Light slices + COW

[bearophileHUGS at lycos.com]

David:

> What do you mean by best possible? Most efficient? Most readable?

What's a good wine? It's not easy to define what's "good/best". In
such context it's a complex balance of correct, short, fast and
readable (and more, because you need to define a context. This context
refers to Psyco too).


> And why don't you use islice?

You are right, but the purpose of light slices that I have suggested
is to avoid using islice so often. And currently Psyco doesn't digest
itertools well.


> D compiles to efficient machine code so Python is at a disadvantage
> even if you use the same syntax (see my first example). You can make
> the Python version faster, but beware of premature optimization.

This time I don't agree with this "premature optimization" thing. My
original Python version is just 5 lines long, it's readable enough,
and it's a part of a large library of mine of similar functions, they
must be fast because I use them all the time as building blocks in
programs.


> What I'dlike to see is a rope[1] module for Python.

People have already suggested it, and there's even an implementation
to replace Python strings. It was refused because... I don't know why,
maybe its implementation was too much more complex than the current
one, and it wasn't faster in all situations (and I think Guido wants
data structures that try to replace the basic built-in ones to be
faster in all situations and user-transparent too).

Bye,
bearophile