X-Git-Url: http://git.cielonegro.org/gitweb.cgi?a=blobdiff_plain;f=Network%2FHTTP%2FLucu%2FParser.hs;h=34953f58c9dc5de637759c671f672b02815aa59e;hb=8bdd1da1ee1f3e453dbe2bce246618e12e26d30c;hp=44cf1558584932f6f71f59609069b3da4a5fa949;hpb=83db536d11e8efb26848318ad4514b825f412460;p=Lucu.git

diff --git a/Network/HTTP/Lucu/Parser.hs b/Network/HTTP/Lucu/Parser.hs
index 44cf155..34953f5 100644
--- a/Network/HTTP/Lucu/Parser.hs
+++ b/Network/HTTP/Lucu/Parser.hs
@@ -33,11 +33,13 @@ module Network.HTTP.Lucu.Parser
     , char
     , string
     , (<|>)
+    , choice
     , oneOf
     , digit
     , hexDigit
     , notFollowedBy
     , many
+    , manyChar
     , many1
     , count
     , option
@@ -50,10 +52,13 @@ module Network.HTTP.Lucu.Parser
     )
     where
 
-import           Control.Monad.State.Strict
-import           Data.ByteString.Base (LazyByteString)
-import           Data.ByteString.Lazy ()
-import qualified Data.ByteString.Lazy.Char8 as B
+import           Control.Monad.State.Strict hiding (state)
+import qualified Data.ByteString.Lazy as Lazy (ByteString)
+import qualified Data.ByteString.Lazy.Char8 as B hiding (ByteString)
+import qualified Data.Foldable as Fold
+import           Data.Int
+import qualified Data.Sequence as Seq
+import           Data.Sequence (Seq, (|>))
 
 -- |@'Parser' a@ is obviously a parser which parses and returns @a@.
 newtype Parser a = Parser {
@@ -63,7 +68,7 @@ newtype Parser a = Parser {
 
 data ParserState
     = PST {
-        pstInput      :: LazyByteString
+        pstInput      :: Lazy.ByteString
       , pstIsEOFFatal :: !Bool
       }
     deriving (Eq, Show)
@@ -85,8 +90,11 @@ instance Monad Parser where
                                                 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
+    return !x = Parser $! return $! Success x
+    fail _    = Parser $! return $! IllegalInput
+
+instance Functor Parser where
+    fmap f p = p >>= return . f
 
 -- |@'failP'@ is just a synonym for @'Prelude.fail'
 -- 'Prelude.undefined'@.
@@ -95,18 +103,16 @@ failP = fail undefined
 
 -- |@'parse' p bstr@ parses @bstr@ with @p@ and returns @(# result,
 -- remaining #)@.
-parse :: Parser a -> LazyByteString -> (# ParserResult a, LazyByteString #)
-parse p input -- input は lazy である必要有り。
-    = p `seq`
-      let (result, state') = runState (runParser p) (PST input True)
+parse :: Parser a -> Lazy.ByteString -> (# ParserResult a, Lazy.ByteString #)
+parse !p input -- input は lazy である必要有り。
+    = 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。
+        (# 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, LazyByteString #)
-parseStr p input
-    = p `seq` -- input は lazy である必要有り。
-      parse p (B.pack input)
+parseStr :: Parser a -> String -> (# ParserResult a, Lazy.ByteString #)
+parseStr !p input -- input は lazy である必要有り。
+    = parse p (B.pack input)
 
 
 anyChar :: Parser Char
@@ -129,35 +135,48 @@ eof = Parser $!
 
 -- |@'allowEOF' p@ makes @p@ treat reaching EOF a normal failure.
 allowEOF :: Parser a -> Parser a
-allowEOF f = f `seq`
-             Parser $! do saved@(PST _ isEOFFatal) <- get
-                          put $! saved { pstIsEOFFatal = False }
+allowEOF !f
+    = Parser $! do saved@(PST _ isEOFFatal) <- get
+                   put $! saved { pstIsEOFFatal = False }
 
-                          result <- runParser f
+                   result <- runParser f
                          
-                          state <- get
-                          put $! state { pstIsEOFFatal = isEOFFatal }
+                   state <- get
+                   put $! state { pstIsEOFFatal = isEOFFatal }
 
