benchmark.rb

require 'benchmark'
require 'logger'

class Module
  def alias_method_chain( target, feature )
    alias_method "#{target}_without_#{feature}", target
    alias_method target, "#{target}_with_#{feature}"
  end
end unless Module.public_method_defined?(:alias_method_chain)

module Gasper
  module Benchmark
    class << self
      def included(klass)
        klass.extend ClassMethods
      end
    end

    module ClassMethods

      def benchmarked_dump(msg)
        $stderr.puts(msg)
      end

      def benchmarked_method(*methods)
        methods.each do |method|
          class_eval %Q(
            define_method("#{method.to_s}_with_benchmark".to_sym) do |*args, &block|
              result = nil
              runtime = ::Benchmark.realtime do
                result = send(__method__.to_s.sub(/_with_/, '_without_').to_sym, *args, &block)
              end
              benchmarked_dump('benchmark for ' + __method__.to_s.sub(/_with_.*$/, '') + ': ' + runtime.to_s)
              return result
            end
          )
          alias_method_chain method, :benchmark
        end
      end
    end
  end
end


=begin

  = Usage =

  class String
    include Gasper::Benchmark

    benchmarked_method :scan, :upcase
    benchmarked_method :gsub
  end

  "test".scan(/e/).first
  scan: 4.291534423828125e-05
  => "e"

  "test".upcase
  scan: 3.14155342135614e-05
  => "TEST"

  "test".gsub(/t/,'X')
  gsub: 3.337860107421875e-05
  => "XesX"

=end