Re: List container: Insert and Delete

[Ted Dennison<dennison@telepath.com>]

In article <3BF19106.5FF19B59@san.rr.com>, Darren New says...
>
>Ted Dennison wrote:
>> You had me, before you presented this example. :-)
>
>I don't follow. What's unreasonable about the example? It seems like a
>perfectly reasonable way of saying "does this come before that in the
>list", or saving positions to a stream, or printing something out for
>debugging, or whatever.

I didn't say it was unreasonable. Its just that its a pretty esoteric function.
I'll be charitable and say that for whatever wild reason, I have never required
such a thing from a List. Because of that, I am not currently convinced that
lots of others are out there who really do need it, therefore it wasn't the best
example that could have been chosen. I read from some other responses that I'm
not the only one in that boat.

Not that I'm saying  that there's nothing wrong with you if you need this or
some other esoteric function from a list from time to time. But I think all the
tools are already there to build your "Offset" function, and it won't really be
any slower than if one were provided for you. With the passive iterator, you'd
only need a one-line function, with the active perhaps 4 lines of code. When
that is the case, the general rule ought to be to leave the function out, unless
it is something so common that just about any disinterested observer would be
suprised to not find it in there. 

>Saying "we're not going to implement this operation because it's
>inefficient" doesn't sound like a good idea to me, is all.

Stated that way, I'd agree too. What I was suggesting was that stuff that can be
built w/ the other tools easily and is not O(1) (but *is* O(1) with the other
List type) perhaps should not be presented as a primitive. That way people are
encouraged to use the right tool (package) for the job. Again, this was just one
out of three positions I'd like to see discussed, as a middle ground between
total conformity between Bounded and Unbounded and total redesign. I frankly
could see a good case for any of the three.

>Someone will want to save positions. 
I believe you are most certianly right there, but no one has spoken up about it
yet.

---
T.E.D.    homepage   - http://www.telepath.com/dennison/Ted/TED.html

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