On 19/02/2008, goran at krampe.se <goran at krampe.se> wrote:
> Hi!
>
> Reinout Heeck <reinz at desk.org> wrote:
> > goran at krampe.se wrote:
> > > The *normal* way people usually do it thoiugh is to *not depend on the
> > > identity* of the Collection - different objects should typically not
> > > share the same Collection. And if you don't share - then the easy way
> > > out is to just do:
> > >
> > >     myCollection := OrderedCollection new "or whatever class you use"
> > >
> > > ...in order to empty it.
> >
> >
> > A word of caution: identity should be preserved in the 'normal' case,
>
> I agree. While I still think relying too much on identities is a
> dangerous practice.
>
> > replacing with another collection should be regarded as the exceptional
> > case. Your assertion that "different objects should typically not share
> > the same Collection." is only valid in limited cases.
>
> Well, I still stand by it as a general "nice rule". :)
>
> > I'm talking from my experience with building mvc-based apps on
> > VisualWorks. Code needs to be decoupled, ie 'model' objects and
> > collections should not know about the UI's that are coupled to them,
> > this is achieved with the various dependency mechanisms available in VW.
>
> I know, I used VW back in the 2.5-3.x days and while I first thought the
> adapter-frenzy was cool I later also started thinking it was
> over-engineered as hell. ;)
>
> > Changing identity of the collections will break this paradigm big time
> > (regardless of whether the dependents are managed in a global dictionary
> > or by the collection itself).
>
> Yes, if your adapters/UI components etc cling onto the collections
> themselves, then yes, you will be bitten big time. I still think that
> paradigm is fishy - but again, I only presented the way people
> *typically* go about this thing - I still of course would like to
> preserve identity and introduce #removeAll. It is better in all
> respects.
>
> If the *intent* is to "remove all elements" - then the message should
> state exactly that intent. Doing stuff like "aColl copy do: [:each |
> aColl remove: each]" is just plain dumb and silly, though it would
> probably qualify as a default implementation in class Collection. :)
>
It can be even shorter then:

Collection>>removeAll
   self removeAll: self copy

> regards, Göran
>
>


-- 
Best regards,
Igor Stasenko AKA sig.