My multi-year project -- started in 2006 according to my blog -- to rewrite import in pure Python and then bootstrap it into CPython as *the* implementation of __import__() is finally over (mostly)! Hopefully I didn't break too much code in the process. =)<div>
<br></div><div>Now this is "mostly" finished because the single incompatibility that importlib has is that it doesn't check the Windows registry for paths to search since I lack a Windows installation to develop and test on. If someone can tackle that issue that would be greatly appreciated (<a href="http://bugs.python.org/issue14578" target="_blank">http://bugs.python.org/issue14578</a>).</div>
<div><br></div><div>Next up is how to maintain/develop for all of this. So the Makefile will regenerate Python/importlib.h whenever Lib/importlib/_bootstrap.py or Python/freeze_importlib.py changes. So if you make a change to importlib make sure to get it working and tested before running 'make' again else you will generate a bad frozen importlib (if you do mess up you can also revert the changes to importlib.h and re-run make; a perk to having importlib.h checked in). Otherwise keep in mind that you can't use any module that isn't a builtin (sys.builtin_module_names) in importlib._bootstrap since you can't import something w/o import working. =)</div>
<div><br></div><div>Where does this leave imp and Python/import.c? I want to make imp into _imp and then implement as much as possible in pure Python (either in importlib itself or in Lib/imp.py). Once that has happened then more C code in import.c can be gutted (see <a href="http://bugs.python.org/issue13959" target="_blank">http://bugs.python.org/issue13959</a> for tracking this work which I will start piecemeal shortly).</div>
<div><br></div><div>I have some ideas on how to improve things for import, but I'm going to do them as separate emails to have separate discussion threads on them so all of this is easier to follow (e.g. actually following through on PEP 302 and exposing the import machinery as importers instead of having anything be implicit, etc.).</div>
<div><br></div><div>And the only outstanding point of contention in all of this is that some people don't like having freeze_importlib.py in Python/ and instead want it in Tools/. I didn't leave it in Tools/ as I have always viewed that Python should build w/o the Tools directory, but maybe the Linux distros actually ship with it and thus this is an unneeded worry. Plus the scripts to generate the AST are in Parser so there is precedent for what I have done.</div>
<div><br></div><div>Anyway, I will write up the What's New entry and double-check the language spec for updating once all of the potential changes I want to talk about in other emails have been resolved.</div>