1 module Network.HTTP.Lucu.Parser
4 , parse -- Parser a -> ByteString -> ParserResult a
5 , anyChar -- Parser Char
6 , satisfy -- (Char -> Bool) -> Parser Char
7 , char -- Char -> Parser Char
8 , string -- String -> Parser String
9 , (<|>) -- Parser a -> Parser a -> Parser a
10 , oneOf -- [Char] -> Parser Char
11 , digit -- Parser Char
12 , notFollowedBy -- Parser a -> Parser ()
13 , many -- Parser a -> Parser [a]
14 , many1 -- Parser a -> Parser [a]
15 , manyTill -- Parser a -> Parser end -> Parser [a]
16 , many1Till -- Parser a -> Parser end -> Parser [a]
17 , option -- a -> Parser a -> Parser a
20 , crlf -- Parser String
25 import Control.Monad.State
26 import qualified Data.ByteString.Lazy.Char8 as B
27 import Data.ByteString.Lazy.Char8 (ByteString)
29 data Parser a = Parser {
30 runParser :: State ByteString (ParserResult a)
33 data ParserResult a = Success a
34 | IllegalInput -- 受理出來ない入力があった
35 | ReachedEOF -- 限界を越えて讀まうとした
38 -- (>>=) :: Parser a -> (a -> Parser b) -> Parser b
39 instance Monad Parser where
40 p >>= f = Parser $ do saved <- get -- 失敗した時の爲に状態を保存
43 Success a -> runParser (f a)
44 IllegalInput -> do put saved -- 状態を復歸
46 ReachedEOF -> return ReachedEOF
47 return = Parser . return . Success
48 fail _ = Parser $ return IllegalInput
51 parse :: Parser a -> ByteString -> (ParserResult a, ByteString)
52 parse p input = runState (runParser p) input
55 anyChar :: Parser Char
56 anyChar = Parser $ do input <- get
60 do let c = B.head input
65 satisfy :: (Char -> Bool) -> Parser Char
66 satisfy f = do c <- anyChar
67 unless (f c) (fail "")
71 char :: Char -> Parser Char
72 char c = satisfy (== c)
75 string :: String -> Parser String
76 string str = do mapM_ char str
82 (<|>) :: Parser a -> Parser a -> Parser a
83 f <|> g = Parser $ do saved <- get -- 状態を保存
86 Success a -> return $ Success a
87 IllegalInput -> do put saved -- 状態を復歸
89 ReachedEOF -> return ReachedEOF
92 oneOf :: [Char] -> Parser Char
93 oneOf = foldl (<|>) (fail "") . map char
96 notFollowedBy :: Parser a -> Parser ()
97 notFollowedBy p = p >>= fail "" <|> return ()
101 digit = oneOf "0123456789"
104 many :: Parser a -> Parser [a]
112 many1 :: Parser a -> Parser [a]
113 many1 p = do ret <- many p
119 manyTill :: Parser a -> Parser end -> Parser [a]
120 manyTill p end = many $ do x <- p
125 many1Till :: Parser a -> Parser end -> Parser [a]
126 many1Till p end = many1 $ do x <- p
131 option :: a -> Parser a -> Parser a
132 option def p = p <|> return def
143 crlf :: Parser String
144 crlf = string "\x0d\x0a"