[Chicago] Import question

[Daniel Griffin]

That makes a lot of sense. I ended up splitting the db file in 2 so that the
parts that need the imports are separate from the parts that the imports
need.

Thanks,
Dan

On Mon, Dec 22, 2008 at 8:48 PM, Martin Maney <maney at two14.net> wrote:

> On Mon, Dec 22, 2008 at 06:58:42PM -0600, Daniel Griffin wrote:
> > I am having a problem with imports. I have 2 files, 1 which sets up
> > SQLAlchemy and maps the object and the other which imports the first so
> that
> > it can get a database connection.
> >
> > Example
> > file obj
> >
> > import db
> > class obj:
> >
> >
> > file db
> > from obj import obj
> > mapper(obj....)
> > Session() = scoped_session()
> >
> > python
> > from obj import obj
> > can't find obj
> >
> > I hope this makes sense, its twisting my brain around. Does anyone know
> what
> > I am doing wrong?
>
> >>> from obj import obj
>
> This requires module obj to be imported, of course.  During that
> import, before class obj is defined, module db has to be imported.
> during *that* import, an attempt is made to import obj and access the
> class obj... which doesn't yet exist.  Exception time.
>
> It's not that you can't import recursively, the problem is that you
> have to consider what you can actually access at the time it recurses.
> If class obj can be defined without referring to db, the easy fix would
> be to move that import below the class obj definition.  If you really
> cannot define class obj without having access to stuff in db which in
> turn requires the ability to instantiate class obj, there is no hope
> for this design.
>
> Think of it this way: how would you write it if there were only the
> obj.py file, and it had to contain everythig from both files as they
> are now.  How could you order things so that it would work that way?
>
> --
> We reject kings, presidents, and voting.
> We believe in rough consensus
> and running code. -- David Clarke
>
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