What's a clean way to fail the test suite (`lein test` ) if an auxiliary thread threw an exception? I tried:

(-> (reify Thread$UncaughtExceptionHandler
      (uncaughtException [_ thread ex]
        (is false (pr-str ex))))
    (Thread/setDefaultUncaughtExceptionHandler))

Hey have anyone ever benchmarked carmine vs lettuce in clojure?

Fun fact:

(.toEpochMilli (java.time.Instant/MAX)) ;; => ArithmeticException: long overflow

I am looking to write a clojure wrapper for a REST api. Does anyone have any examples of existing clojure wrappers that they find to be truly excellent in some way?

Hi, I am using clojurescript since 5 months. I am very happy with the experience. On server side I use Elixir. I think without knowing JavaScript using ClojureScript would be very very hard. Is it same for Clojure? Without knowing any Java can I handle Clojure or I better stay in Elixir&Erlang

In a similar way Clojure and ClojureScript does not try and hide the host

thank you

I don't think you need to be an experienced Java developer to take advantage of Java libraries from Clojure. You do need to know how to find useful libraries, and read and interpret their API documentation, so you need at least some of the terminology of Java to be familiar and understood.

Same as https://elixirforum.com/t/must-i-learn-erlang-after-learning-elixir-can-i-learn-elixir-only/2069 I think

You’re able to use Erlang libraries from Elixir using native Elixir syntax quite easily, but you’ll need to learn Erlang syntax and semantics to read and understand Erlang API docs. Beyond that, I haven’t learned Erlang in full, and I haven’t had any issues using Elixir for everything. You mostly just need to know the mapping from Erlang to Elixir syntax.

I started Clojure at work with an Erlang background. Didn’t know much than that I disliked the JVM 🙂 But I totally switched. Today I love Clojure and benefit from the JVM. And you can come fairly far without having to deal too much with Java 🙂

Then I am going to give a deeper look 🙂 . I am in love with Erlang's BEAM but after getting used to lisp syntax I am missing it alot when I code in other languages.

this is eluding me this morning for some reason.. what would be preferable to (when [x (potentially-nil)] x)?

like some but for a single thing

or ? what you want to happen when it's nil?

yeah i could do or nil, seemed a little ugly though

i’ve never ever had to explicitly return nil before

what do you think?

I don't understand what you're asking for

sorry, i want to either return the value if it’s truthy or nil

also i’m only just now realizing this isn’t the beginners channel. sorry

that's no problem

some does what i want, but it works for collections

so are you specifically trying to avoid false?

yeah

(if (false? x) nil x)

is that logically what you want?

actually.. man this is silly, i’m reading from a map and so it would of course be nil if it doesn’t exist.

sorry. appreciate the help though. i need more coffee.

🙂

(inc coffee)

On Java->Clojure interop and classloaders: If the Java environment requires that a specific classloader be set before calling Clojure, does that imply that we always need a "native" Java class definition to handle this as opposed to doing something like gen-class? Or is there some way to make this work in Clojure with no Java code?

I assume this refers to your prior questions about KSQL. Because that env seems to have some classloader expectations, I'm not sure that there is any way to avoid doing something in Java. But not knowing anything about their setup, it's hard to say.

Howdy, How can I add more native threads (default 8 to my project?

threads for what?

how did you default them to 8? @contact904

core.async is by default using 8

@contact904 from https://clojure.github.io/core.async/ -

go blocks are dispatched over an internal thread pool, which defaults to 8 threads. The size of this pool can be modified using the Java system property `clojure.core.async.pool-size`.

there are cases when you want to up that, but more often if you have to up that it indicates an issue with your code

like blocking operations in go blocks

the pool size was deliberately made smaller to expose errors in using core.async that used to happen rarely during dev, then happen under load when deployed

it's better to rewrite your core.async code not to block the pooled threads

if you are just starting out with core.async you almost certainly do have places where you are doing blocking operations in go blocks

Likewise, setting the new flag seems recommendable (in :dev/:test builds, at the very least) https://github.com/clojure/core.async/commit/aca2b4caf195b668e0e5aba286345d5fa376b1fb#diff-04c6e90faac2675aa89e2176d2eec7d8R65

that's great, of course there are a lot of other ways to block, but that at least reduces the number of gotchas

it is wild to me how much demand there is for some lightweight way to make ns aliases to make namespaced keywords shorter to type

please elaborate if you don't mind

@sogaiu So there is something shorter than this:

(alias 'm  (create-ns 'ws.domain.member))

so :m/my-symbol is too long?

No, but people think :ws.domain.member/my-symbol is too long

i typically would do :wdm/my-symbol

and they want an easier way to alias ws.domain.member to m than the code I gave.

ah i see

ah good point

thanks -- i have been avoiding :: because i ran into troubles with it before

And being able to change the alias line once per namespace is less work (and less error prone) than changing every reference to a keyword with that qualifier...

:: is fine. I use it a lot with specs.

i'm not saying there is a problem with it -- i just had problems -- that's most likely my head containing the problem 🙂

yeah, I guess using namespaced keywords, I never find myself feeling constrained in some way by how many characters they are