[sv-bc] RE: [sv-ec] Mantis 1702 unpacked concatenation of arrays - RESEND missing text

From: Jonathan Bromley <jonathan.bromley_at_.....>
Date: Tue Dec 04 2007 - 11:39:59 PST
Mike,

> I was the one who raised the possibility of 
[ref into a queue is effectively ref to a fixed-numbered element]
> basically to make the semantics simpler

Point taken, but I just don't see it as useful... sorry.
I can easily imagine wanting to have a reference that
continues to refer to the same data item as it moves
around in a queue; I can't for the life of me see what
I would do with a reference to "the third element in
a queue, whatever that might be holding at the time".

> The issue is that I don't think we have any
> definition now for what precisely a queue element is

Maybe I'm being really dumb here, but I don't see that
as a problem: a queue holds an ordered collection of
data items - there's nothing special about the elements
themselves, is there?  Of course I'm aware that this is
probably implemented as an array of references, or 
something like that; but users don't get to see that
at all.

> I think doing a) properly requires more work.

I thought it was OK provided you accept that writing
to the queue itself will invalidate references to 
the queue's original contents?

> Note that this behavior
[any write to a queue invalidates any references to 
its original contents] 
> means that the descriptions of queue methods
> will have to be changed so that they are no longer
> in terms of queue concat assignments.

Already done, in the latest proposal draft for 1702.
I just deleted the "equivalent to..." statements - 
I think the other descriptions are adequate as 
they stand.
--
Jonathan Bromley, Consultant

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Received on Tue Dec 4 11:40:26 2007

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