From: Boris Prinz <boris.prinz@...>
Date: 2006-07-18T02:47:03+09:00
Subject: [QUIZ][SOLUTION] Negative Sleep (#87)

Hi,

I tried to keep it simple. The code blocks in an Insomnia object are
assumed to be executed infinitely fast. Sleeping a negative amount means
that the following block is run before the preceding block.

Code blocks are stored in a hash where the key is the relative time  
(@t) and the
value is an array of Proc objects. The run method simply sorts by  
time and calls
the procs after sleeping (Kernel) the required number of seconds.

Cheers,
Boris



class Insomnia
   # It's really sick to call this method 'do',
   # but I can't think of a better name...
   def do(&block)
     @blocks[@t] << block
   end

   def sleep(seconds)
     @t += seconds
   end

   def run
     times = @blocks.keys.sort
     t_now = times.min
     times.each do |t|
       Kernel.sleep(t - t_now)
       t_now = t
       @blocks[t].each {|b| b.call}
     end
   end

   def initialize
     @blocks = Hash.new {|h, t| h[t] = []}
     @t = 0
     yield(self)
     run
   end
end

Insomnia.new do |i|
   i.do { puts "Something will explode in ten seconds:" }
   i.sleep(10)
   i.do { puts "Boom!" }

   # countdown:
   1.upto(9) do |num|
     i.sleep(-1)
     i.do { puts num.to_s }
   end
end