On 21.10.2009, at 22:28, Ken.Dickey wrote:

> Why not share the code?  Just use a "cell" to hold the class and have
> methodClass accessor do the indirection.
>
But based on which info should this indirection be made?

The idea with a simple backpointer was done because it's already there  
in case of super-sends.
So you would need to do something special there again (the last  
literal *has to be* a class
for those methds).

> If you have a bit in the method header, the VM could use it as a 0/1  
> index
> into the code to call to do (or not do) the extra indirection.

If there is something that is a scarce resource, than it's bits in the  
method header. And
I don't get it: there is one header per object, not one per reference.  
Thus
the bit could not be diffrerent per *use* of the compiledMethod.

>  Just think of
> the a trait method as a closure which is parameterized on the class.
>
> Am I missing something deep here?
>

You overlook complexity ;-)


> -KenD
>
>> Message: 7
>> Date: Wed, 21 Oct 2009 09:41:08 +0200
>> From: Adrian Lienhard <adi at netstyle.ch>
>> Subject: Re: [Pharo-project] [squeak-dev] Re: Issue with traits
>> To: The general-purpose Squeak developers list
>>         <squeak-dev at lists.squeakfoundation.org>,        Pharo  
>> Development
>>         <pharo-project at lists.gforge.inria.fr>
>> Message-ID: <3C7E5C51-21A8-483A-81A0-40854430A43B at netstyle.ch>
>> Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes
>>
>> I've fixed this issue in Pharo a couple of months ago.  
>> CompiledMethods
>> are not shared anymore, so methodClass returns the expected class. At
>> the time I implemented traits (2004?), there were no method  
>> properties
>> and hence sharing compiled methods worked -- of course except for
>> super sends in which case the method was always recompiled (so the
>> answer to Andreas' question below is b)).
>>
>> Cheers,
>> Adrian
>
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