[Squeak] Newbie permutations
Andrew C. Greenberg
werdna at mucow.com
Wed Apr 10 02:15:35 UTC 2002
Could be. On the other hand, the utility of #permutations is entirely
unclear to me. Even for small collections, the number of permutations
gathered rate to be fairly large.
On Tuesday, April 9, 2002, at 06:48 PM, Bijan Parsia wrote:
> On Tue, 9 Apr 2002, Andrew C. Greenberg wrote:
>
>> It is an implementation concern that should probably be documented. I
>> imagine it was done this way because it would be inefficient for
>> applications where copies are not required to have the method make
>> copies in each instance.
>
> Given that the selector is #permutationsDo:, it's perhaps worth having a
> separate method, #permutations, which would produce a collection of the
> distinct permuations. Then idioms like foo permutations select:...et al
> would work as expected.
>
>> On Tuesday, April 9, 2002, at 03:30 AM, Avi Bryant wrote:
>>
>>> On Tue, 9 Apr 2002, Duane Maxwell wrote:
>>>
>>>>> | foo |
>>>>> foo := OrderedCollection new.
>>>>> #(1 3 5) permutationsDo: [:each | foo add: each].
> [snip]
>
> Cheers,
> Bijan Parsia.
>
>
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