Versioning Libraries

[Richard Brodie]

"Peter Hansen" <peter at engcorp.com> wrote in message news:coog1l$mip$1 at utornnr1pp.grouptelecom.net...

> Python is exceptionally backwards compatible, so generally
> code from an older version will run unchanged on newer
> Pythons.

I'm just curious: why exceptionally? I like Python for a lot of
reasons but I wouldn't put API stability high on the list.
Not compared with a traditional language like C or Fortran,
anyway. Which languages go around breaking backwards
conmpatibility in a cavalier way?