[Python-Dev] PEP-able

[M.-A. Lemburg]

Paul Prescod wrote:
> 
> PEP: ???
> Title: Computed Attributes
> Version: $Revision: 1.0 $
> Owner: paul@prescod.net
> Python-Version: 2.0
> Status: Incomplete
> 
> Introduction
> 
>     This PEP describes a feature to make it easier to use Python
>     attribute set/get/del syntax to fetch the results of a computation
>     or to invoke computation. This feature has been emulated using
>     __getattr__/__setattr__/__delattr__ but this approach suffers
>     severe usability and performance concerns.
> 
> Syntax
> 
>     Special methods should declare themselves with declarations of the
>     following form:
> 
>     class x:
>         def __get_foo__(self ): ...  def __set_foo__(self, value ): ...
>         def __del_foo__(self ): ...
> 
>     They are used like this:
> 
>     fooval=x.foo
>     x.foo=fooval+5
>     del x.foo

I don't get the point: how is this better than defining
explicit access methods ?

get_foo(self)
set_foo(self, value)
del_foo(self)

These not only define a distinct interface, but also provide
more flexibility, e.g. get_foo() could have a default argument.

-- 
Marc-Andre Lemburg
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