[Python-Dev] Declaring setters with getters

[glyph at divmod.com]

On 02:01 pm, guido at python.org wrote:
>On 10/31/07, glyph at divmod.com <glyph at divmod.com> wrote:
>>As long as we're all tossing out ideas here, my 2¢.  I vastly prefer
>>this:
>> >>        @property.set
>>to this:
>> >      @property.set(attribute)

>I don't approve of it. It has always been and will always
>continue to be my position that these are semantically unkosher,
>because it means that you can't wrap them in convenience functions or
>invoke them in different contexts, and that means that the semantics
>are hard to explain.

Point taken.
>If you really want another argument, repeating the property name
>actually does have an additional use case: you can have a read-only
>property with a corresponding read-write property whose name differs.

I don't actually have this use-case, but it does make the actual 
semantics of the provided argument a bit clearer to me.  It's not an 
implementation detail of fusing the properties together, it's just 
saying which property to get the read accessor from.

This is a minor nit, as with all decorators that take an argument, it 
seems like it sets up a hard-to-debug error condition if you were to 
accidentally forget it:

    @property
    def foo(): ...
    @property.set
    def foo(): ...

would leave you with 'foo' pointing at something that wasn't a 
descriptor at all.  Is there a way to make that more debuggable?