Design: Idiom for classes and methods that are customizable by the user?

[dieter]

Dirk Bächle <tshortik at gmx.de> writes:
> ...
> My questions
> ============
>
> - Is this a good approach, that I could use for other parts of the architecture as well, e.g. the Node class mentioned above?

You might look at the "adpater" pattern.

It is heavily used in Zope - and there looks something like:

  * components are abstracted by interfaces (--> "zope.interface")

  * where flexibility is needed, the code looks like
    
      component = queryAdapter(<context>, interface, default=...)

    or

      component = queryUtility(interface, default=...)

    to get a component implementing "interface".

    (utilities are in some way adapters for "None", i.e.
    those independent of a context)

  * there is an adapter registry, 
    its content is specified either via an XML specification file
    or via Python code