module type WATCHER_FUN = sig .. end
sig
end
WATCHER_FUN is like Tick.WATCHER but defines Tick.WATCHER_FUN.triggers as functions in which you get the the watcher.
WATCHER_FUN
Tick.WATCHER
Tick.WATCHER_FUN.trigger
type t
type trigger = t -> unit
t -> unit
include Tick.WATCHER