Possible improvement to slice opperations.

[Patrick Maupin]

> After considering several alternatives and trying out a few ideas with a
>   modified list object Bengt Richter posted, (Thank You), I think I've
> found a way to make slice operation (especially far end indexing)
> symmetrical and more consistent.

I don't know that it makes it more consistent.  I could be persuaded,
but it would have to be by real-life examples with calculated slice
indices and stride.  I do this thing all the time, and find the current
rules simple and very consistent.  Occasionally, I might wish that
things were a little different, but there is always a workaround.  I
would have to see some real code examples, of sufficient scope to see
that there are fewer workarounds with this proposal than with the
current implementation.

FWIW, there is a reasonable workaround for the case where the indices
might be negative and you would like zero or greater to mean 'end of
list'.  If "x" is the index variable, you can use the expression (x<0
and x or None) for the index value in the slice.  If you find yourself
doing this often, you can write a little function for it -- def
EndIndex(x): return x<0 and x or None.

But in real code, I fear you might need a similar helper function for
similar issues with your change.  I just don't know what those are
without more thought.

Regards,
Pat