Dirkjan said many things about JRuby that were patently wrong. I'd
> I'm going to pick on one thing Dirkjan said, about JRuby using hash
> tables for instance variables.
>
> Currently JRuby uses a name->index table on the object class, that
> indexes into an array on the object instance. Whilst not quite as
> efficient as compiling a class layout (or the shadow class concept
> from self), it is good enough.
>
> e.g.
>
> You have a class Foo, that has instance variables @a and @b.
> Foo.class has a table that maps @a to index 0, and @b to index 1.
> Each instance of Foo then has an array of objects of length 2, which
> stores its instance variables.
>
> To get @a of an instance of Foo, f, in pseudo-java, it would be:
>
> f.ivarTable[f.class.ivarTableIndexOf("@a")]
>
> So, each instance of Foo, need only allocate an array to hold just the
> instance variable data, instead of a generic hash table to hold both
> key+data pairs.
>
> And with jdk 7, ivar accesses are performed using method handles, so
> there is no name->index lookup on every access, the index of the ivar
> is stored in the method handle, so an ivar get/set is just an array
> element access with a constant index.
>
>
> On 12 April 2012 08:01, Tim Lossen <
[hidden email]> wrote:
>> and here it is, finally:
>>
>>
http://www.youtube.com/watch?v=AYYGage3B-I>>
>> enjoy :)
>>
>>
>> On 2012-03-12, at 20:50 , Tim Lossen wrote:
>>
>>> .... wait until you see the video! :)
>>>
>>> On 2012-03-12, at 6:29 PM, Thomas E Enebo wrote:
>>>
>>>> OMG! :)
>>>>
>>>> -Tom
>>>>
>>>> On Sat, Mar 10, 2012 at 4:00 PM, Tim Lossen <
[hidden email]> wrote:
>>>>> here are my slides -- it was an epic battle:
>>>>>
>>>>>
http://www.slideshare.net/tim.lossen.de/jruby-vs-rubinius>>>>>
>>>>> PWNED!
>>>>>
>>>>>
>>>>> --
>>>>>
http://tim.lossen.de>>>>>
>>>>>
>>>>>
>>>>>
>>>>> ---------------------------------------------------------------------
>>>>> To unsubscribe from this list, please visit:
>>>>>
>>>>>
http://xircles.codehaus.org/manage_email>>>>>
>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> blog:
http://blog.enebo.com twitter: tom_enebo
>>>> mail:
[hidden email]
>>>>
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>>>> To unsubscribe from this list, please visit:
>>>>
>>>>
http://xircles.codehaus.org/manage_email>>>>
>>>>
>>>
>>> --
>>>
http://tim.lossen.de>>>
>>>
>>> ---------------------------------------------------------------------
>>> To unsubscribe from this list, please visit:
>>>
>>>
http://xircles.codehaus.org/manage_email>>>
>>>
>>
>> --
>>
http://tim.lossen.de>>
>>
>>
>>
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>>
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>>
>
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>
Locked
