On Sun, 26 Aug 2012 16:12:40 -0400, Dennis Lee Bieber wrote: > On 26 Aug 2012 13:43:33 GMT, Steven D'Aprano > <steve+comp.lang.pyt...@pearwood.info> declaimed the following in > gmane.comp.python.general: > > > >> (In some older versions of Python, wildcard imports are allowed, and >> the function then falls back on a namespace instead of fixed locations. >> That is no longer the case in Python 3.2 at least.) >> > Must be really old:
Not really. You get a SyntaxWarning back to at least 2.2, but the fallback namespace behaviour does work through to 2.7: py> assert 'pi' not in globals() py> def test(): ... from math import * ... print pi ... <stdin>:1: SyntaxWarning: import * only allowed at module level py> test() 3.14159265359 What I didn't realise until just now is that it's a bit more complicated than that. Using import * in a function you can end up with two distinct sets of locals, those using numbered memory slots (effectively address- based), and those using a dict namespace. If you assign to a name in the function, it still gets turned into a memory slot rather than being in a dict. Decompiling the function shows that such local are still accessed using LOAD_FAST and STORE_FAST op- codes. (That's the case all the way back to Python 1.5 at least.) But if you *don't* assign to the name, Python uses LOAD_NAME instead, which searches namespace. In this case pi is not found in the global or built-in namespaces, so there must be a local, dict-based namespace in addition to the usual LOAD_FAST slots. Hence, two distinct sets of locals. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
