On Tue, 03 Jan 2012 14:21:36 -0800, Peter wrote:
> I have a program that talks to a device via a serial interface.
> Structurally it looks like this:
>
> Program A -> module B -> Serial
I don't understand what this means. Program A points to module B, which
points to ... what is Serial? Where is it? Is it a class inside the
module, or another module?
> I want to add a protocol layer around the serial port without modifying
> any of the modules above and I want to be able to use BOTH cases of the
> program whenever convenient,
Where are you using them from? Program A, or another program?
I don't see any way to add the extra functionality to Program A without
modifying Program A. But if you're okay with that, here's a way to
conditionally define a class to use:
# inside Program A
import moduleB
if condition:
Serial = moduleB.Serial # I assume moduleB has a Serial class
else:
class Serial(moduleB.Serial): # subclass
def mymethod(self):
pass
connection = Serial(...)
> so at first it seemed like a simple case of
> sub-classing the Serial class and then (this is the problem) somehow use
> either the original serial class definition when I wanted the original
> program functionality or the new class when I wanted the extra layer
> present.
No problem. Here's another way to do it:
from moduleB import Serial as SimpleSerial
class ComplexSerial(SimpleSerial):
...
And now you can use both at the same time.
--
Steven
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