[Pythonmac-SIG] Re: Newbie path problem

[Jack Jansen]

On 26-feb-04, at 16:12, Christer Fernstrom wrote:

>>> Sorry, I'll try to make it clearer. The first module, Module-A, is 
>>> the main program module. It imports Module-B, which resides in the 
>>> same directory as Module-A. This directory, Directory-D, is not on 
>>> the PYTHONPATH. Using terminal, and positioned in any directory, I 
>>> can successfully invoke Module-A:
>>>  % python Directory-D/Module-A.py <paramters>
>>> Printing out the value of sys.path tells me that its first element 
>>> is "Directory-D", which explains why the import of Module-B works 
>>> fine.
>>>
>>> The problem occurs when I transform Module-A to an applet, using 
>>> BuildApplet. The import now fails, and looking at the Console window 
>>> I can see that sys.path now prints with a different value, and in 
>>> particular its first two elements are identical. They contain 
>>> "Directory-D/Module-A.app/Contents/Resources". It does not contain 
>>> Directory-D, which explains why the import fails.
>>>
>>> I could of course work around this in my code, but it doesn't seem 
>>> very clean to do it that way.
>>
>> Have you tried copying Module-B into Module-A.app/Contents/Resources 
>> ? Everything you need either needs to be findable from sys.path, or 
>> you will have yourself a location-dependent app (i.e. if you moved 
>> Module-A.app to any other location then it would no longer work).
>>
>> -bob
>>
> I assume it would work, but then this would depend on the fact that I 
> run Module-A as an applet and not a script. In my humble opinion, it 
> is the AppletBuilder's responsibility to initialise sys.path to 
> contain Module-A's source directory.

You're trying to do something BuildApplet wasn't intended for. 
BuildApplet takes a script that is self-contained (except for 
dependencies on the standard Python library) and packages it as an 
application. You can now move the resulting applet around on your disk, 
and even copy it to other machines with the same Python installation. 
Keeping a reference to the source directory isn't a good idea: it would 
break copying the applet to a different machine.

For more control over what exactly goes into the applet you want to use 
bundlebuilder. Unfortunately there isn't a good GUI for bundlebuilder 
just yet, so you have to use the command line tool.

Actually, BuildApplet is a remnant of MacPython-OS9, which had an 
all-singing-all-dancing application builder too: BuildApplication. 
BuildApplet was converted to OSX by using bundlebuilder under the hood, 
but BuildApplication wasn't. For 2.4 we should come up with a GUI tool 
that does both of these, and preferably the various intermediate 
possibilities as well.
--
Jack Jansen, <Jack.Jansen at cwi.nl>, http://www.cwi.nl/~jack
If I can't dance I don't want to be part of your revolution -- Emma 
Goldman