piaget-dev team mailing list archive

[Xavier Saint-Mleux <saintmlx@xxxxxxxxxx>]

Olivier Delalleau wrote:
> It sometimes happens that I want to run some Python program while
> within my piaget/piaget directory, and if it tries to import the 'math'
> module, it will import piaget.math instead of the standard math
> module... which does not work too well.
>
> Is there another solution besides renaming math? If not, we should
> probably try to avoid naming any submodule the same as an existing
> Python base module.

By default, Python looks in the current working directory first when
importing, so it is always best not to use Python from within the
directory of a package in order to avoid name clashes. 

A similar problem exists when importing piaget from its source
directory: it will import the "source" package instead of the installed
one and none of the compiled C++ extensions will be available.

This is not Piaget-specific.  For example, if you try to import Numpy
from its source directory, an ImportError is explicitly raised:

$ cd numpy-1.3.0/
$ python
Python 2.5.2 (r252:60911, Jul 31 2008, 17:28:52)
[GCC 4.2.3 (Ubuntu 4.2.3-2ubuntu7)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import numpy
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "[...]/numpy-1.3.0/numpy/__init__.py", line 121, in <module>
    raise ImportError(msg)
ImportError: Error importing numpy: you should not try to import numpy from
        its source directory; please exit the numpy source tree, and
relaunch
        your python intepreter from there.
>>>


HTH,


Xavier