X-Git-Url: http://git.cielonegro.org/gitweb.cgi?a=blobdiff_plain;f=Network%2FHTTP%2FLucu%2FParser.hs;h=90c52696fbb4293e95849e5335758d7a255913bd;hb=1196f43ecedbb123515065f0440844864af906fb;hp=4c44f0be3e7dfa75d74b0af3bd05260d3f5b47e9;hpb=0b4db5681e3b0b27357a87316822ea3671f8c174;p=Lucu.git

diff --git a/Network/HTTP/Lucu/Parser.hs b/Network/HTTP/Lucu/Parser.hs
index 4c44f0b..90c5269 100644
--- a/Network/HTTP/Lucu/Parser.hs
+++ b/Network/HTTP/Lucu/Parser.hs
@@ -1,7 +1,8 @@
--- |Yet another parser combinator. This is mostly a subset of Parsec
--- but there are some differences:
+-- |Yet another parser combinator. This is mostly a subset of
+-- "Text.ParserCombinators.Parsec" but there are some differences:
 --
--- * This parser works on ByteString instead of String.
+-- * This parser works on 'Data.ByteString.Base.LazyByteString'
+--   instead of 'Prelude.String'.
 --
 -- * Backtracking is the only possible behavior so there is no \"try\"
 --   action.
@@ -20,6 +21,8 @@ module Network.HTTP.Lucu.Parser
     ( Parser
     , ParserResult(..)
 
+    , failP
+
     , parse
     , parseStr
 
@@ -30,14 +33,13 @@ module Network.HTTP.Lucu.Parser
     , char
     , string
     , (<|>)
+    , choice
     , oneOf
     , digit
     , hexDigit
     , notFollowedBy
     , many
     , many1
-    , manyTill
-    , many1Till
     , count
     , option
     , sepBy
@@ -49,21 +51,25 @@ module Network.HTTP.Lucu.Parser
     )
     where
 
-import           Control.Monad
-import           Control.Monad.State
-import qualified Data.ByteString.Lazy.Char8 as B
-import           Data.ByteString.Lazy.Char8 (ByteString)
+import           Control.Monad.State.Strict
+import qualified Data.ByteString.Lazy as Lazy (ByteString)
+import qualified Data.ByteString.Lazy.Char8 as B hiding (ByteString)
 
--- |@Parser a@ is obviously a parser which parses and returns @a@.
-data Parser a = Parser {
+-- |@'Parser' a@ is obviously a parser which parses and returns @a@.
+newtype Parser a = Parser {
       runParser :: State ParserState (ParserResult a)
     }
 
-type ParserState = (ByteString, IsEOFFatal)
 
-type IsEOFFatal = Bool
+data ParserState
+    = PST {
+        pstInput      :: Lazy.ByteString
+      , pstIsEOFFatal :: !Bool
+      }
+    deriving (Eq, Show)
+
 
-data ParserResult a = Success a
+data ParserResult a = Success !a
                     | IllegalInput -- 受理出來ない入力があった
                     | ReachedEOF   -- 限界を越えて讀まうとした
                       deriving (Eq, Show)
@@ -71,72 +77,86 @@ data ParserResult a = Success a
 
 --  (>>=) :: Parser a -> (a -> Parser b) -> Parser b
 instance Monad Parser where
-    p >>= f = Parser $ do saved@(_, isEOFFatal) <- get -- 失敗した時の爲に状態を保存
-                          result <- runParser p
-                          case result of
-                            Success a    -> runParser (f a)
-                            IllegalInput -> do put saved -- 状態を復歸
-                                               return IllegalInput
-                            ReachedEOF   -> do unless isEOFFatal
-                                                          $ put saved -- 状態を復歸
-                                               return ReachedEOF
-    return = Parser . return . Success
-    fail _ = Parser $ return IllegalInput
-
--- |@'parse' p bstr@ parses @bstr@ with @p@ and returns @(result,
--- remaining)@.
-parse :: Parser a -> ByteString -> (ParserResult a, ByteString)
-parse p input = let (result, (input', _)) = runState (runParser p) (input, True)
-                in
-                  (result, input')
+    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
+                             Success a    -> runParser (f a)
+                             IllegalInput -> do put saved -- 状態を復歸
+                                                return IllegalInput
+                             ReachedEOF   -> do put saved -- 状態を復歸
+                                                return ReachedEOF
+    return x = x `seq` Parser $! return $! Success x
+    fail _   = Parser $! return $! IllegalInput
+
+-- |@'failP'@ is just a synonym for @'Prelude.fail'
+-- 'Prelude.undefined'@.
+failP :: Parser a
+failP = fail undefined
+
+-- |@'parse' p bstr@ parses @bstr@ with @p@ and returns @(# result,
+-- remaining #)@.
+parse :: Parser a -> Lazy.ByteString -> (# ParserResult a, Lazy.ByteString #)
+parse p input -- input は lazy である必要有り。
+    = p `seq`
+      let (result, state') = runState (runParser p) (PST input True)
+      in
+        result `seq` (# result, pstInput state' #) -- pstInput state' も lazy である必要有り。
 
