[Python-Dev] Python 3 design principles

Robert Kern rkern at ucsd.edu
Wed Aug 31 23:00:08 CEST 2005

Oren Tirosh wrote:

> While a lot of existing code will break on 3.0 it is still generally
> possible to write code that will run on both 2.x and 3.0: use only the
> "proper" forms above, do not assume the result of zip or range is a
> list, use absolute imports (and avoid static types, of course). I
> already write all my new code this way.
> Is this "common subset" a happy coincidence or a design principle? 

I think it's because those are the most obvious things right now. The
really radical stuff won't come up until active development on Python
3000 actually starts. And it will, so any "common subset" will probably
not be very large.

IMO, if we are going to restrict Python 3000 enough to protect that
"common subset," then there's not enough payoff to justify breaking
*any* backwards compatibility. If my current codebase[1] isn't going to
be supported in Python 3000, I'm going to want the Python developers to
use that opportunity to the fullest advantage to make a better language.

[1] By which I mean the sum total of the code that I use not just code
that I've personally written. I am a library-whore.

Robert Kern
rkern at ucsd.edu

"In the fields of hell where the grass grows high
 Are the graves of dreams allowed to die."
  -- Richard Harter

More information about the Python-Dev mailing list