Tricky Areas in Python

Alex Martelli aleaxit at yahoo.com
Tue Oct 25 16:54:55 CEST 2005


Fredrik Lundh <fredrik at pythonware.com> wrote:

> Alex Martelli wrote:
> 
> >> >     class Sic:
> >> >         def getFoo(self): ...
> >> >         def setFoo(self): ...
> >> >         foo = property(getFoo, setFoo)
> >
> > Sorry for skipping the 2nd argument to setFoo, that was accidental in my
> > post.  The problem here is: class Sic is "classic" ("legacy",
> > "old-style") so property won't really work for it (the setter will NOT
> > trigger when you assign to s.foo and s is an instance of Sic).
> 
> what's slightly confusing is that the getter works, at least until you attempt
> to use the setter:

Oh yes, that IS definitely contributing to the confusion -- which is
part of why I think it makes sense to claim this is a "tricky area".

> (a "setter isn't part of an new-style object hierarchy" exception would have
> been nice, I think...)

Agreed.  Alas, a bit too late now, I fear (until 3.0 when old-style goes
away) -- somebody might be (unwisely but "it-sort-of-works" style)
relying on this behavior.  Hmmm, maybe a WARNING could be given...


Alex



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