What's wrong with this:

a := Actor(ActorPool()) | Channel channel | {
   channel.join(bot)
}

i get this:

Receive func not immutable: |fancore::Channel->sys::Obj|
sys::NotImmutableErr: Receive func not immutable: |fancore::Channel->sys::Obj|

Is bot final or const? See http://fandev.org/doc/docLang/Functions.html#immutable

it's actually a reference to this that I thought was necessary because I'm used to anonymous inner classes. But then I remembered that closures aren't AIN so I changed it to use this but I still have the problem. I'm thinking that passing in this is the problem but I'm not sure how I'd get around it without redoing the API I'm building on.

If this is const then closures which capture it will be immutable:

const class Foo
{
  Void main()
  {
    f := |,| { echo(this) }
    echo(f.isImmutable)
  }
}

This will print true. However if Foo is not-const, then the f will always be mutable.

If you can explain a bit more about what you are doing, perhaps I can offer some other suggestions.

Perhaps we can hook up on irc later in the week and we can walk through this. I'm gonna get on a plane in the morning so I won't be around much for the next day+ or so...