Abstract Classes

[Tim Cook]

I am implementing a set of specifications that were designed to be OO
language neutral.

Several classes are specified as being abstract; so therefore there
should be no instances of them, correct?

However in the classes that are subclasses what is the correct way in
Python to implement them?
I am using the zope.interface module as well.

For example:

class IA(Interface):
   m = Int()
   p = TextLine()

class IB(Interface):

   x = Bool()
   s = Text()



class A(object):
""" This is an abstract class with attributes m is an int and p is a
string"""

   implements(IA)
   pass

class B(A):
  implements(IB)

  def __init__(self,m,p,x,s):
    m=m
    p=p
    x=x
    s=s


or should it be like:

class A(object):
""" This is an abstract class with attributes m is an int and p is a
string"""

   implements(IA)

   def __init__(self,m,p):
     m=m
     p=p


class B(A):
  implements(IB)

  def __init__(self,m,p,x,s):
    A.__init__(m,p)
    x=x
    s=s


or maybe even:

class B(A):
  implements(IB)

  def __init__(self,m,p,x,s):
    super(A.__init__(m,p))
    x=x
    s=s

Thanks for any pointers.

Tim


--
Timothy Cook, MSc
Health Informatics Research & Development Services
LinkedIn Profile:http://www.linkedin.com/in/timothywaynecook
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