That's almost literally what happens. (comp (map inc) (filter even?)) when applied takes all even numbers from a collection/channel/what-have-you and adds one t

That's almost literally what happens. (comp (map inc) (filter even?)) when applied takes all even numbers from a collection/channel/what-have-you and adds one to them. Filter and map normally take a collection as their last argument, but when none are supplied, a transducer is returned instead.