 -- |@'parseStr' p str@ packs @str@ and parses it.
-parseStr :: Parser a -> String -> (ParserResult a, ByteString)
-parseStr p input = parse p $ B.pack input
+parseStr :: Parser a -> String -> (# ParserResult a, Lazy.ByteString #)
+parseStr p input
+    = p `seq` -- input は lazy である必要有り。
+      parse p (B.pack input)
 
 
 anyChar :: Parser Char
-anyChar = Parser $ do (input, isEOFFatal) <- get
-                      if B.null input then
-                          return ReachedEOF
-                        else
-                          do let c = B.head input
-                             put (B.tail input, isEOFFatal)
-                             return (Success c)
+anyChar = Parser $!
+          do state@(PST input _) <- get
+             if B.null input then
+                 return ReachedEOF
+               else
+                 do put $! state { pstInput = B.tail input }
+                    return (Success $! B.head input)
 
 
 eof :: Parser ()
-eof = Parser $ do (input, _) <- get
-                  if B.null input then
-                      return $ Success ()
-                    else
-                      return IllegalInput
+eof = Parser $!
+      do PST input _ <- get
+         if B.null input then
+             return $! Success ()
+           else
+             return IllegalInput
 
 -- |@'allowEOF' p@ makes @p@ treat reaching EOF a normal failure.
 allowEOF :: Parser a -> Parser a
-allowEOF f = Parser $ do (input, isEOFFatal) <- get
-                         put (input, False)
+allowEOF f = f `seq`
+             Parser $! do saved@(PST _ isEOFFatal) <- get
+                          put $! saved { pstIsEOFFatal = False }
 
-                         result <- runParser f
+                          result <- runParser f
                          
-                         (input', _) <- get
-                         put (input', isEOFFatal)
+                          state <- get
+                          put $! state { pstIsEOFFatal = isEOFFatal }
 
-                         return result
+                          return result
 
 
 satisfy :: (Char -> Bool) -> Parser Char
-satisfy f = do c <- anyChar
-               unless (f c) (fail "")
-               return c
+satisfy f = f `seq`
+            do c <- anyChar
+               if f $! c then
+                   return c
+                 else
+                   failP
 
 
 char :: Char -> Parser Char
-char c = satisfy (== c)
+char c = c `seq` satisfy (== c)
 
 
 string :: String -> Parser String
-string str = do mapM_ char str
+string str = str `seq`
+             do mapM_ char str
                 return str
 
 
@@ -145,25 +165,41 @@ infixr 0 <|>
 -- |This is the backtracking alternation. There is no non-backtracking
 -- equivalent.
 (<|>) :: Parser a -> Parser a -> Parser a
-f <|> g = Parser $ do saved@(_, isEOFFatal) <- get -- 状態を保存
-                      result <- runParser f
-                      case result of
-                        Success a    -> return $ Success a
-                        IllegalInput -> do put saved -- 状態を復歸
-                                           runParser g
-                        ReachedEOF   -> if isEOFFatal then
-                                            return ReachedEOF
-                                        else
-                                            do put saved
-                                               runParser g
+f <|> g
+    = f `seq` g `seq`
+      Parser $! do saved  <- get -- 状態を保存
+                   result <- runParser f
+                   case result of
+                     Success a    -> return $! Success a
+                     IllegalInput -> do put saved -- 状態を復歸
+                                        runParser g
+                     ReachedEOF   -> if pstIsEOFFatal saved then
+                                         return ReachedEOF
+                                     else
+                                         do put saved
+                                            runParser g
+
+
+choice :: [Parser a] -> Parser a
+choice = foldl (<|>) failP
 
 
 oneOf :: [Char] -> Parser Char
-oneOf = foldl (<|>) (fail "") . map char
+oneOf = foldl (<|>) failP . map char
 
 
 notFollowedBy :: Parser a -> Parser ()
-notFollowedBy p = p >>= fail "" <|> return ()
+notFollowedBy p
+    = p `seq`
+      Parser $! do saved  <- get -- 状態を保存
+                   result <- runParser p
+                   case result of
+                     Success _    -> do put saved -- 状態を復歸
+                                        return IllegalInput
+                     IllegalInput -> do put saved -- 状態を復歸
+                                        return $! Success ()
+                     ReachedEOF   -> do put saved -- 状態を復歸
+                                        return $! Success ()
 
 
 digit :: Parser Char
@@ -171,7 +207,7 @@ digit = do c <- anyChar
            if c >= '0' && c <= '9' then
                return c
              else
-               fail ""
+               failP
 
 
 hexDigit :: Parser Char
@@ -181,11 +217,12 @@ hexDigit = do c <- anyChar
                  (c >= 'A' && c <= 'F') then
                   return c
                 else
-                  fail ""
+                  failP
 
 
 many :: Parser a -> Parser [a]
-many p = do x  <- p
+many p = p `seq`
+         do x  <- p
             xs <- many p
             return (x:xs)
          <|>
@@ -193,42 +230,34 @@ many p = do x  <- p
 
 
 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
+many1 p = p `seq`
+          do x  <- p
+             xs <- many p
+             return (x:xs)
 
 
 count :: Int -> Parser a -> Parser [a]
 count 0 _ = return []
-count n p = do x  <- p
+count n p = n `seq` p `seq`
+            do x  <- p
                xs <- count (n-1) p
                return (x:xs)
 
-
+-- def may be a _|_
 option :: a -> Parser a -> Parser a
-option def p = p <|> return def
+option def p = p `seq`
+               p <|> return def
 
 
 sepBy :: Parser a -> Parser sep -> Parser [a]
-sepBy p sep = sepBy1 p sep <|> return []
+sepBy p sep = p `seq` sep `seq`
+              sepBy1 p sep <|> return []
 
 
 sepBy1 :: Parser a -> Parser sep -> Parser [a]
-sepBy1 p sep = do x  <- p
-                  xs <- many $ sep >> p
+sepBy1 p sep = p `seq` sep `seq`
+               do x  <- p
+                  xs <- many $! sep >> p
                   return (x:xs)