By specifying Interact's special mut_fn or immut_fn container attributes, you can add methods that would be reachable from the Interact prompt, upon reaching values that match the types on which the special methods are defined.

For example, given the following type:

#[derive(Interact)]
#[interact(mut_fn(add(param_a)))]
struct Baz(u32);

impl Baz {
    fn add(&mut self, param_a: u32) {
        self.0 += param_a;
    }
}

We can call the add methods:

>>> state.baz_val
Baz (1)

>>> state.baz_val.add(3)
>>> state.baz_val
Baz (4)