[Python-Dev] requirements for moving __import__ over to importlib?

[Terry Reedy]

On 2/8/2012 11:13 AM, Brett Cannon wrote:
> On Tue, Feb 7, 2012 at 22:47, Nick Coghlan <ncoghlan at gmail.com

>     I'm not sure such an addition would help much with the base
>     interpreter start up time though - most of the modules we bring in are
>     because we're actually using them for some reason.

> It wouldn't. This would be for third-parties only.

such as hg. That is what I had in mind.

Would the following work? Treat a function as a 'loop' in that it may be 
executed repeatedly. Treat 'import x' in a function as what it is, an 
__import__ call plus a local assignment. Apply a version of the usual 
optimization: put a sys.modules-based lazy import outside of the 
function (at the top of the module?) and leave the local assignment "x = 
sys.modules['x']" in the function. Change sys.modules.__delattr__ to 
replace a module with a dummy, so the function will still work after a 
deletion, as it does now.

-- 
Terry Jan Reedy