Using the IsString instance for Parser in attoparsec is really nice, but unfortunately, you can't use it out of the box for the most common case. One would like to be able to write parsers in this style: "(" *> stuff <* ")" But the types of *> and <* are too general - there is no way for the type checker to figure out which instance of IsString to use for the discarded parameter. I suggest adding the following type-specialized variants to Data.Attoparsec.Char8: (<*.) :: Applicative f => f a -> f ByteString -> f a (<*.) = (<*) (.*>) :: Applicative f => f ByteString -> f a -> f a (.*>) = (*>) Once attoparsec-text gets its IsString instance, I would add the same thing to Data.Attoparsec.Text, with ByteString replaced by Text. I have been using those for both attoparsec and attoparsec-text, and I find them extremely useful. Thanks, Yitz