how do I get the size/length/count of an object of type [B ? (byte array)

@qqq count will work...

@jmacneal welcome!

@seancorfield :for some reason, I was trying (.count ...) instead of (count ...)

Overthinking/over-complicating things? 🙂

One of the things that still charms me, almost daily, working with Clojure, is that so often the very simplest thing I can imagine is what works!

I have done Clojure + Cuda via ClojureCuda. I have done Clojure + OpenGL via JOGL. However, I don't know how to mix the two. Does anyone have sample Clojure glue where the Cuda code writes to a VBO, which the JOGL code then picks up for rendering? I suspect this is possible, but just have not done this yet.

Is there a pretty-print version of pr-str ? I have a data map which I need to pr-str, but would like to keep that pretty formatted.

@dnaeon you can use with-out-str with pprint

@sundarj the thing is that some of keys in the map are Records, so when I do with-out-str with pprint I lose the tags for those records, so later on I cannot read them back.

If I have a legacy java jar, not on maven or whatever, and I want to use it in my clojure project (leiningen for building), what is the best way to use it?

i read somewhere it should be in the lib/ dir in my project, is that all that’s needed?

@kah0ona I generally just upload the jar to my local maven repo and then treat it like any other jar: https://stackoverflow.com/questions/4955635/how-to-add-local-jar-files-to-a-maven-project

ah ok thanks

yeah I’ll try that

Is there any practical (performance maybe?) difference between: (->> data (mapcat transform-fn) (into []) ;; which will expand to (into [] (mapcat transform-fn data)) and (into [] (mapcat transform-fn) data)

or is this just a visual preference thing

(insert obvious missing ) after (into []))

@tankthinks the second one is faster as it does not materialize the intermediate collections (https://clojure.org/reference/transducers is a good read)

that’s what I thought … yup … should have checked the docs 😃

https://clojure.org/guides/faq#transducers_vs_seqs

Hi! Have a question about reader conditionals: I want something like :nodejs to separate browser and nodejs environment. However, I can't find a way how to extend reader conditionals features set. I've tried to use something like (= :nodejs (get-in @cljs.env/*compiler* [:options :target])), but it is doesn't work in cases like :require in ns macro, for example. Is it possible to extend this feature set? any links on how to do that? thanks!

reader conditional features are not currently extensible

I see.. Thanks! Any plans on making it extensible? does it make sense at all? 🙂

Suppose I have a vector like (def myl [[[1]] [[2] [3]]]) Is there a way to partially flatten it and get [[1] [2] [3]] ?

flatten does actually too much

ah dammit apply concat might work

@zarkone I believe @thheller allows you do what you want in shadow-cljs

@andrea.crotti see also mapcat

@zarkone see also https://groups.google.com/forum/#!topic/clojure-dev/8YJJM8lJuQs

one of my favorite things is the transducer variant of mapcat is defined as stacking two transducers (comp (map f) cat)

@mkvlr thanks, will check this out now!

@ghadi yes, looks elegant 🙂

@mkvlr exactly what I was looking for, thank you!

What do you think of Clojure with rust as its target?

what is the fastest way to convert a n-elem byte-array to a n-elem float-array ? (each byte becomes a float valued 0 -> 255.0)

I have a cljc file in lein project and I have cljc test for it in the test folder Now I want to include cljc test in both clj and cljs test runners and see the results of the tests to include and run cljc test in clj test runner, I have to compile it and :aot :all doesn’t seem to work in the test folder How do I compile the cljc file in test folder ?

what makes you say you have to aot?

@hiredman basically it tries to find a .class file with the same name, so I tried :aot :all

what tries to find a .class file?

lein test certainly doesn't

I have a clj test runner which has (t/run-all-tests [cljc-namespace])

so not lein test, and t must be clojure.test?

clojure.test definitely doesn't look for class files

and I get Caused by: java.lang.ClassNotFoundException: cljc-namespace

because you aren't quoting the name

(t/run-all-tests '[cljc-namespace])

Now I get Caused by: java.lang.ClassCastException: clojure.lang.PersistentVector cannot be cast to java.util.regex.Pattern

i.e. with the quote

I think you meant to use a different function from run-all-tests

run-all-tests doesn't take a list of namespaces, it takes a regex

you likely meant to call run-tests

(which does take a list of namespaces)

clojure.test also doesn't load any namespaces, so you have to make sure the namespace is loaded before trying to run the tests in it

I tried (t/run-tests ’cljc-namespace) and it complains Caused by: java.lang.Exception: No namespace: cljc-namespace found

this is my test paths :test-paths ["test/clj" "test/cljs" "test/cljc" "test/doo"]

and it includes cljc files

the paths don't matter, because as I said, clojure.test doesn't do any code loading

have you run (require 'cljc-namespace) ?

I have

(ns test-runner
  (:require [clojure.test :as t :refer [is are deftest testing]]))

so you are not loading the cljc-namespace, so of course when you ask clojure.test to test it, it throws an error because the namespace you asked it to test doesn't exist (where exist here means exists in the clojure runtime, not exists like there is a file on disk that defines it)

you must load the definitions of tests first yourself before you can ask clojure.test to run the tests

I don't know the specifics of your situation, but it seems like you are a beginner, so some advice, don't use single segment namespaces like test-runner, instead use something like test.runner (the . is a segment separator). The reasoning for that is if you do aot compile a single segment namespace, you end up with a class in the default package which is usually considered kind of bad jvm citizenship

Thanks @hiredman for the clarification. However my namespace are in the format of x.runner, just changed it to not share the exact name I did try (require ’cljs-namespace) and I now get Caused by: java.lang.IllegalAccessError: reader-error does not exist

I have [org.clojure/tools.reader "1.2.1"] in my classpath

have you tried to load your source file previously

likely you have errors in it (syntax, using defs from other namespaces you haven't referred, etc)

you may also have a bunch of stale class files left over from when you were aot compiling, which can really trip you up

(I strongly recommend against aot compiling, the trade offs are just not worth it)

Thanks @hiredman seems a problem in my cljc test file

which is getting included

as you mentioned I didn’t had a require

now it loads the cljc test file

and fails in one of the file

@hiredman it works now

(ns x.runner
  (:require [clojure.test :as t :refer [is are deftest testing]]))
(t/run-all-tests #"xx\..*")

the root cause was that I didn’t had “test/cljc” in my :test-paths

thanks a lot for trying to help @hiredman