Clojurians Log v2

@maxminos.1 :local-repo tells Maven (lein) where to cache dependencies that it downloads. Normally that’s the ~/.m2 folder. :repositories defines one or more named locations to go look for dependencies to download — normally you have central, clojars, but you can add more places to look, e.g., if you have a private Maven repo or you want to host dependencies on S3.

So if you want Leiningen to cache the JARs it downloads in a different place to usual, that’s :local-repo. What is your actual use case?

@seancorfield I am just trying to keep my ~/.m2 folder confined within ~/.cache/m2 , additionally, I have also set my maven localRepositories to the cache directory by the settings.xml, and i've also set BOOT_LOCAL_REPO to ~/.cache/m2/repository I'm just not sure how to check whether the directories are for m2/repository or just m2/

According to the Leiningen source, it looks like the default is ~/.m2/repository so that’s the structure it will expect in :local-repo.

(tools.deps.alpha has the same default for the Clojure CLI so at least that looks consistent)

perfect! that's what i have it set as, what about the :repositories "local"shown in the link?

should I just remove that?

If you don’t need to search any repos beyond Maven Central and Clojars, you can remove that.

That is terrible documentation BTW. It references #= which is undocumented and should not be used.

I’m pretty sure the clojure package it mentions on that page is not an official package and would conflict with the official Clojure CLI.

what should I use instead of #=?

I’m not sure what Leiningen allows for in profiles.clj. I know that you can just “escape” executable code in project.clj. You’d best ask in #leiningen if no one here knows how to put dynamic code in ~/.lein/profiles.clj — I haven’t used Leiningen for years.

(although since it is your user config file, you could just hardcode the full path without dynamic evaluation)

thanks alot! i will look into it

Why do you want to change Leiningen’s defaults?

just to keep my home folder clean, it also happens to help me understand how it works a little better and pushes me to look at whats going on behind the scenes

Oh, OK, you said above… sorry. I guess that "local" repo is so that it would look in your original home .m2/repository for anything already downloaded? That wiki page is not very helpful.

Scratching my head as to where I learned this if it’s undocumented. I know I’ve read the sources, but I thought I saw it somewhere else first

Never mind… I wrote it down in a note that I last updated in April 2012. Maybe I saw it mentioned at the 2011 Conj

has anyone kept track of attempts to make something like Pheonix Live View/LiveWire in clojure

I keep thinking it would be a great demo for loom stuff but I feel like I am missing some essential bits of design to actually make it work

I can throw up a simple demo that just uses https://github.com/juji-io/editscript with reagent, but that feels...lacking

(maybe even an actual use case for https://akka.io/)

I have a huge reducing function that operates on a sequences of maps and I want to introduce some functionality using a very small subset of data involved in the sequence of maps or the initial reduce state. The functionality could be capture pretty cleanly as a transducer. However, I cannot use a separate transducing context in the api I'm using, I can only provide a single reducing function. I keep wanting to make a "dummy" reducing function that just spits out the latest result from a transducer, and stick that in the reducing function, like this:

(let [xf (comp
           (map :val)
           (dedupe)
           (partition-all 2)
           (map #(reduce + %)))
      rf (xf (fn [acc x] x))
      states [{:val 1} {:val 2} {:val 3} {:val 4}]]
  (reduce
    (fn [acc x]
      (update acc :sum rf x))
    {:val 0}
    states))

https://github.com/prepor/liveview-clj https://github.com/tatut/ripley

I'm not sure, but if I cross my eyes a little it looks like reductions

maybe something from xforms?

anyone having experience with clojure manifold library (especially the streams) ? i was creating a kafka stream construct using the manifold streams

(defn kafka-stream
  [config topic]
  (let [output (s/stream 100)
        consumer (KafkaConsumer. (kuk/as-properties config))]
    (future
      (s/on-closed output (fn [] (.close consumer)))
      (d/loop []
        (.subscribe consumer [topic])
        (let [msgs (.poll consumer (:poll-timeout config 2000))]
          (doseq [m msgs]
            @(s/put! output m))
          (d/recur))))))

Maybe worth to look at KafkaStreams framework

@delaguardo actually we were building out a layer that allows us to have pluggable sources

Then I can recommend KafkaConnect. Used it as a pluggable source with common sink

Hey all, I'm just starting with deps.edn, and I'm trying to depend on a pom type dependency. Is this possible?

