Ray Schumacher wrote:
> What is the feeling on using "parent" in a class definition that class
> methods can refer to, vs. some other organization ?
> Should all relevant objects/vars just be passed into the method as needed?
> It seems like including "parent" in the class def is just like a class
> variable, which most do not recommend.
>
> An example:
> class LXSerial:
> def __init__(self, parent, debug=False):
> ...
> def connect(self, port, baud=9600, ptimeout=10):
> if self.debug:
> self.connectedPort = StringIO.StringIO(':A#')
> else:
> if self.parent.model=='LX200GPS': ptimeout = 240
> ...
>
> Ray
>
>
Passing parent instance into a class is perfectly legal and is
used extensively in modules like wxPython GUI. It isn't really
anything like a class variable as the instance is normally
passed not the class itself. Each instance can have different
attributes. So if you have many parents with many children this
can be an effective way to structure them.
I think it depends on how deeply nested things get and how many
parameters need to be passed. I've used it when I want to
nest my objects more than 2 deep and I must pass around lots of
attributes. I find it is easier to just look "upwards" into the
parent to get the attribute than to clutter up my argument list
passing arguments deeper and deeper into the class hierarchy.
It can simplify the argument lists quite a bit. Maybe others can
comment with their thoughts as well.
-Larry Bates
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