Clojurians Log v2

Any recommendations for good reads how to build a (simple) application with Clojure? I understand the basics for data manipulation, but I struggle with control flow, user interface and working with immutability in practice.

Are there any gotchas or concerns about putting side-effects in a transduction? I searched and found https://groups.google.com/g/clojure/c/SVaFtQgtolc and my understanding is that what the original asker is doing should be fine since transduce/reduce is non-lazy. But the first line of the answer that says "Transducers are a new feature and best practices are still emerging" make me wonder if the best practice that has emerged may be that it's a bad idea for some reason.

Just inherited ` (some->> (get-in db [:hi :mom]) (into [])) Curious about (into []). Why not just a literal []? Thx!

(let [res '(:a :b :c)]
   (into [] res))
=> [:a :b :c]

(let [res '(:a :b :c)]
  [res])
=> [(:a :b :c)]

I usually use vec for this, but (into []) might communicate the intent clearer.

I have a ring-jetty server. I use 3rd party libraries in my server which make network requests (think stripe sdk). I would like to monitor the network requests my server is making. What do people like to do for this? I use Charles Proxy to monitor front end requests, but i’m not sure if this tool is also used for monitor requests my server makes :thinking_face: (apologies if there is a better channel for this post as I know it’s not really Clojure specific)

Hello, could anyone help me with the following: how do I realize a lazy seq and spit it into a edn file?

Nvm my bad I was looking into the wrong file 🙈 😂 I'm sorry

if you change a lot of code multiple times and nothing changes... maybe it is a different file xD ... hard-won lessons of coding

The nice thing of that advice is that it is independent of programming language 🙂

I am trying to find a nice linter. I currently use eastwood and kibit, what do people generally use?

I also saw https://github.com/candid82/joker

clj-kondo #clj-kondo

is there a way to use the value being threaded in cond-> in the condition used to decide whether or not to call the associated fn? if you do

(cond-> db
  true (something-that-changes-db)
  (some-cond? db) (called-conditionally)) 

will check it out. I was expecting eastwood to throw errors for unused imports

It did not.

clj-kondo will flag unused imports

https://github.com/clj-kondo/clj-kondo`

perfect

Well, db is never updated

db is a name bound to an immutable value

yeah, it makes sense that the above does not work, having looked at it, but I was wondering how I could use the updated value in that next cond

kind of like a combo between cond-> and as-> where you can thread the updated value through any position(s) you want

There is nothing built it for it, but various libraries add their own macros that do that sort thing like https://github.com/worldsingles/commons/blob/master/src/ws/clojure/extensions.clj#L50

thanks! I will take a look

The thing to watch with condp-> is that all of the conditions must be predicate expressions: you start with cond-> db true ... so that true needs to be something that db can be threaded into and will yield true.

(condp-> db (or true) (something-that-changes) (some-cond?) (called-conditionally)) might be what you need: db is threaded as the first argument into the first condition and (if truthy) the first result expression, and the result of that will be threaded into (some-cond?) and if that's truthy, it'll be threaded into (called-conditionally) -- make sense?

$ clj -Sdeps '{:deps {worldsingles/ws-commons {:mvn/version "RELEASE"}}}'
Downloading: worldsingles/ws-commons/maven-metadata.xml from clojars
Clojure 1.10.3
worldsingles/clojure/extensions.cljc on classpath.
user=> (require '[ws.clojure.extensions :refer :all])
nil
user=> (condp-> 42 (or true) (inc) (odd?) (inc))
44
user=> (condp-> 42 (or true) (inc) (even?) (inc))
43

yeah, thanks! example is super helpful

with-open with a custom closing problem looks generic enough that I am expecting something pre-written.

Maybe in a 3rd party library (not one I know about, unfortunately), but I don't think such a thing is built in.

You could use something like proxy to create a one-off object with a close method that calls your custom close method.

and use built-in with-open on that object.

I haven't done this before, so may be getting confused over whether proxy, reify, or something similar is the best choice here.