Question

In a blog post analyzing Python PDF libraries, S.Lott makes the following comment:

Here’s one example of remarkably poor programming:

#Connect the parser and document objects.    
parser.set_document(doc)    
doc.set_parser(parser)

Only one of these two is needed; the other is trivially handled as part of the setter method.

What is the a Pythonic way of doing this via the setter method?

Answer 1

class Parser(object):
    def set_document(self, doc):
        doc.set_parser(self)
        # whatever

Though in practice, I would redesign the document and parser classes to avoid circular references. Not only do they add conceptual complexity, they interfere with garbage collection as well unless weak references are used.