&lt;!-- <https://mvnrepository.com/artifact/com.ocadotechnology/OcavaParent> --&gt;
&lt;dependency&gt;
    &lt;groupId&gt;com.ocadotechnology&lt;/groupId&gt;
    &lt;artifactId&gt;OcavaParent&lt;/artifactId&gt;
    &lt;version&gt;10.10.14&lt;/version&gt;
    &lt;type&gt;pom&lt;/type&gt;
&lt;/dependency&gt;

It is possible.

https://clojure.org/reference/deps_and_cli#_dependencies

from those docs (my emphasis): > Local project coordinate: {:local/root "/path/to/project"} > Optional key :deps/manifest > Specifies the project manifest type > Default is to auto-detect the project type (currently either :deps or :pom) the type of the project isn't mentioned in the "maven coordinate" section above it 😞

and I have tried this too (documentation ignored)

I'm not sure where the misunderstanding is. Maven is based on POM. Maven artifacts, AFAIK, cannot be uploaded without POM files.

You need :mvn/version, not :local/root.

Or do you want to depend on a local JAR with a POM file in it?

there is a pom-only distribution method for maven; this is a "parent" project that doesn't have a jar artifact

{
:deps {
       ;; <https://mvnrepository.com/artifact/com.ocadotechnology/OcavaParent>
       com.ocadotechnology/OcavaParent {:mvn/version "10.10.14" :deps/manifest :pom}
       }

}

$ clj
Error building classpath. Could not find artifact com.ocadotechnology:OcavaParent:jar:10.10.14 in central (<https://repo1.maven.org/maven2/>)

Ah, apologies - I didn't realize it had that <typ> . Almost never see it. No, it's not supported. You have to list all required dependencies manually.

Grrr... frustrating because the authors have already done that! Oh well, I think I might try and do this locally, not using a remote mvn.

If you really need all of the dependencies from that pom - why is it a problem to just list them out explicitly in your deps.edn?

For context, here's where Alex Miller mentions that it's not supported: https://clojurians-log.clojureverse.org/tools-deps/2020-07-29

thanks for the reference.

Regards the previous question... I think it's a case of not duplicating effort.

It's also the case of implicit vs explicit. :) IMO, and Alex seems to have the same opinion, if you depend on something, that exact dependency should be in deps.edn. And not something else that also depends on it. But opinions can be different, of course.

I get that... I've watched Alex speaking about it. I'll be depending on only that library (for now); so I intend that it is that library that manages its dependencies (even if it is through the sub-wonderful maven strategy). I actually feel that I'm not entitled to make those choices for the library. Of course when I need one of those dependencies explicitly... then I'll be explicit.

@tim595 Oh, I just noticed that Ocava deals with simulations, and I recently became interested in the general topic of simulations, with the inline towards biological processes. Do you maybe have any recommendations in literature, tools, or something else for a beginner in the area?

As far as I know, Ocava is concerned with Discrete Event Simulations; I'm not sure if the documentation and sample code in that project gives you a good introduction. From the readme: > Ocava was created by https://www.ocadotechnology.com/'s Simulation Team after they successfully implemented a simulation and testing framework in order to test a radical proof of concept fulfilment warehouse proposal. I can vouch for it being a solid tool/library to base a Java product on. I want to see if I can use it for “stateless” simulations (value-based or even data-driven clojurey goodness). Our current product is stateful, and I don’t think it has to be

except for the bits that have to be 😉

Gotcha. Thanks!

IIRC there's a reference at the bottom of the wikipedia page for DES, titled along the lines of "simulation for beginners"

sorry: https://en.wikipedia.org/wiki/Traffic_simulation • Hollander, Yaron (2016). https://www.bookdepository.com/Transport-Modelling-for-Complete-Beginner-Yaron-Hollander/9780995662414. CTthink!.

Not DES... but related-ish

Oh, nice! Will add it to the list.

https://clojure.atlassian.net/browse/CLJ-2065

running into this in the wild

(ns ssr
  (:require
   [cognitect.transit :as transit]
   [editscript.core :as editscript]
   [editscript.edit :as edit]
   [hiccup.core :as hiccup]))

(def current-state (atom [:div]))

(println (type @current-state))

(defn render
  ([]
   (hiccup/html @current-state))
  ([new]
   (hiccup/html
    (swap! current-state
           (fn [html-1]
             (let [diff (editscript/diff html-1 new)]
               (editscript/patch html-1 diff)))))))

(render [:div "b"])
(println (type @current-state))
(render [:div "c"])
(println (type @current-state))

clojure.lang.PersistentVector
clojure.lang.APersistentVector$SubVector
Syntax error (IllegalArgumentException) compiling at (src/clj/ssr.clj:24:1).
No implementation of method: :kv-reduce of protocol: #'clojure.core.protocols/IKVReduce found for class: clojure.lang.APersistentVector$SubVector

i see the workaround so this won't hard block me, but still frustrating

You can vote here https://ask.clojure.org/index.php/3319/reduce-kv-fails-on-subvec?show=3319#q3319

voted

I've been writing functions that "pair/tuple" matches so that i can work on the combination. For example finding a match with an element in a list and returning [element match]. I could write a (tuple-match match-fn element collection) I suppose to simplify this process, but just wondering if there's already something idiomatic.

