Attribute Macro Methods 

#[Methods]

Gives interactive access to a structs methods.

Only methods with supported argument types will be made interactive.

Currently supported argument types are:

bool, char, f32, f64, i8, i16, i32, i64, i128, isize, u8, u16, u32, u64, u128, usize, String, str

References to these types are also supported.

Generic argument types are not supported.

Both String and str are only available with default features on.

What it does:

#[Methods]
impl Struct {
    fn ping(&self) -> &str {
        "pong"
    }
    fn frob(&mut self, arg: u32){
        unimplemented!()
    }
}

Expands to something like: (notice how frob is only available inside eval_method_mut)

impl Methods for Struct {
    fn eval_method(&self, method_name: &str, args: &str, f: &mut dyn FnMut(Result<'_, &dyn Debug>)) {
        match method_name {
            "ping" => match parse_0_args(method_name, args) {
                Ok(()) => f(Ok(&self.ping())),
                Err(e) => f(Err(e)),
            },
            _ => f(Err(MethodNotFound {
                type_name: "Struct",
                method_name,
            })),
        }
    }
    fn eval_method_mut(&mut self, method_name: &str, args: &str, f: &mut dyn FnMut(Result<'_, &dyn Debug>)) {
        match method_name {
            "ping" => match parse_0_args(method_name, args) {
                Ok(()) => f(Ok(&self.ping())),
                Err(e) => f(Err(e)),
            },
            "frob" => match parse_1_arg(method_name, args) {
                Ok((arg0,)) => f(Ok(&self.frob(arg0))),
                Err(e) => f(Err(e)),
            },
            _ => f(Err(MethodNotFound {
                type_name: "Struct",
                method_name,
            })),
        }
    }
    fn get_all_method_names(&self) -> &'static [&'static str] {
        &["ping", "frob"]
    }
}