Ruby Runtime Feature Changes

main.rb

p = Person.new
p.refresh # => (...)

Person.start_trace
p.refresh # => (...)
# -> refresh: 0.500 s.

Person.end_trace
p.refresh # => (...)

monkey_patching.rb

class Person
  TIMED_METHODS = [:refresh, :dup]
  TIMED_METHODS.each do |method|
    # set up _without_timing alias of original method
    alias_method :"#{method}_without_timing", method

    # set up _with_timing method that wraps the original in timing code
    define_method :"#{method}_with_timing" do
      start_time = Time.now.to_f
      
      returning(self.send(:"#{method}_without_timing")) do
        end_time = Time.now.to_f

        puts "#{method}: #{"%.3f" % (end_time-start_time)} s."
      end
    end
  end
end

person.rb

class Person
  def refresh
    puts "I am refreshing"
  end

  def dup 
    puts "Duplicated"
  end
end

ruby_runtime_feature_changes.rb

class << Person
  TIMED_METHODS = [:refresh, :dup]

  def start_trace
    TIMED_METHODS.each do |method|
      alias_method method, :"#{method}_with_timing"
    end
  end

  def end_trace
    TIMED_METHODS.each do |method|
      alias_method method, :"#{method}_without_timing"
    end
  end
end