On Sat, Nov 15, 2008 at 3:59 PM, Ariel J. Birnbaum wrote:

Hi all!

When working with Applicative, I often find myself defining and using this operator:

(<%>) :: (Applicative f) => f (a -> b) -> a -> f b f <%> x = f <*> pure x

Yeah, me too. The syntax chosen for applicative does not encode all the information about the lifting of each side. For example, as far as I can tell, <$> is appropriate for both this and for fmap. So I think <%> is a fine name (I often use % as the application operator when I'm encoding lambda calculus). Luke

On Sun, Nov 16, 2008 at 12:59:09AM +0200, Ariel J. Birnbaum wrote:

When working with Applicative, I often find myself defining and using this operator:

(<%>) :: (Applicative f) => f (a -> b) -> a -> f b f <%> x = f <*> pure x

and always keep wondering whether it is already known by another name.

f <%> x = fmap ($ x) f will be more efficient in many cases. As for the name, <$$> would be analogous with the existing <**>.