Data Noise

How often did you write this kind of code?

    def initialize(arg1, arg2, arg3)
      @arg1 = arg1
      @arg2 = arg2
      @arg3 = arg3
    end

All this constructor does it propagates parameters to initialize method to instance variables. In Ruby, there is a better way:

    class Binding
      def local_to_instance
        eval("local_variables").each do |name|
          eval("self").instance_variable_set("@#{name}", eval(name))
        end
      end

      alias :kernel_eval :eval
      def eval(code)
        kernel_eval(code, self)
      end
    end

    class Test
      attr_accessor :arg1, :arg2, :arg3

      def initialize(arg1, arg2, arg3)
        binding.local_to_instance
      end
    end

    t = Test.new(1,2,3)
    puts t.arg1
    # => 1
    puts t.arg3
    # => 3
    p t
    # => #<Test:0x1c6600 @arg1=1, @arg3=3, @arg2=2>

Note that Ruby 1.9 already provides Binding#eval method, so you don't need this kernel_eval hack.

I know this kind of silly and, I guess, inefficient. But still.