apeiros

module Lib
  def has_color
    define_method(:color) do 'red' end
  end
end

class Car
  extend Lib
  has_color
end

apeiros

class Object
  def chain_method(with_symbol, &new_method)
    old_method = method with_symbol
    eigenclass = class << self; self; end
    eigenclass.class_eval do
      define_method with_symbol do |*args| new_method[old_method, *args] end
    end
  end
end

apeiros

$ time ruby1.8 bits.rb 16 > /dev/null

real    0m9.861s
user    0m8.977s
sys     0m0.872s

$ time ruby1.9 bits.rb 16 > /dev/null

real    0m1.742s
user    0m1.740s

apeiros

#!/usr/bin/ruby -w

module Kernel
  ValidLocalVariableName = /\A[a-z_]\w*\z/
  
  def empty_binding
    proc{ binding }.call
  end
  
  # Dynamically define a bunch of local variables from a hash.

apeiros

h,m,s = *"23:34:02".match(/\A(\d+):(\d\d):(\d\d)\z/).captures
Time.now+h.to_i*3600+m.to_i*60+s.to_i

apeiros

module MethodCop
  # guard methods that have side effects with a callback that fires before the method is invoked. If the callback returns a "falsey" value,
  # the method is halted and will not be called. The callback will return nil instead.
  # if the method does not have side effects or you depend on its return value, you should NOT use this on that method!
  def guard_method(guarded_method, guard=nil, &callback)
    # normalize guard
    guard = method(guard) if guard.is_a?(Symbol)
    guard = callback if callback

    raise ArgumentError, "You can only supply either a guard argument or a block" if block && guard

apeiros

class Node
  attr_accessor :data, :left, :right

  def initialize(data)
    @left  = nil
    @right = nil
    @data  = data
  end

  include Comparable