+{-# LANGUAGE
+ UnicodeSyntax
+ #-}
+-- |A set of auxiliary parser utilities.
module Network.HTTP.Lucu.Parser
- ( Parser(..)
- , parse -- Parser a -> ByteString -> Maybe (a, ByteString)
- , anyChar -- Parser Char
- , satisfy -- (Char -> Bool) -> Parser Char
- , char -- Char -> Parser Char
- , string -- String -> Parser String
- , (<|>) -- Parser a -> Parser a -> Parser a
- , oneOf -- [Char] -> Parser Char
- , digit -- Parser Char
- , notFollowedBy -- Parser a -> Parser ()
- , many -- Parser a -> Parser [a]
- , many1 -- Parser a -> Parser [a]
- , manyTill -- Parser a -> Parser end -> Parser [a]
- , many1Till -- Parser a -> Parser end -> Parser [a]
- , option -- a -> Parser a -> Parser a
- , sp -- Parser Char
- , ht -- Parser Char
- , crlf -- Parser String
+ ( atMost
+ , finishOff
+ , skipManyTill
+ , skipWhile1
+ , skipSpace1
+ , isAlphaNum
)
where
-
-import Control.Monad
-import Control.Monad.State
-import qualified Data.ByteString.Lazy.Char8 as B
-import Data.ByteString.Lazy.Char8 (ByteString)
-
-data Parser a = Parser {
- runParser :: State ByteString (Maybe a)
- }
-
-
--- (>>=) :: Parser a -> (a -> Parser b) -> Parser b
-instance Monad Parser where
- p >>= f = Parser $ do saved <- get -- 失敗した時の爲に状態を保存
- result <- runParser p
- case result of
- Just a -> runParser (f a)
- Nothing -> do put saved -- 状態を復歸
- return Nothing
- return = Parser . return . Just
- fail _ = Parser $ return Nothing
-
-
-parse :: Parser a -> ByteString -> Maybe (a, ByteString)
-parse p input = case runState (runParser p) input of
- (Just a , input') -> Just (a, input')
- (Nothing, _ ) -> Nothing
-
-
-anyChar :: Parser Char
-anyChar = Parser $ do input <- get
- if B.null input then
- return Nothing
- else
- do let c = B.head input
- put (B.tail input)
- return (Just c)
-
-
-satisfy :: (Char -> Bool) -> Parser Char
-satisfy f = do c <- anyChar
- unless (f c) (fail "")
- return c
-
-
-char :: Char -> Parser Char
-char c = satisfy (== c)
-
-
-string :: String -> Parser String
-string str = do mapM_ char str
- return str
-
-
-infixr 0 <|>
-
-(<|>) :: Parser a -> Parser a -> Parser a
-f <|> g = Parser $ do saved <- get -- 状態を保存
- result <- runParser f
- case result of
- Just a -> return (Just a)
- Nothing -> do put saved -- 状態を復歸
- runParser g
-
-
-oneOf :: [Char] -> Parser Char
-oneOf = foldl (<|>) (fail "") . map char
-
-
-notFollowedBy :: Parser a -> Parser ()
-notFollowedBy p = p >>= fail "" <|> return ()
-
-
-digit :: Parser Char
-digit = oneOf "0123456789"
-
-
-many :: Parser a -> Parser [a]
-many p = do x <- p
- xs <- many p
- return (x:xs)
- <|>
- return []
-
-
-many1 :: Parser a -> Parser [a]
-many1 p = do ret <- many p
- case ret of
- [] -> fail ""
- xs -> return xs
-
-
-manyTill :: Parser a -> Parser end -> Parser [a]
-manyTill p end = many $ do x <- p
- end
- return x
-
-
-many1Till :: Parser a -> Parser end -> Parser [a]
-many1Till p end = many1 $ do x <- p
- end
- return x
-
-
-option :: a -> Parser a -> Parser a
-option def p = p <|> return def
-
-
-sp :: Parser Char
-sp = char ' '
-
-
-ht :: Parser Char
-ht = char '\t'
-
-
-crlf :: Parser String
-crlf = string "\x0d\x0a"
+import Control.Applicative
+import Control.Applicative.Unicode
+import Control.Monad.Unicode
+import Data.Attoparsec.Char8
+import Prelude.Unicode
+
+-- |@'atMost' n v@ is like @'P.many' v@ but accumulates @v@ at most
+-- @n@ times.
+atMost ∷ Alternative f ⇒ Int → f α → f [α]
+{-# INLINEABLE atMost #-}
+atMost 0 _ = pure []
+atMost n v = ( (:) <$> v ⊛ atMost (n-1) v )
+ <|>
+ pure []
+
+-- |@'finishOff' p@ is equivalent to @p '>>=' \\a -> 'endOfInput' '>>'
+-- 'return' a@.
+finishOff ∷ Parser α → Parser α
+{-# INLINE finishOff #-}
+finishOff = ((endOfInput *>) ∘ return =≪)
+
+-- |Similar to 'manyTill' but discards the result.
+skipManyTill ∷ Alternative f ⇒ f α → f β → f ()
+{-# INLINEABLE skipManyTill #-}
+skipManyTill p end = go
+ where
+ go = (end *> pure ()) <|> (p *> go)
+
+-- |Similar to 'skipWhile' but consumes at least one character.
+skipWhile1 ∷ (Char → Bool) → Parser ()
+{-# INLINE skipWhile1 #-}
+skipWhile1 p = takeWhile1 p *> pure ()
+
+-- |Similar to 'skipSpace' but consumes at least one whitespace.
+skipSpace1 ∷ Parser ()
+{-# INLINE skipSpace1 #-}
+skipSpace1 = skipMany1 space
+
+-- |@'isAlphaNum' c@ returns 'True' iff @'isDigit' c ||
+-- 'isAlpha_ascii' c@.
+isAlphaNum ∷ Char → Bool
+{-# INLINE isAlphaNum #-}
+isAlphaNum c = isDigit c ∨ isAlpha_ascii c