[Python-Dev] Should there be a way or API for retrieving from a code object a loader method and package file where the code comes from?

[rocky at gnu.org]

Paul Moore writes:
 > 2008/12/23 Rocky Bernstein <rocky at gnu.org>:
 > > Now that there is a package mechanism (are package mechanisms?) like
 > > zipimporter that bundle source code into a single file, should the
 > > notion of a "file" location should be adjusted to include the package
 > > and/or importer?
 > 
 > Check PEP 302 (http://www.python.org/dev/peps/pep-0302/) specifically
 > the get_source (optional) method. 

Yes, that's one of the things I was thinking when I wrote:

  As best as I can tell, PEP 302 which discussed importer hooks and
  suggests a standard way to get file data.

And by "suggests" I meant was implying that yes I know this is
optional.


 > It's not exactly what you describe,
 > but it may help. 

Yes, it's not exactly what is desired. 

 > Please note that it's optional - if you loaded the
 > code from a zipfile containing only bytecode files, there is no source
 > to get, so you have to be prepared for that case. But if the source is
 > available, this should give you a way of getting to it.

What is wanted is a uniform way get and describe a file location
from a code object that takes into account the file might be a member
of an archive. 

Are there even guidelines for saying what string goes into a code
object's co_filename? Clearly it should be related to the source code
that generated the code, and there are various conventions that seem
to exist when the code comes from an "eval" or an "exec". 

But empirically it seems as though there's some variation. It could be
an absolute file or a file with no root directory specified. (But is
it possible to have things like "." and ".."?). And in the case of a
member of a package what happens? Should it be just the member without
the package? Or should it include the package name like
   /usr/lib/python2.5/site-packages/tracer-0.1.0-py2.5.egg/tracer.py ? 

Or be unspecified? If left unspecified as I gather it is now, it makes
it more important to have some sort of common routine to be able to
pick out the archive part in a filesystem from the member name inside 
the archive.


 > 
 > Paul.
 >