From: Paolo Negri <hungrylist@...>
Date: 2006-10-30T03:56:02+09:00
Subject: Re: [QUIZ] Fuzzy Time (#99)

Hi all

Here's is my script. It was fun working at it, just please no more
time based quiz when there's the switching of daylight time saving :P
The scripts defines two class one to manage how to move within a given
range and one for actual FuzzyTime implementation.
At the end of the email there's a really ugly extra file you may want
to use to play with the FuzzyTime class.

Paolo

#!/bin/ruby
class WanderingWalker
  SIGN = [1, -1]
  CHECK_LIMIT = %w(min max)
  DEFAULT_GENERATOR = lambda { |limit| rand(limit) * SIGN[rand(2)] }
  attr_reader :position, :limit, :target
  alias :level :position
  def initialize(limit, &block)
    @limit = limit
    @generator = block_given? ? block : DEFAULT_GENERATOR
    @position = 0
    generate_target
  end
  def walk(steps)
    generate_target while @position == @target
    new_pos = [(@position + direction*steps), @target].send  \
      CHECK_LIMIT[SIGN.index(direction)]
    @position = new_pos
  end
  def distance
    @target - @position
  end
  def direction
    if distance == 0 : 1 else distance/distance.abs end
  end
  private
  def generate_target
    @target = @generator.call limit
  end
end

class FuzzyTime
  FORMATS = %w(%H:%M %I:%M)
  attr_reader :fuzziness
  #two params, both optional time and an hash
  #time: a time object used as the starting point
  #hash params
  #:hidden_digits - hidden_digits number, from right
  #:precision - maximum distance from real time in seconds
  def initialize(time=Time.new, opts={})
    @internaltime = time
    @last_call = @printed_time  = Time.new
    @precision = opts[:precision] || 300
    @fuzziness = WanderingWalker.new(@precision)
    @format = FORMATS[0]
    @hidden_digits = opts[:hidden_digits] || 1
    @sub_args = case @hidden_digits
      when 0 : [//, '']
      when 1 : [/\d$/, '~']
      when 2 : [/\d{2}$/, '~~']
      when 3 : [/\d:\d{2}$/, '~:~~']
      else
        raise "nothing to see!"
    end
  end
  def advance(secs)
    tic(secs)
  end
  def update
    tic Time.new - @last_call
  end
  def actual
    @internaltime
  end
  #switch 12 / 24h format
  def toggle_format
    @format = FORMATS[FORMATS.index(@format) == 0 ? 1 : 0]
  end
  def to_s
    @printed_time = [@printed_time, (@internaltime + fuzziness.level)].max
    @printed_time.strftime(@format).sub(*@sub_args)
  end
  private
  def tic(secs=1)
    @internaltime += secs
    @last_call = Time.new
    @fuzziness.walk secs
  end
end

Ad here's the super ugly runner script

#!/bin/ruby
require 'fuzzy_time'
# accepts a FuzzyTime object as argument + an hash of options
#possible options
# :time_warp if true instead of working as a clock just prints out
#in an instant all the clock output, if false, works as a clock
# :step_size how often the clock will be updated in seconds
# :print_actual prints the actual time
# :print_fuzziness, prints the error size
# :toggle switch at every step from 24 to 12 hour format
# :duration how many step_size the clock should run
class FuzzyExec
  def initialize(ft = FuzzyTime.new ,opts = {})
    opt_def = {:duration => 100, :step_size => 60, :print_actual => true}
    @opts = opt_def.update opts
    @ft = ft
  end
  def show_fuzzy_clock
    @opts[:duration].times do
      @ft.toggle_format if @opts[:toggle]
      out = []
      out << @ft.to_s
      out << @ft.actual.strftime('%H:%M') if @opts[:print_actual]
      out << @ft.fuzziness.level if @opts[:print_fuzziness]
      out << Time.new.strftime('%H:%M') if @opts[:print_current]
      puts out.join ' '
      if @opts[:time_warp]
        @ft.advance(@opts[:step_size])
      else
        sleep @opts[:step_size]
        @ft.update
      end
    end
  end
end