1 module Network.HTTP.Lucu.Parser
3 , parse -- Parser a -> ByteString -> Maybe (a, ByteString)
4 , anyChar -- Parser Char
5 , satisfy -- (Char -> Bool) -> Parser Char
6 , char -- Char -> Parser Char
7 , string -- String -> Parser String
8 , (<|>) -- Parser a -> Parser a -> Parser a
9 , oneOf -- [Char] -> Parser Char
10 , digit -- Parser Char
11 , notFollowedBy -- Parser a -> Parser ()
12 , many -- Parser a -> Parser [a]
13 , many1 -- Parser a -> Parser [a]
14 , manyTill -- Parser a -> Parser end -> Parser [a]
15 , many1Till -- Parser a -> Parser end -> Parser [a]
16 , option -- a -> Parser a -> Parser a
19 , crlf -- Parser String
24 import Control.Monad.State
25 import qualified Data.ByteString.Lazy.Char8 as B
26 import Data.ByteString.Lazy.Char8 (ByteString)
28 data Parser a = Parser {
29 runParser :: State ByteString (Maybe a)
33 -- (>>=) :: Parser a -> (a -> Parser b) -> Parser b
34 instance Monad Parser where
35 p >>= f = Parser $ do saved <- get -- 失敗した時の爲に状態を保存
38 Just a -> runParser (f a)
39 Nothing -> do put saved -- 状態を復歸
41 return = Parser . return . Just
42 fail _ = Parser $ return Nothing
45 parse :: Parser a -> ByteString -> Maybe (a, ByteString)
46 parse p input = case runState (runParser p) input of
47 (Just a , input') -> Just (a, input')
48 (Nothing, _ ) -> Nothing
51 anyChar :: Parser Char
52 anyChar = Parser $ do input <- get
56 do let c = B.head input
61 satisfy :: (Char -> Bool) -> Parser Char
62 satisfy f = do c <- anyChar
63 unless (f c) (fail "")
67 char :: Char -> Parser Char
68 char c = satisfy (== c)
71 string :: String -> Parser String
72 string str = do mapM_ char str
78 (<|>) :: Parser a -> Parser a -> Parser a
79 f <|> g = Parser $ do saved <- get -- 状態を保存
82 Just a -> return (Just a)
83 Nothing -> do put saved -- 状態を復歸
87 oneOf :: [Char] -> Parser Char
88 oneOf = foldl (<|>) (fail "") . map char
91 notFollowedBy :: Parser a -> Parser ()
92 notFollowedBy p = p >>= fail "" <|> return ()
96 digit = oneOf "0123456789"
99 many :: Parser a -> Parser [a]
107 many1 :: Parser a -> Parser [a]
108 many1 p = do ret <- many p
114 manyTill :: Parser a -> Parser end -> Parser [a]
115 manyTill p end = many $ do x <- p
120 many1Till :: Parser a -> Parser end -> Parser [a]
121 many1Till p end = many1 $ do x <- p
126 option :: a -> Parser a -> Parser a
127 option def p = p <|> return def
138 crlf :: Parser String
139 crlf = string "\x0d\x0a"