Watchvars: module {	PATH: con "/dis/lib/watchvars.dis";	Watchvar: adt[T] {		c: chan of (T, chan of T); 		new:	fn(v: T): Watchvar[T];		get:	fn(e: self Watchvar[T]): T;		set:	fn(e: self Watchvar[T], v: T);		wait:	fn(e: self Watchvar[T]): T;		waitc:	fn(e: self Watchvar[T]): (T, chan of T);		waited:	fn(e: self Watchvar[T], ic: chan of T, v: T);	};};