Diego Ballve wrote:
> Farrukh Najmi wrote:
>
>> Richard Martell wrote:
>>
>>> 5 [ADVISORY] In 2.8.1 perhaps change values to type Set<LongName>
>>> instead of Bag, since duplicate values don't appear to be meaningful
>>> in this context.
>>
>>
>>
>> Duplicate for values of a Slot do make sense. For example lets say
>> the Slot values store the Gender of each student in a class. I know
>> it is a dumb example but thats the best I can think of at present.
>> Suggest no change.
>
>
> Set, Bag or Sequence? I'd rather have sequence there, since it is more
> powerful than Set or Bag (i.e., you can represent a Set or a Bag in a
> Sequence but not the other way; you can randomize the order of an
> ordered collection after you get it, but it might not be possible to
> reorder an unordered collection to the same order it had on creation
> time).
+1
Diego makes an excellent point. Set or Bag do not maintain order but
Sequence does and sequence is often important in Slot values. BTW here
is a brief definition borrowed from [1] of each in case it is not clear:
Set: An object of class *set of* /X/ holds an unordered collection of
objects of class /X/ with duplicates prohibited.
Bag: An object of class *bag of* /X/ represents a similar collection
except that duplicates (and multiple instances in general) are permitted.
Sequence: An object of class *sequence of* /X/ is like a *bag of */X/
except that it is ordered, so we can enquire what value is at a
particular position in the sequence (just like indexing into an array).
[1] http://www.eschertech.com/tutorial/chapter2/class_collection.htm
I propose we accept teh change to use Sequence instead of Bag or Set in
draft 03
>
> We have discussed this about a year ago, I think, and by that time the
> use-case I had was that my value was longer than LongName, so I
> created extra logic in the client to break the value into many
> LongName (there's a flaw for searches, for instance, but anyway). For
> that I needed the registry to keep the order and not to return the
> objects in random order.
>
+1
Order is important for Slot values in many cases (including one above)
and does not hurt where it is not important.
--
Regards,
Farrukh
