Deciding inheritance at instantiation?

[Steven W. Orr]

On 8/3/2012 4:48 PM, Tobiah wrote:
> I have a bunch of classes from another library (the html helpers
> from web2py). There are certain methods that I'd like to add to
> every one of them. So I'd like to put those methods in a class,
> and pass the parent at the time of instantiation. Web2py has
> a FORM class for instance. I'd like to go:
>
> my_element = html_factory(FORM)
>
> Then my_element would be an instance of my class, and also
> a child of FORM.
>
> I started messing with decorators, but it became difficult
> for me to visualise how to do this.
>
> Thanks!
>
> Toby

Your class inherits from whatever is in the class statement.

class Foo(object):
     pass

Here, Foo inherits from object, but you can replace object with any tuple of 
classes which can be redefined before instantiation.

class Base1(object):
     pass

class Base2(object):
     pass

Now we can define Foo2 to inherit from something that better be a tuple of 
classes at instantiation time.

class Foo2(bases):
     pass

bases = (Base1,)

foo2 = Foo2() # foo2 is a Foo2 which inherits from Base1.

bases = (Base1, Bace2)

foob1b2 = Foo2() # foob1b2 is a Foo2 which inherits from Base1 and Base2.

Who was it who said: "Give a man a shovel and he'll dig himself one helluva hole"?

-- 
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