Question

I have a class:

class MyClass {
    private var num : Int;
}

I would like to know that the field has the type Int regardless of the current value which can be null for example.

Answer 1

You can’t do it at runtime without compile-time information. You can do this with either RTTI, or with macros. RTTI would be easier to implement, albeit it might be a little slower if you’d need to parse RTTI multiple times.

Your class would then become:

@:rtti
class MyClass {
    private var num : Int;
}

and to get the field type:

var rtti = haxe.rtti.Rtti.getRtti(MyClass);
for (field in rtti.fields) {
    if (field.name == "num") {
        switch (field.type) {
            case CAbstract(name, _):
                trace(name); // Int
            case _:
        }
    }
}