self calls do not optimize - regression

Question

This is a regression of:

https://dev.clojure.org/jira/browse/CLJS-275

Answer 1

Comment made by: aralo

This issue can be solve by changing the {{defn}} macro for the "simple" case and carrying the function name over to the function:

(core/list 'def (with-meta name m) (cons `fn (cons name fdecl)))

This isn't done in clojure because of: https://dev.clojure.org/jira/browse/CLJ-809

Though I don't think that's and issue in CLJS since we don't have real vars anyways and can't redefine {{def}}s.

Answer 2

Comment made by: aralo

So the issue that the CLJ ticket has is emulated/shown below in CLJS:

`
(enable-console-print!)

(defn self-call-test
[n]
(prn "inner")
(when (pos? n)

(self-call-test (dec n))))

(let [orig self-call-test]
(set! self-call-test

    (fn outer [n]
      (pr "outer")
      (orig n))))

(self-call-test 2)

(def self-call-test2
(fn self-call-test2

   [n]
   (prn "inner")
   (when (pos? n)
     (self-call-test2 (dec n)))))

(let [orig self-call-test2]
(set! self-call-test2

    (fn outer [n]
      (pr "outer")
      (orig n))))

(self-call-test2 2)
`

Output in with no optimizations:

`
"outer"
"inner"
"outer"
"inner"
"outer"
"inner"

"outer"
"inner"
"inner"
"inner"
`

So: It does seem this would also break the current behaviour, HOWEVER, the above with advance optimizations gives this:

"outer" "inner" "inner" "inner"

for both. Given this, it seem better to not change behavior during advanced builds to avoid hard to track down production bugs for the users. Even if this is a slight deviation from CLJ behavior. Thoughts?

Answer 3

Comment made by: aralo

Any thoughts on this? I can create a patch if that this change is ok. It could matter a bit (performance wise) since a few of the very low level data structure functions are recursive.

Answer 4

Reference: https://clojure.atlassian.net/browse/CLJS-2038 (reported by aralo)