gistfile1.rb

module Trigo
  [:sin, :cos, :tan].each do |trigo_fun|
    class_eval <<-RUBY_EVAL, __FILE__, __LINE__
      def #{trigo_fun}(angle)
        _trigo(:#{trigo_fun}, angle)
      end
    RUBY_EVAL
  end
  
  private
  def _trigo(fun_name, angle)
    assert_type angle, :Number
    Number.new(Math.send(fun_name, _to_radius(angle.value)), angle.numerator_units)
  end
  
  FULL_CIRCLE = 360.0
  def _to_radius(value)
    Math::PI * (value / FULL_CIRCLE)
  end
end