On Wed, Aug 05, 2020 at 03:35:15PM +0200, Marco Sulla wrote:
[Greg Ewing]
A considerable number of moons ago, I suggested that
@my_property fred = 42should expand to
fred = my_property("fred", 42)The point being to give the descriptor access to the name of the attribute, without having to repeat yourself.
[Dominik Vilsmeier]:
That should be possible by doing `fred = my_property(42)` and defining `__set_name__` on the `my_property` class.
Just because you define your own dunder method (which you shouldn't do, since dunders are reserved for the interpreter's use) doesn't make something which is a syntax error stop being a syntax error.
[Marco Sulla]
I suppose that what Greg Ewing suggests is a way to define a sort of custom simple statement.
For example, instead of the old print "Hello"
and the "new" print("Hello")
you could write
@print "Hello"
Perhaps you should re-read Greg's proposal again. I've left it quoted above. This is a proposal for decorator syntax, not a new way to call objects for their side-effects. If there's no assignment, it isn't going to work, it's still going to be a syntax error.
This would work:
@print word = "Hello"
but it would print "word Hello", and assign None to `word`.
So no, Greg's proposal is nothing like a "custom simple statement", it is a proposal for an extension of decorator syntax to simple assignments. Your version would be a syntax error, because there is no assignment and no target name.