Recursion problem

[Dennis Peterson]

Now I get it! I was thinking in C++, and this was driving me crazy. Thanks
very much Raymond!
-Dennis

"Raymond Hettinger" <python at rcn.com> wrote in message
news:ac7m0m$ndu$1 at bob.news.rcn.net...
> Hello Dennis,
>
> I suspect that you want a separate data array for each instance of
Compound.
> Right now, both c and d share the same list.  Separate them the way you
did
> with Simple.  This should run nicely:
>
> class Simple:
>     def __init__(self,x):
>         self.data = x
>     def getData(self):
>         return self.data
>
> class Compound:
>     def __init__(self):
>         self.data = []
>     def getData(self):
>         y = ""
>         for i in self.data:
>             y += i.getData()
>         return y
>
> def test():
>     a = Simple("hello")
>     b = Simple("goodbye")
>     c = Compound()
>     c.data.append(a)
>     c.data.append(b)
>     print c.getData()
>     d = Compound()
>     d.data.append(c)
>     print d.getData()
>
>
> Raymond Hettinger
>
>
> "Dennis Peterson" <denpeterson at yahoo.com> wrote in message
> news:ac7d2u02vgg at enews2.newsguy.com...
> > I'm trying to implement a basic Composite pattern. In the following
code,
> I
> > expect c.getData() and d.getData() to both return "hellogoodbye".
Instead,
> > on d.getData() I get stacktrace printing "y += i.getData()" repeatedly
> until
> > recursion depth exceeded. Why?
> >
> > I'm new to Python, running latest Windows version just downloaded.
> >
> > class Simple:
> >     def __init__(self,x):
> >         self.data = x
> >     def getData(self):
> >         return self.data
> >
> > class Compound:
> >     data = []
> >     def getData(self):
> >         y = ""
> >         for i in self.data:
> >             y += i.getData()
> >         return y
> >
> > def test():
> >     a = Simple("hello")
> >     b = Simple("goodbye")
> >     c = Compound()
> >     c.data.append(a)
> >     c.data.append(b)
> >     print c.getData()
> >     d = Compound()
> >     d.data.append(c)
> >     print d.getData()
> >
> >
>
>