Is it possible to use ref parameters in functions?

[philpax]

Hi there,

I am in the process of binding jint to my application, and am enjoying the experience. I've used the CLR interop to expose ImGUI.NET, which has methods with signatures like this:
public static bool Checkbox(string label, ref bool v)

A cursory attempt to use this the naive way (ImGui.Checkbox("Some Label", bool_variable)) results in an overload resolution error:
No public methods with the specified arguments were found.

My guess is that there's no way to make this work 'out of the box', given that JS doesn't have explicit-ref semantics. I'm seeking confirmation on that before I start writing wrappers to hide the refs from the API 😅

[lahma]

Currently this is not possible, like you've discovered. It can become quite hard to support as under the hood the JsBoolean parameter is converted to bool. This would mean that Jint would need to track ref-passed parameters and then set the value back to given variable name the way it's after the function call. Probably not impossible, but can get quite hairy...

[philpax]

Yup, that makes sense - there's also not really much precedent for this on the JS side (it would be weird to see let val = true; sets_to_false(val); assert(val == false)). If this was something that the project wanted to implement in future, it'd best be done with some kind of wrapper IMO, like:

let val = jintRef(true);
sets_to_false(val);
assert(val == false);

That being said, appreciate the answer! I'll just have to expose a more JS-idiomatic interface for the functions I care about 😅