On Thu, 11 Oct 2007 09:58:48 -0700, Dan Stromberg wrote: > On Thu, 11 Oct 2007 13:46:12 +0000, Marc 'BlackJack' Rintsch wrote: > >> On Thu, 11 Oct 2007 13:04:53 +0000, Artur Siekielski wrote: >> >>> 1. If I use instance field 'name' which is accessed directly by other >>> classes, >>> and later I decide to implement nonstandard getter, I must refactor >>> 'Person' class >>> and in some places change 'name' to '_name' (assuming this is now the >>> field's name). >>> The problem is that I cannot automatically change 'name' to '_name' >>> everywhere, because >>> in some places I want public property value (eg. validated and >>> formatted), and in other >>> places raw property value. >> >> So what? Otherwise you carry *always* the baggage of a public property >> and a private attribute whether you need this or not. At least for me it >> would be unnecessary in most cases. > > That "baggage" of carrying around "unneeded" methods is something the > computer carries for you - IE, no big deal in 99.99% of all cases.
It shows twice as much attributes if I inspect the objects and I don't know which are merely useless default getters and setters. And it is more and more complex code. Code can be cut down a bit by some metaclass magic but this brings in another complexity. > The "baggage" of possibly fixing (AKA "generalizing") how your attributes > are accessed is something you lug around while your deadline looms. Sorry I don't get it. If I want to customize the access to a "normal" attribute I simply turn it into a property. > Here's some code that defines such methods for you: > > #!/usr/bin/env python > > def gimme_set_get(foo, attribute): > lst = [ \ > 'def set_%s(self, value):' % attribute, \ > ' self._%s = value' % attribute, \ > 'def get_%s(self):' % attribute, \ > ' return self._%s' % attribute, \ > 'foo.set_%s = set_%s' % (attribute, attribute), \ > 'foo.get_%s = get_%s' % (attribute, attribute) \ > ] > s = '\n'.join(lst) > code = compile(s, '<string>', 'exec') > eval(code) > > class foo: > def __init__(self, value): > self.public_value = value > gimme_set_get(foo, 'via_accessor_method_only') > > f = foo(1) > f.set_via_accessor_method_only(1/9.0) > print f.get_via_accessor_method_only() > > print dir(f) And the benefit of this evil ``eval`` dance is exactly what!? Ciao, Marc 'BlackJack' Rintsch -- http://mail.python.org/mailman/listinfo/python-list