[Newbies] reimplementing #= and #hash
Janko Mivšek
janko.mivsek at eranova.si
Sun Sep 23 13:27:58 UTC 2007
Hi Ching,
#= is test for equality while #== is test for identity. What do you
probably want is to override #= to compare two PoolQueues if they are
equal or not. But what "equal" means in your case is on you to define.
Maybe something like this:
PoolQueue>>= anotherPoolQueue
^(self member = anotherPoolQueue member)
and: [self processor = anotherPoolQueue member]
But be sure that also member and processor instvars understand #= in a
correct way. All numbers, strings, symbols etc. understand equality as
expected.
I hope this helps a bit.
Janko
Ching de la Serna wrote:
> Hi List,
>
> I have a Class PoolQueue which has instvars 'member' and 'processor'. I
> find that an instance of PoolQueue when placed in an OrderedCollection
> can no longer be considered equal. I suppose I have to reimplement #=
> and #hash to allow PoolQueue instances to be compared.
>
> My problem: how do I implement #hash? Or stated another way, what does
> #hash accomplish?
>
> Thanks in advance.
>
> Ching.
>
--
Janko Mivšek
AIDA/Web
Smalltalk Web Application Server
http://www.aidaweb.si
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