From: Christoph <chr_mail@...>
Date: 2005-05-18T05:20:12+09:00
Subject: Re: Extending an Instance only Once

peter.vanbroekhoven@gmail.com schrieb:

>You made a typo in your tests (x should be replaced with f), but it
>does not influence the result. The only explanation I have is that the
>test used in include is more complicated than the one used in #is_a?
>because include doesn't only check the module passed as parameter to
>#include, it checks modules included in that module too. I guess even
>when there are no such modules, there is still some overhead (it's not
>exactly a straightforward algorithm). But unless you really intend to
>do 500000 extends in a row, I don't think that is really a problem...
>:-)
>  
>
The explanation is probably simpler -  f.extend(M) makes hook calls to
M.extend_object(f)  and M.extended(f) - M.extend_object(f)  probably
tests if  f.is_a?(M) a - this means its 4 method calls, versus 1 call + 
1 if statement  ...
you'll probably find a much smaller difference calling 
M.extend_object(f)  only.


---
require 'benchmark'
include Benchmark

module M
class Bar < Array; end
class Foo < Bar; end

n = 500000
bm(15){ |x|
     f = Foo.new
    x.report( "Test First" ){
        n.times{
            extend_object( f ) unless f.is_a?( M )
        }
    }
    f = Foo.new
    x.report( "Always Extend" ){
        n.times{
          extend_object( f )
        }
    }
}
end
---

/Christoph

>Peter
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