ref: 02ac617541ca1a7bf82b1615fb5a58235469b5d3
dir: /appl/demo/lego/timers.m/
Timers : module{ Timer : adt { id : int; tick : chan of int; reset : fn (t : self ref Timer); cancel : fn (t : self ref Timer); destroy : fn (t : self ref Timer); }; init : fn (res : int); new : fn(ms, rep : int) : ref Timer; };