Question to date and time data: is clj-time still the recommended lib for this? There's conflicting information on the interwebs about what to use. Apparently Java has improved a lot and it's now recommended to use java.time directly?

I'm one of the maintainers of clj-time: please don't use it -- either use Java Time directly via interop, or one of the wrappers recommended in the clj-time readme.

https://github.com/dm3/clojure.java-time or https://github.com/henryw374/cljc.java-time or https://github.com/juxt/tick

lol, you need to make that note at the top even bolder and bigger Sean 😛 and red! maybe some <blink>

@seancorfield thanks. I'll look into clojure.java-time then. I assume I can extract day, month, year etc from a value?

I'll change the wording from "consider using" to "please use" perhaps.

@bfabry yeah - perhaps in RED 🙂. Stackoverflow is full with old answers from 7 years ago. nothing new though.

obviously not current anymore.

the Clojure Cookbook also recommends clj-time 😄

ah yes SO is particularly vulnerable to bit-rot. once that answer is ticked as accepted it probably will never change

Yeah, a lot of tutorials out there refer to clj-time -- I really don't know why it was so popular. Joda Time was already an immutable, value-based time library. clj-time really only adds a bit of syntactic sugar.

Sugar tastes good.

@seancorfield Thanks for the help. I now can parse "2020-0430T20:27:56Z" :_)

why does the first expression works but not the second? (= 2020 (t/as (t/zoned-date-time "2020-04-30T20:29:00Z") :year)) (= (list 2020 4) (t/as (t/zoned-date-time "2020-04-30T20:29:00Z") :year :day-of-month))

What is t?

java-time

from my ns (:require [java-time :as t])

Day of month is 30, not 4.

user=> (t/as (t/zoned-date-time "2020-04-30T20:29:00Z") :year :month-of-year :day-of-month)
(2020 4 30)
user=>

I'd like to filter all datetime value of a specific date. I thought I'd extract year, month and day and then compare two lists, no?

oh, I see what you mean.

but the compare fails anyway

ah, please disregard my last message - error between the ears

Using Java Time directly is just as easy:

user=> (def year-month (juxt #(.getYear %) #(.getMonthValue %)))
#'user/year-month
user=> (year-month (java.time.ZonedDateTime/parse "2020-04-30T20:27:56Z"))
[2020 4]
user=>

Or if you want the day as well

user=> (def year-month-day (juxt #(.getYear %) #(.getMonthValue %) #(.getDayOfMonth %)))
#'user/year-month-day
user=> (year-month-day (java.time.ZonedDateTime/parse "2020-04-30T20:27:56Z"))
[2020 4 30]
user=>

There are plenty of good reasons for not bothering with a simple wrapper, and just using interop.

Unless you want to write platform-independent code, in which case cljc.java-time or juxt/tick could be used.

“platform-independent dates” https://knowyourmeme.com/memes/%E0%B2%A0_%E0%B2%A0-look-of-disapproval

Yeah, well, some people seem to think such code is worthwhile. I don't do cljs so I don't care 🙂

Now that I think about it, it’s odd that I feel that way. In theory, they’re like letters or numbers. Their properties are derived from real life. But, if we’re honest, I’m pretty sure dates are a damn mess in every ecosystem.

Even in a single ecosystem…. good lord java has 3 built-in competing date/time libs. And that doesn’t even include JodaTime!

they're not really "competing". but yeah time is hard. can't wait till we have to deal with vehicles that travel at an appreciable fraction of the speed of light someday (if it ever happens)

Oh I agree, dates are the worst. We've been doing Clojure for a decade and we started with date-clj rather than struggling with Java since we were on Java 6 or Java 7 back then. We added clj-time at some point and started migrating to that, but I think that just made things more complex. Since we moved to Java 8 we started using Java Time (and clojure.java-time). We're on Java 11 right now and still have all three Clojure libraries in our code base 😐

@bfabry you have not seen what I have seen. If they’re not “competing,” I don’t even wanna know what the proper word is. I’m sure it’s absolutely filthy.

(and of course when you interact with JDBC, you tend to need java.util.Date anyway)

well there is one you're supposed to use, and 3 others that have writing on their main webpages saying "don't use this". so that's what I mean by not "competing". They're certainly all "there" and "conflicting" and "annoying" 🙂

My fav is how, no matter how much I want to use java8 dates, I’m bound to use java.util.Date by the clojure reader now.

