[Python-Dev] decorators: If you go for it, go all the way!!! :)

[Simon Percivall]

On 2004-08-26, at 12.58, alex_nanou at cs.msu.su wrote:
> the inability to decorate anything but a function, is quite a 
> limitation,
> though I must agree that decorating classes is not such a common task, 
> but
> using the syntax to *decorate* attributes would indeed prove useful (in
> both the readability department and the uniformity of code)..
> [...]
>
> and here are a couple of usage examples:
> the desired decorator syntax:
> ---cut---
> class A(object):
>     @intonly
>     i = 123
>
> --uncut--
>
> the current usage syntax:
> ---cut---
> class A(object):
>     i = intonly(123)
>
> --uncut--

IMHO, this would be _bad_.

As I see it, the need for a special syntax for decoration, in this case 
a
prefix syntax, comes mainly from the fact that method/function and class
declaration is just that, declarations. You can only pass the entity to 
a
decorating function after it has been bound. Hence the irritating need 
to
type the entity name three times, once declaring, once re-binding and 
once
passing to the decorating function. This just isn't an issue here. If 
you
create an instance of some type, such as the integer literal in your
example, you can, just as you show, pass it to a function directly. 
This is
truly the best way, and the decoration is unnecessary.

Also, I don't agree it increases readability. The @ character marks
something special, something you might really need to see to understand
what is defined with a function/method or class. That's why re-binding
that entity afterwards isn't good enough: you might miss it. Again,
this isn't an issue here.

//Simon