nicer word parser

1 files changed, 3 insertions, 6 deletions

diff --git a/parser/main.hs b/parser/main.hs
index 9840980..843f9a5 100644
--- a/parser/main.hs
+++ b/parser/main.hs
@@ -26,18 +26,12 @@ instance Monad (Parser a) where
     where g inp = case parse p inp of Just (a,b) -> parse (f a) b
                                       _          -> Nothing
 
-parse :: Parser a b -> a -> Maybe (b,a)
 parse (Parser f) inp = f inp
 
 satisfy :: (Char -> Bool) -> Parser String Char
 satisfy f = Parser g  where g (x:xs) | f x = Just (x,xs)
                             g _            = Nothing
 
-word :: String -> Parser String String
-word w = Parser g where l     = length w
-                        g inp = if take l inp == w then Just (w,drop l inp) 
-                                                   else Nothing
-
 space :: Parser String Char
 space = satisfy (==' ')
     
@@ -50,6 +44,9 @@ notChar c = satisfy (/=c)
 num :: Parser String Int
 num = read <$> some (satisfy isDigit) 
 
+word :: String -> Parser String String
+word (c:cs) = (:) <$> char c <*> word cs
+word _ = pure ""
 
 parseOp op sig = (pure (op) <* many space <*> num <* many space <* char sig <* many space <*> num )
 parseOps = (parseOp (+) '+' <|> parseOp (-) '-' <|> parseOp (*) '*' <|> parseOp (div) '/')