Clojurians Log v2

We used to have it integrated but never used it. If you have specific questions I can look in our archives if you'd like. Just let me know

REPL driven development question… When I want to test a line in a function that depends on an argument without calling the function, what do you do to provide a value for the argument? Do you just throw in a ‘def’ or is there a better way?

I would do a let - doesn’t def create global scope?

What I often do is pull the line out of the function, and execute it in the repl, wrapped in a let

Doesn’t always work of course

@dcreno Put a (comment ,,,) form immediately after the function. Then put (def addend 4) inside that comment and evaluate the def, then you can eval any form inside the function.

That way you're not modifying the "production code", but your scratch code stays visible and available in your code for future use.

And maybe attend one of my online talks in December/January https://corfield.org/blog/2020/11/24/talks-clojures-superpower/ 🙂

Thanks! I know it’s a bit of a silly question but I figured there was a common way.

I like the (comment …) version.

"Rich Comment Form"

(because Rich Hickey does this too)

(and definitely not a "silly question" -- getting to a really efficient RDD workflow is something that a lot of people struggle with, because it's not like how you work with other languages)

How can fix the error:

clojure -M:uberjar
Compiling yubrshen.unique-errors ...

Compilation of yubrshen.unique-errors failed!

Could not locate yubrshen/unique_errors__init.class, yubrshen/unique_errors.clj or yubrshen/unique_errors.cljc on classpath. Please check that namespaces with dashes use underscores in the Clojure file name.

:uberjar {:extra-deps {seancorfield/depstar {:mvn/version "1.1.128"}}
            :main-opts ["-m" "hf.depstar.uberjar" "unique_errors.jar"
                        "-C" "-m" "yubrshen.unique-errors"]}

What are the file/folder names used? It looks like a classpath error. Your namespace yubrshen.unique-errors includes a dash which is okay, but your filenames should uses underscores, replacing the dashes.

Hello everyone, is there a way to get the query result without the brackets?

(d/q '[:find (pull ?e [:commit/rev])
         :in $ $date
         :where
         [?e :commit/date ?date]
         [(> ?date $date)]]
       @conn date)

;; => ([#:commit{:rev "25ed6cb"}]
;;     [#:commit{:rev "02a760a"}]
;;     [#:commit{:rev "61df934"}]
;;     [#:commit{:rev "d6524ab"}])

(->> result
       (reduce (fn [acc e] (conj acc (first e))) '()))

;; => (#:commit{:rev "4e2cce7"}
       #:commit{:rev "13c57d1"}
       #:commit{:rev "8a3fd52"})

@lukas.block you can try doing this if it helps:

(map first result)
;; or
(->> result
     (map first))

I believe there’s a way to do it in the query without extra work afterwards

hey thank you. The reduce was just an, I have to admit overly complicated example, for an extra step

What is a good tool to ‘make 150 http requests (random order) with N workers’ ? Should I reach out to java.util.concurrent?

Going to do now with what I am familiar with .. java.util.concurrent.ExecutorService but I am interested in learning more about clojure.async which also seems to be able to do this

Client libraries like httpkit allow you to pass an optional thread pool (number of workers). You can then use core.async's async-pipeline to control the number of inflight requests

I need to investigate that. Right now I have a simpler approach:

(defn ping-endpoints [endpoints]
  (let [pool (Executors/newFixedThreadPool 8)
        tasks (for [url endpoints] #(ping-endpoint url))
        futures (.invokeAll pool tasks)]
    (for [f futures] (.get f))))

I wish I could just keep all data in memory and not bother with databases

Apparently the 4clojure server is down hmmm

Anyway, am doing qn 39 have a solution to make my own version of interleave but is there a way I can remove vector ? Like by changing concat to something else?

(defn leave [a b]
  (when (and (not-empty a) (not-empty b))
    (concat (vector (first a)) (vector (first b))
            (leave (rest a) (rest b)))))

You don't care if your data disappears when the power goes off?

I believe quite a few databases are good at keeping recently used data cached in RAM.

I think you can use list* there

yeap list works too but was wondering if there's a concat that doesn't require elements to be in some form of collection

List* is that

Distinct from list. Often you’ll see lazy-seq cons cons leave

oooo! yeap it works

Also does anyone understand why mapcat vector works as a replacement for interleave ?

Okay nvm I got it, but I never knew that map applies the f to the first item of each coll then the second items and so on

yeah its a neat feature of map. other languages need a bespke map2, map3, etc