[Python-Dev] draft PEP: Trace and Profile Support for Threads

[Guido van Rossum]

> >> Seems to me that this is a good argument for module-level properties,
> >> BTW, or we require that all module attributes be set only through
> >> functions.
> > 
> > I'm not following.  What do you mean by module-level properties?
> 
> Data descriptors on module objects.

I promise you will never get these.  Modules are supposed to be robust
and simple.  If you want fancy, you can use classes and instances.

> Let's suppose we have, say, a BCD module.  For example, we want to
> set the "global" rounding state on a per-thread basis.  By
> definition, modules are singletons, so there needs to be a container
> within the module to hold the per-thread rounding state.  Question
> is, how/when do we update that container?  Currently, the only
> option is to require a user to call a function with the new setting
> as a parameter; I can imagine cases where it would be convenient to
> be able to simply set the module attribute, exactly the way we now
> permit with new-style classes.

Hm, why hide the mechanism?  I'd say let the BCD module get an options
object by explicitly asking for the current thread (or using a
higher-level per-thread data facility), and let the user make a
function call to set the state -- the function can request the
per-thread options object and update it.

--Guido van Rossum (home page: http://www.python.org/~guido/)