Ray.Allen <ysj....@gmail.com> added the comment:
The 'as' trigger some more instructions after import, not just renaming the
loaded file name, to be specific in your example is, load attribute 'b' from
'a', and then load attribute 'c' from 'b'.
'import a.b.t' do import a.b.t and then just store 'a' in local namespace which
is a reference of module 'a'
while,
'import a.b.t as t' do import a.b.t and then load attribute 'b' from module
'a', then load attribute 't' from module 'b', finally store 't' in local
namespace as a reference of a.b.t
But at that time('import a.b.t as t'), the statement 'import a.b' in demo.py
hasn't finished executing yet, (because it triggers the statement 'import
a.b.c' in a/b/__init__.py, which then triggers the statement 'import a.b.t as
t' in a/b/c.py), along with the a/b/__init.py__.py file, although the module a
has been imported, but module 'b' hasn't finished importing, it't only put in
sys.modules, its module's code hasn't finishing executing(the code in
a/b/__init__.py). In this case the module 'b' is considered not finishing
importing, so it hasn't been put in module a's dict as an attribute yet.
So when the statement 'import a.b.t as t' executes in a/b/c.py, the module 'a'
hasn't the attribute 'b'. But after the statement 'import a.b' in demo.py, the
a/b/__init__.py file has complete executing, and the module b has finished
importing, module 'b' has been put in module a's dict, at this time, 'load
attribute b from a' is valid. So the import a.b as b in demo.py also works.
----------
nosy: +ysj.ray
_______________________________________
Python tracker <rep...@bugs.python.org>
<http://bugs.python.org/issue8389>
_______________________________________
_______________________________________________
Python-bugs-list mailing list
Unsubscribe:
http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
