spawn_listener2

[jesse99]

Seeing how there is a comm::select2 I think that it would be useful to have a spawn_listener2. Fwiw the use case I have in mind is a task that allows other tasks to get copies of and mutate state shared by the tasks:

fn manage_state(get_state_port: comm::port<comm::chan<str>>, set_state_port: comm::port<str>)
{
    let mut state = "default";

    loop
    {
        alt comm::select2(get_state_port, set_state_port)
        {
            either::left(channel)
            {
                comm::send(channel, copy(state));
            }
            either::right(new_state)
            {
                state = new_state;
            }
        }
    }
}

[nikomatsakis]

why would you use two ports in place of a port with an enum message like:

enum msg { get(channel), set(value) }

?

[jesse99]

I was trying to leverage the type system so that reader tasks could only read state and writer tasks could only write state. It's probably not that big of a deal though and the code is simpler with an enum like the above.

[catamorphism]

Closing since it sounds like there's a good workaround for this.