@@ -173,9 +173,16 @@ notFollowedBy' p = try $ join $ do a <- try p
173173 return (return ())
174174-- (This version due to Andrew Pimlott on the Haskell mailing list.)
175175
176−-- | Parses one of a list of strings (tried in order).
176+-- | Parses one of a list of strings (tried in order).
177177oneOfStrings :: [String] -> Parsec [Char] st String
178−oneOfStrings listOfStrings = choice $ map (try . string) listOfStrings
178+oneOfStrings [] = fail "no strings"
179+oneOfStrings strs = do
180+ c <- anyChar
181+ let strs' = [xs | (x:xs) <- strs, x == c]
182+ case strs' of
183+ [] -> fail "not found"
184+ z | "" `elem` z -> return [c]
185+ | otherwise -> (c:) `fmap` oneOfStrings strs'
179186
180187-- | Parses a space or tab.
181188spaceChar :: Parsec [Char] st Char