Hi all,
this question may sound stupid but I've got to ask it....
given a fn like the one below, how would one make it lazy (assuming that
it can be done)?
also if it can, I'd like to make it fully-lazy (instead of
chunked-lazy)...any ideas? I remember something about restoring '1 at a
time' laziness in the 'Joy of Clojure' but I 'm not sure if I rememer
correctly and I don't have access to the book at the moment (lent it to
someone for 2 weeks!)...
(def ^:const board (vec (range 8)))
(defn bishop-moves
"Returns the logical moves for a bishop (on a 8x8 grid) given its
current position and direction."
[x y]
(run* [q]
(fresh [a b]
(membero a board)
(membero b board)
(!= a x)
(!= b y)
(project [x y a b]
(== (Math/abs ^long (- x a))
(Math/abs ^long (- y b)))
(== q [a b])))))
the reason I want to do this, believe it or not, is performance !!! why
calculate all the moves if I'm not going to consume them all?it's a
waste isn't it?
many thanks in advance...
Jim
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