Clojurians Log v2

(-> server ^QueuedThreadPool .getThreadPool .isDaemon)

(-> server ^QueuedThreadPool (.getThreadPool) .isDaemon)

This is what hiredman was referring to, and what the macroexpansion noisesmith showed happens.

https://gist.github.com/darkleaf/d5f8869b47a1a2688b05e154cbf40c42#file-core-clj-L17

If server is hinted then the intermediate bits may not need hinting

.. is also something I never use

Good call! Looks like they do in this case, though. 😞

It predates -> and ->> if I recall, and the arrows are better it basically every way

(-> foo ^Bar (whatever) (.someBarMethod))

Yeah, I hear ya. I'm trying to make a change that changes as little as possible here, though.

Thanks! I tried going with the arrow, but I didn't realize you need the parens in around the first form I'm threading through (whatever) .

So (-> server ^QueuedThreadPool (.getThreadPool) .isDaemon) works, but (-> server ^QueuedThreadPool .getThreadPool .isDaemon) reflects.

correct me if I am wrong, but that's because the metadata can't attach to a method but can attach to a list with a method inside?

(ins)user=> (binding [*print-meta* true]
               (prn
                (macroexpand
                 '(-> server ^QueuedThreadPool .getThreadPool .isDaemon))))
(. (^QueuedThreadPool .getThreadPool server) isDaemon)
nil
(ins)user=> (binding [*print-meta* true]
               (prn
                (macroexpand
                 '(-> server ^QueuedThreadPool (.getThreadPool) .isDaemon))))
(. ^{:line 4, :column 30, :tag QueuedThreadPool} (.getThreadPool server) isDaemon)
nil

well, it isn't a method, it is a symbol

I mean that after reading, there's nothing for the metadata to stay on? I am probably misunderstanding

but it has to do with either how the macro or the compiler copy or list manipulation functions copy metadata around

I think the source metadata is a clue

thanks

and many how (.foo bar) gets rewritten as (. bar (foo)), but I forget if the compiler still bothers to desugar that

I tend to do:

(-> (PutObjectRequest/builder)
  (PutObjectRequest$Builder/.bucket bucket)
  (PutObjectRequest$Builder/.key key))

(-> something (.foo) (.bar) (.zoo))

(-> something (Hello/.foo) (World/.bar) (Monkey/.zoo))

Yes, I do that as well, but I specified "prior to Clojure 1.12" in my original question.

Yes you did, sorry.

No worries, it's good to point that out for the benefit of future generations, if nothing else. 🙂

OK, if I were on a Clojure version prior to 1.12, I would first upgrade to 1.12, and then do the above. Prior to 1.12, I used a lot of wrapper functions and let s to get around this. Eg., I would gather up some part of the chain into a function, and type hint the function like:

(defn get-monkey-zoo
 ^Zoo [^Something x] …)

This was for Ring, so upgrading to 1.12 was not an option, but yes, if it is an option, definitely would also do that first.