > priority = option 0 (digitToInt <$> digit) +option :: Alternative f => a -> f a -> f a +option x p = p <|> pure x +#if __GLASGOW_HASKELL__ >= 700 +{-# SPECIALIZE option :: a -> Parser ByteString a -> Parser ByteString a #-} +#endif + +-- | A version of 'liftM2' that is strict in the result of its first +-- action. +liftM2' :: (Monad m) => (a -> b -> c) -> m a -> m b -> m c +liftM2' f a b = do + !x <- a + y <- b + return (f x y) +{-# INLINE liftM2' #-} + +-- | @many' p@ applies the action @p@ /zero/ or more times. Returns a +-- list of the returned values of @p@. The value returned by @p@ is +-- forced to WHNF. +-- +-- > word = many' letter +many' :: (MonadPlus m) => m a -> m [a] +many' p = many_p + where many_p = some_p `mplus` return [] + some_p = liftM2' (:) p many_p +{-# INLINE many' #-} + +-- | @many1 p@ applies the action @p@ /one/ or more times. Returns a +-- list of the returned values of @p@. +-- +-- > word = many1 letter +many1 :: Alternative f => f a -> f [a] +many1 p = liftA2 (:) p (many p) +{-# INLINE many1 #-} + +-- | @many1' p@ applies the action @p@ /one/ or more times. Returns a +-- list of the returned values of @p@. The value returned by @p@ is +-- forced to WHNF. +-- +-- > word = many1' letter +many1' :: (MonadPlus m) => m a -> m [a] +many1' p = liftM2' (:) p (many' p) +{-# INLINE many1' #-} + +-- | @sepBy p sep@ applies /zero/ or more occurrences of @p@, separated +-- by @sep@. Returns a list of the values returned by @p@. +-- +-- > commaSep p = p `sepBy` (symbol ",") +sepBy :: Alternative f => f a -> f s -> f [a] +sepBy p s = liftA2 (:) p ((s *> sepBy1 p s) <|> pure []) <|> pure [] +#if __GLASGOW_HASKELL__ >= 700 +{-# SPECIALIZE sepBy :: Parser ByteString a -> Parser ByteString s + -> Parser ByteString [a] #-} +#endif + +-- | @sepBy' p sep@ applies /zero/ or more occurrences of @p@, separated +-- by @sep@. Returns a list of the values returned by @p@. The value +-- returned by @p@ is forced to WHNF. +-- +-- > commaSep p = p `sepBy'` (symbol ",") +sepBy' :: (MonadPlus m) => m a -> m s -> m [a] +sepBy' p s = scan `mplus` return [] + where scan = liftM2' (:) p ((s >> sepBy1' p s) `mplus` return []) +#if __GLASGOW_HASKELL__ >= 700 +{-# SPECIALIZE sepBy' :: Parser ByteString a -> Parser ByteString s + -> Parser ByteString [a] #-} +#endif + +-- | @sepBy1 p sep@ applies /one/ or more occurrences of @p@, separated +-- by @sep@. Returns a list of the values returned by @p@. +-- +-- > commaSep p = p `sepBy1` (symbol ",") +sepBy1 :: Alternative f => f a -> f s -> f [a] +sepBy1 p s = scan + where scan = liftA2 (:) p ((s *> scan) <|> pure []) +#if __GLASGOW_HASKELL__ >= 700 +{-# SPECIALIZE sepBy1 :: Parser ByteString a -> Parser ByteString s + -> Parser ByteString [a] #-} +#endif + +-- | @sepBy1' p sep@ applies /one/ or more occurrences of @p@, separated +-- by @sep@. Returns a list of the values returned by @p@. The value +-- returned by @p@ is forced to WHNF. +-- +-- > commaSep p = p `sepBy1'` (symbol ",") +sepBy1' :: (MonadPlus m) => m a -> m s -> m [a] +sepBy1' p s = scan + where scan = liftM2' (:) p ((s >> scan) `mplus` return []) +#if __GLASGOW_HASKELL__ >= 700 +{-# SPECIALIZE sepBy1' :: Parser ByteString a -> Parser ByteString s + -> Parser ByteString [a] #-} +#endif + +-- | @manyTill p end@ applies action @p@ /zero/ or more times until +-- action @end@ succeeds, and returns the list of values returned by +-- @p@. This can be used to scan comments: +-- +-- > simpleComment = string "<!--" *> manyTill anyChar (try (string "-->")) +-- +-- Note the overlapping parsers @anyChar@ and @string \"<!--\"@, and +-- therefore the use of the 'try' combinator. +manyTill :: Alternative f => f a -> f b -> f [a] +manyTill p end = scan + where scan = (end *> pure []) <|> liftA2 (:) p scan +#if __GLASGOW_HASKELL__ >= 700 +{-# SPECIALIZE manyTill :: Parser ByteString a -> Parser ByteString b + -> Parser ByteString [a] #-} +#endif + +-- | @manyTill' p end@ applies action @p@ /zero/ or more times until +-- action @end@ succeeds, and returns the list of values returned by +-- @p@. This can be used to scan comments: +-- +-- > simpleComment = string "<!--" *> manyTill' anyChar (try (string "-->")) +-- +-- Note the overlapping parsers @anyChar@ and @string \"<!--\"@, and +-- therefore the use of the 'try' combinator. The value returned by @p@ +-- is forced to WHNF. +manyTill' :: (MonadPlus m) => m a -> m b -> m [a] +manyTill' p end = scan + where scan = (end >> return []) `mplus` liftM2' (:) p scan +#if __GLASGOW_HASKELL__ >= 700 +{-# SPECIALIZE manyTill' :: Parser ByteString a -> Parser ByteString b + -> Parser ByteString [a] #-} +#endif + +-- | Skip zero or more instances of an action. +skipMany :: Alternative f => f a -> f () +skipMany p = scan + where scan = (p *> scan) <|> pure () +#if __GLASGOW_HASKELL__ >= 700 +{-# SPECIALIZE skipMany :: Parser ByteString a -> Parser ByteString () #-} +#endif + +-- | Skip one or more instances of an action. +skipMany1 :: Alternative f => f a -> f () +skipMany1 p = p *> skipMany p +#if __GLASGOW_HASKELL__ >= 700 +{-# SPECIALIZE skipMany1 :: Parser ByteString a -> Parser ByteString () #-} +#endif + +-- | Apply the given action repeatedly, returning every result. +count :: Monad m => Int -> m a -> m [a] +count n p = sequence (replicate n p) +{-# INLINE count #-} + +-- | Combine two alternatives. +eitherP :: (Alternative f) => f a -> f b -> f (Either a b) +eitherP a b = (Left <$> a) <|> (Right <$> b) +{-# INLINE eitherP #-} |