Oh well, no going back now. c’est la vie

The reader is specifically designed not to tie types to tagged literals

Like, the whole point is tags are semantics, not types

The default type the reader uses for #inst tags is Java util date, but given a reader you control you can make it anything else

@hiredman you underestimate the dual power of ecosystem and inertia

Can you? Yes. WIll you? Maybe later 😛

and what will your deps do

Use inst-ms a lot

Reality is: I’m never gonna override #inst. I might do a custom tag, but probably not that either. Because I have #inst.

inst-ms?

clojure.core/inst-ms

WHAT THE

HOW DID I NOT KNOW THIS FN???

I FEEL BETRAYED BY ALL OF YOU

@hiredman is my only real friend

user=> (inst-ms (java.util.Date.))
1588296744460
user=> (.getTime (java.util.Date.))
1588296759500
user=>

except inst-ms works on java.time.Instants

Ah yes, just figured that out.

inst-ms ends up being a Rosetta Stone when you get a date, but are not sure what the exact type will be

Doesn’t it work on impls of the Inst protocol?

yep

Hello, please what's wrong with (use '[ring.util]) ? I want to import all functions from ring.util

It makes it harder to understand where a function is coming from. Is it clojure.core? Is it code in my current namespace? or is it used? So people tend to prefer to add an alias, so that its immediately obvious that its coming from somewhere else. There are a few exceptions, clojure.test is usually required refer’ing all (at least on JVM). And you also have the option to refer specific functions with require.

Hello, I’ve been stuck with this problem for a bit. Is the following possible? If so, could you please point me to the right direction? I’ve got a verbose function like:

(defn word2vec [{:keys [max-iter
                        step-size
                        window-size
                        max-sentence-length
                        num-partitions
                        seed
                        vector-size
                        min-count
                        input-col
                        output-col]
                 :or   {max-iter 1,
                        step-size 0.025,
                        window-size 5,
                        max-sentence-length 1000,
                        num-partitions 1,
                        seed -1961189076,
                        vector-size 100,
                        min-count 5
                        input-col "sentence"
                        output-col "features"}}]
  (-> (Word2Vec.)
      (.setMaxIter max-iter)
      (.setStepSize step-size)
      (.setWindowSize window-size)
      (.setMaxSentenceLength max-sentence-length)
      (.setNumPartitions num-partitions)
      (.setSeed seed)
      (.setVectorSize vector-size)
      (.setMinCount min-count)
      (.setInputCol input-col)
      (.setOutputCol output-col)))

(defstage word2vec
    Word2Vec
    {:input-col "sentence"
     :output-col "features"
     :max-iter 1,
     :step-size 0.025,
     :window-size 5,
     :max-sentence-length 1000,
     :num-partitions 1,
     :seed -1961189076,
     :vector-size 100,
     :min-count 5})

(defmacro set-param [spark-stage k v]
    (let [method `(symbol (str "set" (->PascalCase (name ~k))))]
      `(. ~spark-stage ~method ~v)))

  (def stage (Word2Vec.))
  (def k :max-iter)
  (set-param stage k 5) ;; throws java.lang.IllegalArgumentException

@seancorfield I rather stick to the Clojure wrapper as long as possible. I avoided Java for the recent 25 years and I'd like to keep it like that 🙂. Thank you for explaining the options though. I know that I have go out to Java anyway. When I started looking into Clojure I was a bit taken back by the attitude "it's better than Java here and better than Java there". I don't care about Java ;-).

hey everyone, trying to figure out what’s going on with my setup as follows:

(with-redefs-fn [sut/a (fn [& args] (prn "hi"))]
  (sut/b "test!"))

i think i figured it out. b'

is calling a through another thread, which perhaps is messing with the binding

with-redefs-fn isn't thread safe

yeah, if b creates a thread, with-redefs-fn needs to be forced to wait until b's thread finishes somehow (or you need something better than with-redefs-fn - eg. a dynamic binding wouldn't have this problem as they are shared with future threads and you can propagate them to other threads as needed)

i was looking at alter-var-root .. and then attempting to set it back afterwards (this is in a test)

i’d rather not change it to be dynamic just for the test

but i do like that better

@gtzogana you can use something similar to the cljs async wrapper for tests - which makes sure a form doesn't exit until a callback is called. You can make it yourself like this:

(let [done (promise)]
  (with-redefs-fn [sut/a (fn [& args]
                           (deliver done true)
                           (prn "hi"))]
    (sut/b "test!")
    @done))

if a needs to be called n times, you need a different place to deliver to done, or a conditional deliver, but the concept stays the same

oh, cool!

good idea, thanks

there's still a gotcha: with-redefs-fn / with-redefs are able to lose your original binding permanently if used in two threads at once

most test suites will never do this, but consider that this usage ensures your tests can't correctly be run concurrently

with-redefs is a strong signal that your code is missing an argument

how so?

