Re: The standard does *not* support - a removeAll: a - [was: Re: [BUG]

Jesse Welton wrote:
> Stephan Rudlof wrote:
> 
>>[...]
>>Since we have an 'uncaptured' parameter, the receiver *has* *to* never
>>retain a reference to the parameter, directly or indirectly, as a result of
>>this message.
>>
>>Further: The parameter *is* the receiver in the case of
>>    a removeAll: a
>>. Has this receiver a direct reference to itself? I don't think so.
>>But the *coupling* between receiver and parameter here is much stronger -
>>identity! - than a mere reference. And the intent of the requirement here -
>>as *I* read the standard - has been to have *no* coupling between parameter
>>and receiver here.
> 
> 
> This interpretation is clearly unreasonable.  I can see how one might
> reasonably interpret the identity coupling as a sort of indirect
> reference (though I suspect that what is meant instead is a reference
> chain),


> but you're ignoring the very important clause, "as a result of
> this message."  This coupling is not a result of the message at all.

This is true: I've overlooked that.

> Furthermore, consider the following:
> 
>   a := OrderedCollection with: 1.
>   b := OrderedCollection with: 1 with: a.
>   b removeAll: a.
> 
> I would certainly hope that any reasonable programmer would consider
> this perfectly sensible, and should remove 1 from b, leaving it with
> the single element a.  This is a direct reference that your reading of
> the standard would require to be illegal.  Fortunately, since it is
> clear that this reference is not a result of sending #removeAll:, it
> is, in fact, permitted by the standard.

Good example.

Thank you for the correction.


Greetings,

Stephan

<snipped>
-- 
Stephan Rudlof (sr@xxxxxxxxx)
   "Genius doesn't work on an assembly line basis.
    You can't simply say, 'Today I will be brilliant.'"
    -- Kirk, "The Ultimate Computer", stardate 4731.3