Hi, Here's a framework for the questions: --- In a module, part of an API --- class Basis ( object ): def foo ( self, arg ): pass
--- In user's own code --- class Child ( Basis ): def foo ( self, not, sure ): ... Question 1: Given that the user of the API can choose to override foo() or not, how can I control the signature that they use? In the example the user has chosen bad arguments and Python will complain, but it's describing the sig of the *overridden* method and not the one in the parent class. Is there some way I can control the error message to make it clear to the user that they are using the signature of foo() incorrectly? Question 2: Say I am in class Basis, doing a loop and I have a list of Child objects. I want to run the foo() method for each one that *has* a foo() method. i.e. user has done this: class Sam ( Child ): ... *Sam does not define foo() class Judy ( Child ): def foo ( self, arg ): ... * Judy does define foo() Instances of Sam and Judy have been put into the list (within the instance) of Basis. I want Basis to detect that Judy has foo() and run it. I can handle question 2 by using a flag that must be set by the user. Something like: class Judy ( child ): def __init__( self ): self.pleaseCallFoo = true And now, Basis can check for that var and only then call foo(), but this is ugly and means more for the user to learn API-wise. Any ideas? /d -- http://mail.python.org/mailman/listinfo/python-list
