[Distutils] Install time prefixes and data files

[Wolodja Wentland]

On Fri, Nov 13, 2009 at 21:36 +0900, David Cournapeau wrote:
> On Fri, Nov 13, 2009 at 7:38 PM, Wolodja Wentland
> <wentland at cl.uni-heidelberg.de> wrote:

> > Could you elaborate on this idea please? Do you mean that megabars
> > plugins are shipped in a different distribution than megabar itself?
> 
> Yes. Imagine that I create a library, which includes a firefox plugin
> in python. I need to differentiate between what will end up in firefox
> and the rest.

I can certainly see the need for this and would be +1 on this idea.

One way to do this could be:

In megabar:

setup(
    ...
    custom_prefixes=[
        ('$plugins', '$purelib/plugins'),
        ('$foo', '$base_prefix/foo'),
        ...
        ],
    ...
    data_files=[
        ('$plugins', 'plugins/standard_plugin.py'),
        ...
        ]
    )

And in megabar-plugins:

setup(
    ...
    data_files=[
        (pkgutil.get_prefix('megabar', '$plugin'),
        'plugins/additional_plugin.py'),
        ...
        ]
    )

You could use a standard prefix if megabar does not define a $plugin
custom prefix within megabar-plugins, which might even be the default if
introduction of custom_prefixes is not accepted/ok.

I think we need to:

* compile a list of standard prefixes and their default values on all
  platforms. I still like the idea to be able to modify these *only* by
  setting environment variables, so it would look something like this:

  stdprefix1 = os.environ.get('PYDIST_STDPREFIX1', 
                              distutils.sysconfig.get_std_prefix('stdprefix1'))

  Create this list on a wiki? 

* Define an API that clarifies how to query this information:
    
    - within setup.py
    - at built time
    - at runtime
    - ... ??

Suggestions? Corrections? Better ideas? I am just brainstorming...

-- 
  .''`.     Wolodja Wentland    <wentland at cl.uni-heidelberg.de> 
 : :'  :    
 `. `'`     4096R/CAF14EFC 
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