I can't access the code standards for libraries in Clojure. There's any other link about that?

what do you mean code standards @iagwanderson

something like the clojure style guide but for building libraries

there is a link inside the clojure style guide for that documentation but it's not working right now

503: This site is currently undergoing maintenance. We apologize for the inconvenience.

What link?

If it’s the contrib style docs, that’s moved

https://clojure.org/community/contrib_howto - under Coding Guidelines

its

(that's the broken link i mean)

pr'ed

I edited the page with their web UI and now there's a "proposed file change" somewhere ¯\(ツ)/¯

my pr is at https://github.com/bbatsov/clojure-style-guide/pull/174

yeah i did my ui change and came back to see you had done it as well 🙂 except you used the anchor tag as well

so its better

i just don't know how to rescind mine lol

thanks for the directions

I find myself traveling without internet access - are there any downloadable documentation resources? I’m thinking api doc, cheat sheet, etc. I’m learning 😅

Greetings, folks!

Just curious about what’s the usual libs you use for mocking if any. I’m asking in the context of testing side-effects of code in an isolated manner (writing to DB or making http reqs). I found https://github.com/bguthrie/shrubbery which seems what I was looking for (not sure if it’s in active dev). Any other recommendations? Thanks!

is there an easy way to interrogate a dependency library for its namespaces, from the REPL? I just realised I've been going and looking it up the long way

I'm using lein if that matters

^ Unfortunately no. There is no reliable way to get namespaces from artefacts. Rich even joked about it in Spec-ulation, "Somebody on the street tells you, did you try this jar? I has fred in it" There may be some programmatically accessible API somewhere that gives you this information but ultimately a human has to put it in.

that's a shame but thanks for your help

So I'm trying to access a var in the namespace backend.core from a different namespace backend.routes.config but for some reason I get the error java.lang.RuntimeException: No such var: backend.core/config

presumably backend.core starts with a (ns backend.core ...) form. Are you requiring [backend.core :as backend.core] in backend.routes.config?

I think it’s confusing to have aliases with .’s in them

it looks like a fully qualified var at that point?

I guess there is no way to add environment variables to aliases in deps.edn as you can do in Leiningen since I didn't find anything like that in the deps.edn documentation? Can you recommend some Clojure library that reads configuration from some file (edn, properties...) and I can ask certain property and the library first checks if the environment variable exists, and if yes returns the value, if not then tries to read the property from the file.

Check out https://github.com/metosin/maailma

https://github.com/weavejester/environ is a popular alternative

Environ README says nothing about reading config from file and merging it with environment variables.

How about aero? https://github.com/juxt/aero

Yep, sorry I remembered wrong that environ could read EDN config files as well. My bad.

iirc, luminus uses cprop for this:

(ns my-project.config
  (:require [cprop.core :refer [load-config]]
            [cprop.source :as source]
            [mount.core :refer [args defstate]]))

(defstate env
  :start
  (load-config
    :merge
    [(args)
     (source/from-system-props)
     (source/from-env)]))

Thanks. Maybe I check cprop as well.

Stupid question. Using CLJS i'm trying to send a file to my server using transit. I'm getting the following error:

Uncaught Error: Cannot write File
Cannot write File
    at Object.writer.marshal (writer.js:447)
    at Object.writer.emitMap (writer.js:319)
    at Object.writer.marshal (writer.js:439)
    at Object.writer.marshalTop (writer.js:471)
    at Transit$Writer.writer.Writer.write (writer.js:501)
    at cognitect$transit$write (transit.cljs?rel=1557151648550:278)
    at ajax$transit$transit_write_fn_$_transit_write_params (transit.cljc?rel=1557151648575:17)
    at ajax$interceptors$apply_request_format (interceptors.cljc?rel=1557151648359:150)
    at Object.ajax$protocols$Interceptor$_process_request$arity$2 (interceptors.cljc?rel=1557151648359:161)
    at ajax$protocols$_process_request (protocols.cljc?rel=1557151648127:32)

transit doesn't know how to encode the File object you are passing it

https://github.com/cognitect/transit-cljs#default-type-mapping are the types transit-cljs knows how to encode out of the box

@hiredman: thank you. I did actually see that, essentially I'd need to figure out my own way of encoding/decoding this?

yes

I would start by not trying to serialize a File

a file is sort of a pair of some data and some name for that data on some filesystem

the place when you send the data likely doesn't have the filesystem context there, so sending a file is kind of meh

so instead send a pair of a name and some data (maybe some kind of array, I don't really do much js or cljs so I don't know what the best type for a collection of binary data is)

http://blog.cognitect.com/blog/2015/9/10/extending-transit might be useful to you

Oh man, I had expected that this would be a pretty typical usecase. I'm surprised at how much is about to be involved

Thanks @hiredman and @alexmiller

https://github.com/nginx-clojure/nginx-clojure has a websocket allowing text or binary, was real easy to set up, and get images from the front-end to the back end.

I used mount (https://github.com/tolitius/mount) and cprop (https://github.com/tolitius/cprop) to implement the application state and configuration handling in my new Clojure study project. I was amazed how incredibly easy and clean the implementation was. I can strongly recommend both libraries for beginners. I only now realized that both libraries are made by the same person. Thanks @tolitius!

just realized that mount and cprop have the same author. I use them, too. thanks 🙂

Hi, I have what should be a fairly simple macro question (man I really struggle to actually understand how to construct macros…). I have the following code:

(defmacro defx
  [id form]
  `(defmethod x ~id [_]
     (quote ~form)))

(defx "foo" (s/keys :req-un [::a ::b]))
;; Call to clojure.core/fn did not conform to spec (reason: "Extra input")

i think you might need _# for the arg in your macro

I believe that something like that is true for any parameters inside of a syntax-quoted expression -- if you do not do something like name# it will be qualified with the name of the current namespace, e.g. , and I don't think Clojure supports that for a parameter name.

name# is shorthand for gensym, and is almost always what you want (so you don’t shadow or redef any existing vars). however you can explicitly specify a symbol if you really want to (e.g. ~'_)

Yep, that did the trick! Thanks 🙂

can't you do '_ as well?

that gives you (defmethod x id [(quote _)] ...) which is an error

nested quotes are not idempotent, thus the quote/unquote combo

Generally you can always use macroexpand to see the expanded form, that usually gives a better clue of what the error is

user=> (macroexpand '(defx "foo" (s/keys :req-un [::a ::b])))

(. user/x clojure.core/addMethod "foo" (clojure.core/fn [user/_] (quote (s/keys :req-un [:user/a :user/b]))))

(defmacro defx
  [id form]
  `(defmethod x ~id [~'_]
     (quote ~form)))

Oh, hah... @matt.kipps already edited his answer to mention that.

What I saw in Zulip:

**matt.kipps:** not necessarily. `name#` is shorthand for gensym, and is almost always what you want (so you don’t shadow or redef any existing vars). however you can explicitly specify a symbol if you really want to…