`clojure.core/get` ought to support an optional 3rd arg: `not-found` (default value)

[phrohdoh]

API for clojure.core/get - Clojure v1.10.2 (stable)

(get map key)
(get map key not-found)

for src in '(get,{},:k)#_nil' '(get,{:k,:v},:k)#_:v' '(get,{},:k,:not-found)#_:not-found' '(get,{:k,:v},:k,:not-found)#_:v'; do clj -e "(prn,$src)"; done

nil
:v
:not-found
:v

ClojureRS 1a1681f supports only

(get map key)

for src in '(get,{},:k)' '(get,{:k,:v},:k)' '(get,{},:k,:not-found)' '(get,{:k,:v},:k,:not-found)'; do cargo run -- -e "$src"; done

nil
:v
#Condition["Wrong number of arguments given to function (Given: 3, Expected: 2)"]
#Condition["Wrong number of arguments given to function (Given: 3, Expected: 2)"]

[phrohdoh]

ClojureRS/src/rust_core/get.rs

Lines 15 to 27 in 1a1681f

	impl IFn for GetFn {
	fn invoke(&self, args: Vec<Rc<Value>>) -> Value {
	if args.len() != 2 {
	return Value::Condition(format!(
	"Wrong number of arguments given to function (Given: {}, Expected: 2)",
	args.len()
	));
	}
	if let Value::PersistentListMap(pmap) = &*(args.get(0).unwrap().clone()) {
	let key = args.get(1).unwrap();
	return pmap.get(key).to_value();
	}

references

ClojureRS/src/persistent_list_map.rs

Line 103 in 1a1681f

fn get(&self, key: &Rc<Value>) -> Rc<Value>;

which does not currently take an optional default Value

[phrohdoh]

A possible solution currently exists in my clojure.core/get,arity-3,not-found branch (likely to be deleted some day) which exhibits the following behavior:

for src in '(get {} :k)' '(get {:k :v} :k)' '(get {} :k :not-found)' '(get {:k :v} :k :not-found)'; do cargo run -- -e "$src"; done

nil
:v
:not-found
:v

Matching what we see from the clj usage in the original post.

That is to say, supporting (get map key) and (get map key not-found).