[Python-ideas] breaking out of module execution

[Jim Jewett]

On Wed, Apr 25, 2012 at 5:52 AM, Nick Coghlan <ncoghlan at gmail.com> wrote:

> ... tackle the problem of choosing between multiple
> implementations of a module at runtime ...

I like the idea, but I'm not sure I would like the result.

The obvious path (at least for experimenting) is to replace the import
statement with an import function.

(a)  At the interactive prompt, the function would return the module,
and therefore allow it to be referenced as _.  (I don't always
remember the "as shortname" until I've already hit enter.  And often
all I really want is to see help(module), but without switching to
another window.)

(b)  The functional interface could expose a configuration object, so
that in addition to deciding between alternate implementations, a
single implementation could set up objects differently.  (Do I really
need to define that type of handler?  What loggers should I enable
initially, even while setting up the rest of the logging machinery?
OK, let me open that database connection before I define this class.)

These are both features I have often wanted.  But I don't want to deal
with the resulting questions, like "Wait, how can that logger not
exist?  Oh, someone else imported logging first..."

And I'm not sure it is possible to get the freedom of (b) without
those problems, unless modules stop being singletons.

-jJ