[Python-Dev] Property syntax (Re: [Python-Dev] Extended Function syntax)

[Guido van Rossum]

> Guido:
> > Actually I was attempting to find a solution not just for properties
> > but for other situations as well.  E.g. someone might want to define
> > capabilities, or event handlers, or ...

[Greg]
> I'm not sure what a capability is, exactly, so I don't
> know what would be required to provide one.

Me neither. :-)  One person tried to convince me to change the
language to allow 'capclass' and 'capability' as keywords
(alternatives for 'class' and 'def').  In the end I convinced them
that 'rexec' is good enough (if the implementation weren't flawed by
security holes, all of which are theoretically fixable).  I *still*
don't know what a capability is.

> Or how an event handler differs from a method, for that matter.

Probably by being hooked up to an event loop automatically.

> But anyway, here's another idea:
> 
>   def foo as property:
>     def __get__(self):
>       ...
>     def __set__(self, x):
>       ...
> 
> which would be equivalent to
> 
>   foo = property(<dict-from-the-suite>)
> 
> or perhaps
> 
>   foo = property(<thunk-doing-the-suite>)
> 
> You might also want to allow for some arguments somewhere
> (not sure exactly where, though).

I don't like things that reuse 'def', unless the existing 'def'
is a special case and not just an alternative branch in the grammar.

--Guido van Rossum (home page: http://www.python.org/~guido/)