Borg Pattern Class usable from other classes?
ian at atlas.science-computing.de
Fri Oct 12 16:19:38 CEST 2001
Duncan Booth <duncan at nospamrcp.co.uk> wrote:
> If you run a.py as a script then it executes as the module '__main__'. This
> is why you can do the test for the current module name being '__main__'. If
> you import a from another module then it runs as the module 'a'. Even
> though both modules '__main__' and 'a' are executing from the same file
> they have completely separate namespaces.
> So when b imports a it is going to see a brand new Borg class, not the one
> you created in your __main__ script.
This makes it perfectly clear to me, thanks a lot!
> The solution is to put your Borg class in a separate module, or more
> generally never try to import anything from the __main__ script that you
> use to kick off the program.
That I found yesterday also, but without an idea why it helped.
Erik Max Francis wrote in <3BC5E0A7.41050647 at alcyone.com>:
>The sequence appears strange anyway. a.py defines the support classes
>and b.py defines the test harness, but the __main__ clause of a.py
>invokes the test harness? Why not put the test harness where it
>belongs, in b.py with the Test class? That will eliminate your
>recursive import problem.
Well, this was not about a test harness. The class got named Test
while I was trying to find a minimal case which shows the problem. I
use the Borg class to contain configuration information like username,
And only lead your singleton if it is not in the trump suit, because
that would be pointless.
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