backward/forward compatibility in PYTHON?

[holger krekel]

Attila Horvath wrote:
> Dear PYTHON community,
> 
> I'm new to PYTHON but am considering it for a new project development. As
> with any new language system I have a key concern:
> 
> 	How is backward (and forward) compatibility resolved in PYTHON?

In many ways :-)

backward compatibility:

- several years (commonly 2) of fading out deprecated features.

- Deprecation warnings if a feature could be removed in the 
  next version.

- if you know you are using e.g. python2.2 features you might
  want to code a one-line assertion like

    asssert(sys.version_info[:2]>=(2,2))

- 'good practices' like not relying on the current cvs python
  or weird sideeffects :-)

forward compatibility:

- new features are introduced via the

      from __future__ import xyz 

  construct. This keeps your code at least parsable and usually
  semantically the same. 

- it should take two major releases to break old code
  if the old code had no DeprecationWarnings. 

Also if you want something to work from python1.5.2 to python2.3 
you may have to learn about the common feature set of these 
versions. 

python3000 (or python3) may be a completly different matter of course :-)

    holger