+ (Left e1, rest) = case runParser p2 i of
+ (Left e2, rest) = (Left $ e1+e2, rest)
+ (Right r, rest) = (Right r, rest)
+
+//Try the parser, if it fails decorate the error with Expected of the given String and position
+(<?>) :: (Parser a b) (String, Int) -> Parser a b
+(<?>) p (e,pos) = Parser \i -> case runParser p i of
+ (Left e1, rest) = (Left $ e1 + Unexpected e pos, rest)
+ (Right r, rest) = (Right r, rest)