[Python-mode] [Bug 450552] [NEW] python-mode breaks for python 3

[Andreas Roehler]

Rustom wrote:
> Public bug reported:
> 
> python 3 has removed execfile
> This makes python-mode stop working
> 
> In function py-execute-file changing the line
> 
> (cmd (format "execfile(r'%s') # PYTHON-MODE\n" filename)))
> 
> to
> (cmd (format "exec(open(r'%s').read()) # PYTHON-MODE\n" filename)))
> 
> seems to solve the problem
> 
> ** Affects: python-mode
>      Importance: Undecided
>          Status: New
> 



IMO it's not to cure by changing a line in general.

More bugs will be around due to different flavours of python.

Versions of python 2.4.+ are in use still AFAIK.
2.5.+ or 2.6.+ will remain widely used

Will a single python-mode be able to cope with this differences?

IMHO: yes, however it must to address some issues.

Herewith some outlines what seems necessary:

- specifying by a variable the version where edits are for  (customizable)

- some guessing, which python-version might be in used, if user didn't set it

- displaying python-versions-variable in mode-line

- auto-adapting code, editing and execution resp. to the mentioned version.

- possible switch between versions-specifics, updating the modeline etc.


Introducing a first item in this line might read:

(defcustom py-adressed-python-version ""
  "*With different Python versions, changes have been made, which affect python execution as editing likewise.
If a version is specified here, python-mode will adapt its proceeding to it.
Otherwise python-mode will try some guess from the installed system.
You may switch the addressed python-version with M-x py-switch-addressed-version during your emacs-session. "
  :type 'string
  :group 'python)

Any hints, objections, ideas?

Thanks!


Andreas

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