Hey, I have this list called multi-select-items:

({:deleted_at nil, :value Market Research, :label A. Market Research, :id 27554, :order 0} {:deleted_at nil, :value User Interviews, :label B. User Interviews, :id 27555, :order 1})

#{27554}

Hello again! I’m trying to pass a function as a variable to a record, because I want to call it later from another namespace (the record represents some basic config variables/functions, which are needed in many places of my program). The problem is, that after destructuring the record, my function is always an unbound variable. I then experimented with records, where I can easily insert a function and call it later like this:

(defrecord hello-record [hello])

(defn hello [] (println "Hello"))

(def my-record (->hello-record hello))

(defn execute-hello [{:keys [hello]}]
  (hello))

(execute-hello my-record)
;; Hello

(defrecord hello-record [hello])

(declare hello)

(def my-record (->hello-record hello))

(defn hello [] (println "Hello"))

(defn execute-hello [{:keys [hello]}]
  (hello))

(execute-hello my-record)
;; Execution error (IllegalStateException) at user/execute-hello.
;; Attempting to call unbound fn: #'user/hello

Confusion about keywords, maps and threading opertors In a conversation with @didibus I came across his prefered way of retrieving values from a map using keywords. > Another (beginners) question that came up while studying > @didibus > ddd example was why you use the threading operator to access a map by key like (-> account :number) instead of (account :number) or even (:number account)? > Is that a matter of taste, a certain style or a hint to the compiler ? His answer was: > Just a matter of taste. If you needed to get something nested it extends to (-> account :number :value) by just adding more keys. And it works equally for Java interop: (-> javaObject .getSomething .getSomethingElse) > (-> account :number) is the same as (:number account) , the former expands into the latter, and they'll behave the same. That said, (account :number) is different, in that it will throw in the case account is nil. The others will return nil instead. I adopted that style, because I find it nice and readble. But today I stumbled across something that surprised me, when I "nested" this way of reaching into a map. Here is what I found:

(def map-a
  {::name "name"})
(def map-b
  {::key-to-use ::name})
  
(map-a ::name)
;=> "name"

(map-a (map-b ::key-to-use))
;=> "name"

(map-a (-> map-b ::key-to-use))
;=> "name"

(-> map-a ::name)
;=> "name"

(-> map-a (map-b ::key-to-use))
;=> :user/key-to-use

(-> map-a (-> map-b ::key-to-use))  
=> nil

This should be easy - but I can’t quite get it: How do I do what I mean here? (update-in {:numbers ["one" "two" "three"]} [:numbers] remove "one")

Hi! I'm pretty new to Clojure and been experimenting for a few weeks now. I might have the opportunity to build a mobile app using clojure and having trouble understanding the landscape. I'm considering React Native and Expo, but one of my concerns is that we'll just have to eject from Expo and give up the advantages we were trying to win by using it. Specifically, I want to use background GPS on iOS and android. Anyone knowledgable in this or have recommended reading?

Hiya, I’d used Clojure for over a year a few years back, but trying to get back into it… I’m on OSX, trying to get lein repl working, but its erroring:

my-project.core=> (1 2 +)
Execution error (ClassCastException) at my-project.core/eval2428 (form-init1896655737463139813.clj:1).
class java.lang.Long cannot be cast to class clojure.lang.IFn (java.lang.Long is in module java.base of loader 'bootstrap'; clojure.lang.IFn is in unnamed module of loader 'app')