"Alex Martelli" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > John Nagle <[EMAIL PROTECTED]> wrote: > >> Marcin Ciura wrote: >> >> > Neither would I. I must have expressed myself not clearly enough. >> > Currently >> > x = y = z >> > is roughly equivalent to >> > x = z >> > y = z >> > I propose to change it to >> > y = z >> > x = z >> >> Actually, it is equivalent to >> >> y = z >> x = y > > Not really: > >>>> class chatty(object): > ... def __init__(self): self.__dict__['__hide'] = {} > ... def __setattr__(self, name, value): > ... print 'sa', name, value > ... self.__dict__['__hide'][name] = value > ... def __getattr__(self, name): > ... print 'ga', name > ... return self.__dict__['__hide'].get(name) > ... >>>> c = chatty() >>>> x = c.zop = 23 > sa zop 23 >>>> > > As you can see, there is no read-access to c.zop, which plays the role > of y there. > > > Alex
This is interesting: >>> class Test(object): ... def __getattribute__(self,n): ... print 'reading',n ... return object.__getattribute__(self,n) ... def __setattr__(self,n,v): ... print 'writing',n,v ... return object.__setattr__(self,n,v) ... >>> x=Test() >>> x.a=1; x.b=2; x.c=3 writing a 1 writing b 2 writing c 3 >>> x.a=x.b=x.c reading c writing a 3 writing b 3 >>> I wouldn't have expected "a" to be assigned first in a right-to-left parsing order. The result is the same in any case. -Mark T. -- http://mail.python.org/mailman/listinfo/python-list
