From: Patrick Ritchie <pritchie@...>
Date: 2006-02-18T23:51:28+09:00
Subject: Re: define_method fun

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Wow, that's impressive, why such huge difference?

Cheers!
Patrick

>Patrick Ritchie wrote:
>  
>
>>Hi All,
>>
>>I just setup the following in one of my classes, I'll let the code speak
>>for itself:
>>
>>["<", "<=", ">", ">=", "==", "<=>"].each do |op|
>> define_method(op) { |comparison| eval "#{self.order} #{op}
>>#{comparison.order}" }
>>end
>>
>>Ruby continues to impress me with it's ability to do so much in so few
>>amazing readable lines of code.
>>
>>Are their any good reasons not to declare my op methods this way? Is
>>their an even more efficient way to achieve the same effect?
>>    
>>
>
>It helps to pull the eval out of the define_method:
>
>
>module Order
>  attr_reader :order
>  def initialize order
>    @order = order
>  end
>end
>
>class EvalInside
>  include Order
>  ["<", "<=", ">", ">=", "==", "<=>"].each do |op|
>    define_method(op) { |comparison| eval "#{self.order} #{op}
>#{comparison.order}" }
>  end
>end
>
>class EvalOutside
>  include Order
>  ["<", "<=", ">", ">=", "==", "<=>"].each do |op|
>    eval "define_method(:#{op}) { |comparison| self.order #{op}
>comparison.order }"
>  end
>end
>
>require 'benchmark'
>
>inside = []
>outside = []
>1000000.times do |i|
>  order = rand(1)
>  inside << EvalInside.new(i)
>  outside << EvalOutside.new(i)
>end
>
>Benchmark.bmbm do |bm|
>  bm.report("eval inside") do
>    inside.sort
>  end
>
>  bm.report("eval outside") do
>    outside.sort
>  end
>end
>
>
>Rehearsal ------------------------------------------------
>eval inside   17.280000   0.030000  17.310000 ( 18.088599)
>eval outside   2.170000   0.010000   2.180000 (  2.254999)
>-------------------------------------- total: 19.490000sec
>
>                   user     system      total        real
>eval inside   17.260000   0.010000  17.270000 ( 17.873053)
>eval outside   2.150000   0.010000   2.160000 (  2.248230)
>
>
>  
>


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