[REBOL] Re: Millennium + 1 ...
From: g:santilli:tiscalinet:it at: 5-Jan-2001 19:19
Hello Elan!
On 05-Gen-01, you wrote:
E> however, the way it is implemented is more consistent for a
E> different reason.
I'm not sure about this. The current implementation is probably
closer to the human way of thinking, but it can introduce subtle
problems. I'm not saying this is an important problem, and the way
it is worked for me since REBOL was released.
E>>> a: [1 2 3 4] ;- (1)
E>>> pick a 0
E> == none
E>>> insert a [-4 -3 -2 -1]
E>>> a: skip a 4
E>>> a
E> == [1 2 3 4]
E>>> pick a 0 ;- (2)
E> == none
The two give different results anyway if you use an index lesser
than zero:
>> a: [1 2 3 4]
== [1 2 3 4]
>> pick a -1
== none
>> a: insert a [-4 -3 -2 -1]
== [1 2 3 4]
>> pick a -1
== -1
E> (1) and (2) should be equivalent and they currently are.
I'd prefer:
>> a: [1 2 3 4]
== [1 2 3 4]
>> pick a 0
== none
>> a: insert a [-3 -2 -1 0]
== [1 2 3 4]
>> pick a 0
== 0
E> you were to introduce 0 as the position that precedes the
E> current position of the block, then (1) and (2) would not be
E> equivalent and that would be confusing.
I don't agree here. You get NONE if the position 0 does not exist.
With the current implementation it just never exists...
E> Using whole numbers instead of natural numbers for indexing a
E> block would be less user-friendly, because for the second
E> element to be located at index 1 (etc.) is counter-intuitive.
I wouldn't want that to happen. I like the way it is now, but not
taking 0 into account COULD introduce problems. It never did for
me, tough, and I agree that -1 is a more natural way to get the
position before the current one.
Regards,
Gabriele.
--
Gabriele Santilli <[giesse--writeme--com]> - Amigan - REBOL programmer
Amiga Group Italia sez. L'Aquila -- http://www.amyresource.it/AGI/
