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Import a module from a non-file?

David Boddie davidb at mcs.st-and.ac.uk
Fri Oct 17 18:57:54 EDT 2003 
Alex Martelli <aleax at aleax.it> wrote in message news:<sAUjb.7504$e5.250987 at news1.tin.it>...
> Petri Savolainen wrote:
> 
> > I was trying to roll my own python code importer, but in the end, it seems
> > that no matter what you try, it is always necessary to supply a REAL file
> > object for python lower-level import machinery to work. Is this really
> > true? Or did I miss something?
> 
> No, it's not true.  Read PEP 302, http://www.python.org/peps/pep-0302.html ,
> for details.

That's only for Python 2.3 and later, though, isn't it? I ran into this problem
using Python 2.2 with the ihooks and imp modules. I don't remember exactly
which part of the infrastructure was insisting on file objects but the following
lines from Python/import.c in the Python 2.3 source distribution would appear
to be relevant:

    /* First check that there's an open file (if we need one)  */
    switch (type) {
    case PY_SOURCE:
    case PY_COMPILED:
        if (fp == NULL) {
            PyErr_Format(PyExc_ValueError,
               "file object required for import (type code %d)",
                     type);
            return NULL;
        }
    }

I really should investigate the new import mechanism. In the meantime, it's good
to know that the alternative import hook solutions still work with Python 2.3.

David
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