So in javascript we can access the member of any object by just using []. For example:

let obj = { foo : 'bar'};
let accessedField = obj["foo"];
obj["foo"] = "something"

How can I access a member of a namespace without knowing the name of the member beforehand like if I get it from somewhere else as input, a string/char* for example. Not necessarily looking for the operator[] implementation.

namespace Foo {
   int bar = 2;
}

Foo["bar"] = 3;

The reason is so I can dynamically access items and I don't want too use std::maps.

**EDIT: Just to clarify not necessarily the [] operator but any way to dynamically access a member of a namespace without knowing it beforehand.