ref: 4e1b511d026220c7f5dbe4f62d114bef418cdcf9
dir: /module/lock.m/
Lock: module { PATH: con "/dis/lib/lock.dis"; Semaphore: adt { c: chan of int; obtain: fn(nil: self ref Semaphore); release: fn(nil: self ref Semaphore); new: fn(): ref Semaphore; }; init: fn(); };