Clojure Syntax

3 min read, 506 words clojuresyntax

What is :: notation in clojure?

Shorthand to use current namespace. :app.client/person --> ::person Localized name

How to define/declare global variables with in namespaces?

def block is like Assignment operator = in other languages

What is the difference b/w let and def?

The syntax for them is different, even if the meanings are related.

let takes a list of bindings (name value pairs) followed by expressions to evaluate in the context of those binding. let binds symbols to values in a "lexical scope"

def just takes one binding, not a list, and adds it to the global context.

How to use docs on REPL?

(require '[clojure.repl :refer :all])

doc, find-doc, apropos, source, and dir

What is underscore in reframe?

The underscore is the universal ignore symbol. Its a valid symbol indentifier

(let [_ 1] (println _))

How to add dependency? to manipulate DOM via google closure library?

What is the difference between :refer and :as in cljs declerations?

How to namespce in clojure? (opens new window)

keyword	description
:as	as an namespace Alias
:refer	makes it look like a local function

What are these clojure keywords?

macros	what does it do?
:require	loads a library, function, external code
:namespaces	mappings from symbols to vars, are first-class and dynamic. Can query ns all-ns. aka Modules
SYmbols (opens new window)	Symbols in Clojure are just pieces of data, Clojure uses them as identifiers for various values and references. aka Identifiers
(defn ^:export init [] (...))	kick off app when HTML is loaded, same as window.load(callback)

How to view/list app-db in js console?

app-name.db in js console. Eg: conduit.db

How to convert js arrays and objects to clojurescript data structures?

https://cljs.github.io/api/cljs.core/js-GTclj (opens new window)

what is .- in js interop?

.- is used to signify field access in Clojure interop, just . is calling a method.

How to reference and use js this in cljs?

https://clojureverse.org/t/reagent-adding-event-listener-to-a-component/5896 (opens new window) cljs api (opens new window)

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