The orrible first implementation of the trace class problem

trace_class_reloaded.rb

module TraceCalls

  def self.included(including_class)
    def including_class.method_added(name)
      return if @_adding_a_method
      @_adding_a_method = true
      TraceCalls.wrap_method(self, name)
      @_adding_a_method = false
    end
  end

  def self.wrap_method(klass, name)
    original_method = "original_#{name}"
    body = %{
      alias_method :#{original_method}, :#{name}
      def #{name}(*args, &block)
        puts "==> Calling #{name} with \#{args.inspect}"
        result = #{original_method}(*args, &block)
        puts "<== result = \#{result}"
        result
      end
    }
    klass.class_eval body
  end

end

class Example
  include TraceCalls

  def some_method(arg1, arg2)
    arg1 + arg2
  end

  def method2(arg)
    yield * arg
  end
  def name=(val)
    @name = val
  end

  def name
    @name
  end

end

ex = Example.new
ex.some_method(4,5)
ex.method2(99) {2}
ex.name = "Piero"
puts ex.name