On Thursday, June 4, 2015 at 12:55:23 PM UTC-4, Phillip Lord wrote: > > > I have a number of fairly nasty functions with a form that looks like > this: > > (defn default-ontology > ([f] > (dispatch f)) > ([f a] > (dispatch f a)) > ([f a b] > (dispatch f a b)) > ([f a b c] > (dispatch f a b c)) > ([f a b c d] > (dispatch f a b c d)) > ([f a b c d e] > (dispatch f a b c d e)) > ([f a b c d e fa] > (dispatch f a b c d e fa)) > ([f a b c d e fa g] > (dispatch f a b c d e fa g)) > ([f a b c d e fa g h] > (dispatch f a b c d e fa g h)) > ([f a b c d e fa g h i] > (dispatch f a b c d e fa g h i)) > ([f a b c d e fa g h i j] > (dispatch f a b c d e fa g h i j))) > > The reason for all of this is that I need to avoid the use of variadic > function calls for performance reasons -- this function gets called a > lot in my code base, and without this unwinding, I box and unbox > consistantly. > > Now, I dislike the code repetition here, and indeed have found already > found one bug in my code where I missed a variable out, something like.... > > ([f a b c d] > (dispatch f a b d)) > > which is hard to pick up on. > > I can't make the whole thing a macro because I need to pass this as a > first class function. And I can't macro each of the variadic elements > since the I'd need to return two elements at once. > > The best I have done up with so far is: > > (defn ^:private form-with-arity[n] > ;; left as an exercise for the reader > ) > > (defmacro ^:private m-default-ontology > `(defn default-ontology > ~@(map form-with-arity (range 1 10)))) > > (m-default-ontology) > > Or am I missing something more obvious? > > Phil >
Well, the example case could be replaced with (def default-ontology dispatch). :) Beyond that, you might want to consider generating such repetitive and predictably-structured functions with a custom def-something style macro, but it looks like you already are. -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