-                          return result
+                   return result
 
 
 satisfy :: (Char -> Bool) -> Parser Char
-satisfy f = f `seq`
-            do c <- anyChar
-               if f $! c then
-                   return c
-                 else
-                   failP
+satisfy !f
+    = do c <- anyChar
+         if f c then
+             return c
+           else
+             failP
 
 
 char :: Char -> Parser Char
-char c = c `seq` satisfy (== c)
+char !c = satisfy (== c)
 
 
 string :: String -> Parser String
-string str = str `seq`
-             do mapM_ char str
-                return str
+string !str
+    = let bs  = B.pack str
+          len = B.length bs
+      in
+        Parser $!
+        do st <- get
+           let (bs', rest) = B.splitAt len $ pstInput st
+               st'         = st { pstInput = rest }
+           if B.length bs' < len then
+               return ReachedEOF
+             else
+               if bs == bs' then
+                   do put st'
+                      return $ Success str
+               else
+                   return IllegalInput
 
 
 infixr 0 <|>
@@ -165,28 +184,40 @@ infixr 0 <|>
 -- |This is the backtracking alternation. There is no non-backtracking
 -- equivalent.
 (<|>) :: Parser a -> Parser a -> Parser a
-f <|> g
-    = f `seq` g `seq`
-      Parser $! do saved <- get -- 状態を保存
+(!f) <|> (!g)
+    = 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
+                                         do put saved
+                                            return ReachedEOF
                                      else
                                          do put saved
                                             runParser g
 
 
+choice :: [Parser a] -> Parser a
+choice = foldl (<|>) failP
+
+
 oneOf :: [Char] -> Parser Char
 oneOf = foldl (<|>) failP . map char
 
 
 notFollowedBy :: Parser a -> Parser ()
-notFollowedBy p = p `seq`
-                  (p >> failP) <|> return ()
+notFollowedBy !p
+    = 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
@@ -207,45 +238,87 @@ hexDigit = do c <- anyChar
                   failP
 
 
-many :: Parser a -> Parser [a]
-many p = p `seq`
-         do x  <- p
-            xs <- many p
-            return (x:xs)
-         <|>
-         return []
+many :: forall a. Parser a -> Parser [a]
+many !p = Parser $!
+          do state <- get
+             let (# result, state' #) = many' state Seq.empty
+             put state'
+             return result
+    where
+      many' :: ParserState -> Seq a -> (# ParserResult [a], ParserState #)
+      many' !st !soFar
+          = case runState (runParser p) st of
+              (Success a,  st') -> many' st' (soFar |> a)
+              (IllegalInput, _) -> (# Success (Fold.toList soFar), st #)
+              (ReachedEOF  , _) -> if pstIsEOFFatal st then
+                                       (# ReachedEOF, st #)
+                                   else
+                                       (# Success (Fold.toList soFar), st #)
+
+manyChar :: Parser Char -> Parser Lazy.ByteString
+manyChar !p = Parser $!
+              do state <- get
+                 case scan' state 0 of
+                   Success len
+                       -> do let (bs, rest) = B.splitAt len (pstInput state)
+                                 state'     = state { pstInput = rest }
+                             put state'
+                             return $ Success bs
+                   ReachedEOF
+                       -> if pstIsEOFFatal state then
+                              return ReachedEOF
+                          else
+                              error "internal error"
+                   _   -> error "internal error"
+    where
+      scan' :: ParserState -> Int64 -> ParserResult Int64
+      scan' !st !soFar
+          = case runState (runParser p) st of
+              (Success _   , st') -> scan' st' (soFar + 1)
+              (IllegalInput, _  ) -> Success soFar
+              (ReachedEOF  , _  ) -> if pstIsEOFFatal st then
+                                         ReachedEOF
+                                     else
+                                         Success soFar
 
 
 many1 :: Parser a -> Parser [a]
-many1 p = p `seq`
-          do x  <- p
-             xs <- many p
-             return (x:xs)
+many1 !p = do x  <- p
+              xs <- many p
+              return (x:xs)
 
 
 count :: Int -> Parser a -> Parser [a]
-count 0 _ = return []
-count n p = n `seq` p `seq`
-            do x  <- p
-               xs <- count (n-1) p
-               return (x:xs)
+count !n !p = Parser $! count' n p Seq.empty
+
+-- This implementation is rather ugly but we need to make it
+-- tail-recursive to avoid stack overflow.
+count' :: Int -> Parser a -> Seq a -> State ParserState (ParserResult [a])
+count' 0  _  !soFar = return $! Success $! Fold.toList soFar
+count' !n !p !soFar = do saved  <- get
+                         result <- runParser p
+                         case result of
+                           Success a    -> count' (n-1) p (soFar |> a)
+                           IllegalInput -> do put saved
+                                              return IllegalInput
+                           ReachedEOF   -> do put saved
+                                              return ReachedEOF
+
 
 -- def may be a _|_
 option :: a -> Parser a -> Parser a
-option def p = p `seq`
-               p <|> return def
+option def !p = p <|> return def
 
 
 sepBy :: Parser a -> Parser sep -> Parser [a]
-sepBy p sep = p `seq` sep `seq`
-              sepBy1 p sep <|> return []
+sepBy !p !sep = sepBy1 p sep <|> return []
 
 
 sepBy1 :: Parser a -> Parser sep -> Parser [a]
-sepBy1 p sep = p `seq` sep `seq`
-               do x  <- p
-                  xs <- many $! sep >> p
-                  return (x:xs)
+sepBy1 !p !sep
+    = do x  <- p
+         xs <- many $! sep >> p
+         return (x:xs)
 
 
 sp :: Parser Char