Re: Extending Methods Vs Delegates

vbgunz enlightened us with:
I hope I've made some sense with this question. I ultimately wish to
know just one real thing. Regardless of the name of the second
example above, what is the purpose of calling a sub class method
from a super class instance? What is the application to such a
design?

I've seen this style of programming before, in wxWidgets. The
constructor of a class does various things. This is roughly what
happens:

class wxSomeClass(wxParent):
def __init__(self, *args, **kwargs):
# Do various things

if not self.OnInit():
raise RuntimeError("Initialization failed")

# Do other things that need to be done after custom
# initialization

def OnInit(self):
return True

This makes it easier to simply provide custom initialization, without
having to redo everything in __init__. Calling the superclass'
function is fine if you want to add behaviour before and/or after
calling it. This example however lets you customize behaviour that's
put in the middle of the __init__ function.

Maybe an example will help?

I hope so :)

Sybren
--
The problem with the world is stupidity. Not saying there should be a
capital punishment for stupidity, but why don't we just take the
safety labels off of everything and let the problem solve itself?
Frank Zappa
.

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