Fun with runtime method names

Executing arbitrary method names makes code so much simpler. You don't have to branch or use lookup tables or any of that. Here's the heart of a simple calculator:

class Calculator
  def initialize()
    [...]
    button_1.action = Action.new( self, :number_pressed, [1] )
    button_2.action = Action.new( self, :number_pressed, [2] )
    button_add.action = Action.new( self, :operator_pressed, [:+] )
  end

  def number_pressed( number )
    @input += number.to_s
    puts @input
  end

  def operator_pressed( operator )
    @value = @value.send( @last_op, @input.to_f )
    @input = ''
    @last_op = operator
    puts @value
  end
end