Question

I’m trying to create some dynamic code within clojure. In the function below, the idea is that the conditions for the (and) macro will be dynamically generated.

(defn matching-keys [rec match-feed keys]
  (> (count (clojure.set/select #(and (for [k keys]
                                        (= (% k) (rec k))))
                                (set match-feed)))
     0))

So if it worked!! then this code would produce an (and) something like this when passed keys of [:tag :attrs]:

(and (= (% :tag) (rec :tag))
     (= (% :attrs) (rec :attrs)))

I’ve been messing around with various `` and~` operators to try to make it work, and am now in a state of confusion. Any guidance is welcome.

Thanks,

Colin

Answer 1

You don’t need dynamically generated code for this. Changing the anonymous function to #(every? (fn [k] (= (% k) (rec k))) keys) should do what you want without generating code at runtime.

The ability to use higher-order functions means that you should hardly ever need to dynamically generate code.