if you already have element in scope, is there any reason not to

[element (first (filter (partial match-fn element)) coll)]

or

(if-let [match (first (filter (partial match-fn element) coll))]
  [element match])

(some (fn [element] (when (condition? element match) [element match])) coll)

(if-let [match (some (partial match-fn element) coll)]
  [element match])

🙂

good suggestions. i think part of the trick for me is to learn more verbs. I forget "keep" instead of (remove nil? (map... )) some instead of (first (filter...

Is it possible to make lein uberjar aot compilation behave more like a simple (compile 'foo.bar) instead of that it iterates over a series of namespaces? that iterating causes some weird edge cases sometimes I think

"yeah, just use deps.edn", at some point yes, but not right now for this project

clojure.lang.Compile is a Java class in Clojure that basically does that

it's actually used by the Clojure build to compile Clojure itself and I don't honestly know if I'd consider it part of the "public API" of Clojure, but it does exist

well, I mean, when I run lein uberjar it says:

Compiling sci.addons
Compiling sci.addons.future
Compiling sci.core

it's a main that takes a list of namespaces to compile

perhaps it's just :aot :all -> :aot [sci.impl.main] ?

^^ I think that works too

I think I have a different problem. I get:

Caused by: java.lang.LinkageError: loader clojure.lang.DynamicClassLoader @498b697 attempted duplicate class definition for sci.impl.namespaces$copy_var. (sci.impl.namespaces$copy_var is in unnamed module of loader clojure.lang.DynamicClassLoader @498b697, parent loader clojure.lang.DynamicClassLoader @77978658)

well, I'll rewrite it.

fixed

the compilation thing caused issues in some other context, but the :all -> [sym] works well, so I also changed this

is one of the edge cases you mentioned the issue where records/protocols can become redefined mid-compilation?

That’s really the main one

wish i’d known the answer was this easy two years ago, lol. would have saved me a lot of heartbreak and work

is there a common scenario that causes this? I'm not sure I follow the specifics

https://clojure.atlassian.net/browse/CLJ-1544

@nbtheduke I have seen some weird segfaults or "no offset for this method" / "should not reach here" exceptions with this using GraalVM

could be related to the record/protocol stuff

that seems unlikely?

you typically see this problem during compilation due to the in memory classes. not sure how it would be possible to see post-compilation in something like graal

@alexmiller I'm not sure either, but I've seen this in multiple projects where the way lein compiles with :aot :all gives weird issues which was solved by simplifying that compilation using just one top namespace

I've seen it in aot compilation, just don't understand how that could impact graal

me neither, except that graal uses the AOT-ed bytecode and maybe that didn't work with the JVM either, it happened now and then in CI, randomly

if the compile succeeds, you have not encountered this issue (it's really a problem in the runtime classloader during compilation)

at least, as far as I understand it

ok, then it was something else, but I just know that getting rid of the obsolete compiles fixed it

at least, the problem didn't occur again. fixed is maybe too strong ;)

a lot of projects have issues with how their namespaces are setup such that :aot :all can result in things like defprotocols and defrecords being compiled multiple times

lein's behavior with :aot :all is just kind of really bad, it really wants to believe it can compile each namespace one at a time, when of course that is not how aot compilation works

and at least at one point the order in which :aot :all compiles namespaces was not fixed, so on different oses, different versions of java, etc, you might end up compiling in a different order, where things happened to work one way but not in another

I am following the modern-cljs tutorial (https://github.com/magomimmo/modern-cljs/), and still on the first one, but for some reason when I boot cljs target and open the index.html of the target, it gives me this error in the console: Uncaught Error: Undefined nameToPath for modern_cljs.core instead of a "Hello, world"

That hasn’t been updated in three years and a lot has changed in the ClojureScript world. Shadow_cljs and Figwheel Main are the two dominant cljs solutions these days I think?

(also Boot is not very widely used and I don’t think it’s getting much maintenance these days — I opened an important issue on boot-clj/boot-new months ago and have had zero response, even with repeated nudges).

that's really unfortunate, do you have any other resources that might be well suited for me to learn web development using ClojureScript? I have poked at shadow-cljs a little to make a todo-list with reagent but didn't get very far and got a little confused when I tried to add on to it