Terry Reedy wrote: > "Brock Filer" <[EMAIL PROTECTED]> wrote in message > news:[EMAIL PROTECTED] > >>countries['us']['Colorado']['Denver']['@population'] >> >>This is going to be used in user-input formulae, so I'm willing to do a >>lot of work for minor beautifications. I'd like to be able to say (I >>know, the quotes are still ugly, but at least you save a bracket): >> >>countries/'us'/'Colorado'/'Denver'/'@population' >> >>That's easy to do with a __div__ method, but it only works for getting, >>not setting or deleting. >> >>I'd appreciate any thoughts on this problem. > > > I personally would first try to dump the quotes and use standard > attributes -- countries.us.Colorado... --
<aol/> > and the __get/set/delattr__ methods. > >>I keep thinking descriptors might be involved somehow in the solution, >>but I may be on a completely wrong track. > > > As far as I know, 'descriptor' is a behind-the-scenes concept, not > something you directly program with. Perhaps you meant 'property'. Properties are just syntactic sugar for a possible use of descriptors. A descriptor is just an object that follows a specific protocol (__get__, __set__, __del__) and is used as an attribute or method (the difference is very thin) of another object. You'll find all the relevant doc on python.org. > However, properties are fixed in number when you create the class. Dynamically adding attributes to an object (or a class - which is just another object) is not a problem. <op> If what you need is to provide an higher level view of your data, descriptors may be a good choice. I used them that way for a higher-level ldap API, where the class representing the LDAP object mainly stores the raw result (as returned by python-ldap) of the ldap query and uses descriptors to provide controlled (an simpler) access to the data. You may also want to read a recent thread here about descriptors: http://groups.google.fr/group/comp.lang.python/browse_frm/thread/6159fa26439b9ba5/0ad621b88a752b47 </op> -- bruno desthuilliers python -c "print '@'.join(['.'.join([w[::-1] for w in p.split('.')]) for p in '[EMAIL PROTECTED]'.split('@')])" -- http://mail.python.org/mailman/listinfo/python-list