Hey, was hoping to get some help. I'm trying to use the react-particles-js library with a reagent/re-frame project, I can get it to display, but the interactivity/hover isn't working. Was wondering if there is something glaringly obvious I'd missed, pretty new to this. This is the element in question:

[:> Particles
        {:particles {:number {:value 200
                             :density {:enable true
                                       :value_area 1000}}}
         ;; This bit doesn't work:
         :interactivity {:detect_on "canvas"
                         :events {:onhover {:enable true
                                   :mode "repluse"}}}]

I also realise that this might be the wrong thread. Should I ask in the clojurescript thread instead?

I bet #clojurescript or #reagent is more likely to have your answer

Okay thanks 🙂

What is :cljsrn I see in some cljc files on github? And how is that different from :cljs?

Hello, I have a question about Cursive and Clojure test. When I def inside a deftest the IDE says the variable cannot be resolved. How could I prevent this warning? Thanks.

hey @hammerha, I am pretty new, but I have never seen a def defined in a defn or deftest

@hammerha def is for making namespace scope definitions, if you want something to use inside ns-test use let

def there will work - sometimes - but it means every time the test runs the definition changes and all tests can see the definition, probably not what you were aiming for

(deftest ns-test (let [abc 1] (is (= ....)))

great, thanks a lot for the answer @patrick.farwick @noisesmith!

if I want to work with paths in a cross-platform manner in Clojure, what is roughly the equivalent of Node.js path module?

java.nio.file.Path

https://docs.oracle.com/en/java/javase/14/docs/api/java.base/java/nio/file/Path.html

thanks

pretty much every project I write has:

(defn path [s & ss]
  (java.nio.file.Path/of s (into-array String ss)))

fml

I'm packaging a jar using uberjar, and getting this error when I run the resulting jar file

Exception in thread "main" java.lang.NoSuchMethodError: clojure.lang.Util.loadWithClass(Ljava/lang/String;Ljava/lang/Class;)Ljava/lang/Object;
	at inspect.core.<clinit>(Unknown Source)

java -jar target/inspect.jar

How are you creating the uberjar?

using the following steps:

mkdir classes

clj -e "(compile 'inspect.core)"

clojure -A:uberjar --main-class inspect.core

java -jar target/inspect.jar

oh, you aren't using lein, deleting my message

ah yeah I should have written uberdeps not uberjar when explaining my problem

did you miss the step where you add classes to your paths?

my deps.edn looks like

{:paths ["src" "classes"]
 :deps {org.eclipse.lsp4j/org.eclipse.lsp4j {:mvn/version "0.8.1"}
        org.clojure/tools.nrepl {:mvn/version "0.2.13"}}
 :aliases {:uberjar {:deps {uberdeps {:mvn/version "0.1.10"}}
                     :main-opts ["-m" "uberdeps.uberjar"]}}}

I've seen a couple of people with this issue https://www.google.com/search?q=NoSuchMethodError%3A+clojure.lang.Util.loadWithClass but didn't find any answers

I've found depstar painless, it does what I want and even lets me use clojure.main as my entry point (pointing at my main ns) instead of having to aot compile

try delete all the files in classes

you also don't specify a clojure version in your deps

so it looks like you are compiling with one version, but what is getting packaged in the uberjar is another (older version)

yeah that looks like it's working thank you, I'll checkout depstar at some point too seems like less steps generally

I always get confused about when to add Clojure as a dependency in deps

always

ah ok my kinda rule

@sfyire If it helps in the future, if you use clj-new to create new projects, they automatically have built-in aliases to create JAR or uberjar files, and know how to deploy to Clojars etc.

https://github.com/seancorfield/clj-new -- the app and lib projects it generates use (my fork of) depstar to produce uberjars (with AOT compilation etc) and thin JARs respectively. They also have :test and :runner aliases to run your tests etc.

ah I didn't know clj-new did that, cool

@sfyire Feel free to hit me up via DM if you have any questions about clj-new or depstar -- or anything in my dot-clojure repo (which is full of "interesting" stuff to add to your ~/.clojure/deps.edn file 🙂 )