From: Daniel Moore <yahivin@...>
Date: 2009-03-08T04:52:47+09:00
Subject: [SUMMARY] Polyrhythm Trainer (#194)

This quiz may be worthy of a revisit in the future. Until then, here
is my solution: the beginnings of an "Annoyance" trainer.

    # rhythm.rb

    class Rhythm
      BPM = 20
      SECONDS_PER_MINUTE = 60.0

      def initialize(n, sym)
        @sym = sym
        @seconds_per_hit = SECONDS_PER_MINUTE/(BPM*n)
        @last_hit = @seconds_per_hit
        @hit_count = 0
        @time = 0

        puts @seconds_per_hit
      end

      def elapse(time_elapsed)
        hit = false
        if @last_hit >= @seconds_per_hit
          @hit_count += 1
          @last_hit -= @seconds_per_hit
          puts "#{"%1.3f" % @time}: #{@sym}"
          hit = true
        end
        @time += time_elapsed
        @last_hit += time_elapsed
        return hit
      end
    end

    s = '@'

    rhythms = ARGV.map{|arg| Rhythm.new(arg.to_i, s = s.succ)}

    delta = 0.05
    time = 0

    while true
      hit = rhythms.map{|r| r.elapse(delta)}.inject(false) {|hit, r| hit || r}
      print "\a" if hit
      time += delta
      sleep delta
    end

The program will beep indefinitely, producing a sound every time the
rhythm should be struck (to the nearest 20th of a second).

    Usage: ruby rhythm.rb [rhythms]

    EX: > ruby rhythm.rb 3 2
    1.0
    1.5
    0.000: A
    0.000: B
    1.000: A
    1.500: B
    2.000: A
    3.000: A
    3.000: B
    4.000: A
    4.500: B
    5.000: A

Crank up the volume on your PC speaker and have a blast near your co-workers!

http://rubyquiz.strd6.com/quizzes/194