[Python-Dev] properties and block statement

[Antoine Pitrou]

Le mardi 18 octobre 2005 à 19:17 +0200, Antoine Pitrou a écrit :
> >     What would this mythical block statement look like that would make
> > properties easier to write than the above late-binding or the subclass
> > Property recipe?
> 
> I suppose something like:
> 
> class C(object):
>     x = prop:
>         """ Yay for property x! """
>         def __get__(self):
>             return self._x
>         def __set__(self, value):
>             self._x = x

An example of applicating this scheme to Twisted:

domain_name = "www.google.com"
reactor.resolve(domain_name):
    def callback(value):
        print "%s resolves to %s" % (domain_name, value)
    def errback(error):
        print "failed to resolve %s!"

And then in the Reactor class:

def resolve(self, name, @block):
    ...
    d = defer.Deferred()
    cb = block.pop('callback')
    if cb is not None:
        d.addCallback(cb)
    eb = block.pop('errback')
    if eb is not None:
        d.addCallback(eb)
    if block:
        raise ValueError("spurious blockargs: %s" %
            str(block))
    return d