[Help-smalltalk] OrderedSet (was Re: environment/shared pool search order?)

[Stephen Compall]

On Tue, 2007-04-10 at 08:06 +0200, Paolo Bonzini wrote:
> The best way to do so would be the other way round:
> subclass OrderedCollection, wrapping all the "add" methods
> with a test for inclusion (using the hashed collection),
> and redefining #includes: so that it uses the hashed
> collection.  This would have the advantage that you
> could use the same class for both OrderedSet and
> OrderedIdentitySet.

Since I wrote OrderedSet for the core as a subclass of
OrderedCollection, I thought I might ask what specifically would be more
useful:

1. An OrderedCollection that does not allow two "equal" elements
(at:put: fails if element is already present and not at that position,
add: ignores argument if already present).

2. A <Set> that remembers the order in which elements were added (the
OrderedCollection protocols missing from Set are self
shouldNotImplement)

The difference is that the attached follows 1 and supports all of
OrderedCollection's operations (forgive the usingSet: nonsense that is
just there until I come up with something better).  After writing them,
I thought that maybe they should not be supported at all (except for the
index = collection size case).

-- 
;;; Stephen Compall ** http://scompall.nocandysw.com/blog **
Failure to imagine vast possibilities usually stems from a lack of
imagination, not a lack of possibility.

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