PATCH Re: [rucksack-devel] indexing issue?

[Cyrus Harmon]

Well, this is part of the story anyway. It still doesn't give the  
behavior I want on trying to make an instance with a duplicate value,  
but I think this is a step in the  right direction.

Also, instead of calling these slot-unique, slot-index, etc...  
shouldn't the convention be slot-definition-unique, etc...?

Cyrus

On Jan 10, 2007, at 1:13 PM, Cyrus Harmon wrote:

> Ok, I think I've figured out what's wrong with unique slots:
>
> --- mop.lisp	28 Nov 2006 15:25:57 -0800	1.11
> +++ mop.lisp	10 Jan 2007 13:12:19 -0800	
> @@ -250,6 +250,17 @@
>               (setf (slot-value effective-slotdef 'index)
>                     (slot-index (car index-slotdefs))))))
>
> +    ;; If exactly one direct slot is unique, then the effective  
> one is
> +    ;; too. If more then one is unique, signal an error.
> +    (let ((unique-slotdefs (remove-if-not #'slot-unique persistent- 
> slotdefs)))
> +      (cond ((cdr unique-slotdefs)
> +             (error "Multiple uniques for slot ~S in ~S:~% ~{~S~^,  
> ~}."
> +                    slot-name class
> +                    (mapcar #'slot-unique unique-slotdefs)))
> +            (unique-slotdefs
> +             (setf (slot-value effective-slotdef 'unique)
> +                   (slot-unique (car unique-slotdefs))))))
> +
>      ;; Return the effective slot definition.
>      effective-slotdef))
>
> I think c-e-s-d needs the previous patch in order to set the  
> effective-slot-definition's unique slot properly. I'm not sure it's  
> appropriate to signal an error, but it seems better than allowing  
> both :unique t and unique :no-error to be specified.
>
> Cyrus
>
>
> On Jan 9, 2007, at 11:43 PM, Cyrus Harmon wrote:
>
>>
>> On Nov 30, 2006, at 10:43 AM, Arthur Lemmens wrote:
>>
>>> Cyrus Harmon wrote:
>>>
>>>> What is the intended behavior of a unique slot?
>>>
>>> If a class has a unique slot, you (the programmer) promise that  
>>> there
>>> won't be two instances of that class which have a 'similar' value
>>> for that slot.  The definition of 'similar' depends on the kind of
>>> index you create (see the predefined index specs in index.lisp for
>>> some examples).
>>>
>>>> I'm able to make-instance new instances of a persistent class with
>>>> a duplicate slot value
>>>
>>> Yes, I think that Rucksack doesn't check for this at the moment.
>>> But it should have signalled an error, I think.
>>>
>>>> which seems fine
>>>
>>> I don't think so ;-)
>>
>> [some months pass...] so, yes, it seems like this should signal an  
>> error. and it looks like there's code in there to do that, but yet  
>> it doesn't seem to signal an error. Any idea why not?
>>
>> Thanks,
>>
>> Cyrus
>>
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>
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