[Python-Dev] method decorators (PEP 318) (original) (raw)

Robert Brewer fumanchu at amor.org
Fri Mar 26 12:57:54 EST 2004

Skip Montanaro wrote:

Guido> (2) Invent some other notation for setting function attributes as Guido> part of the function body, before the doc string even.

Guido> For (2) I am thinking aloud here: Guido> def foobar(self, arg): Guido> @author: "Guido van Rossum" Guido> @deprecated Guido> pass It's a shame that there's no good way to define function attributes already. Aside from the fact that this is different than the other form of "decoration", it's also different than setting attributes for classes. Rather than invent a unique syntax I'd prefer to either use a decorator function or suffer with tacking them on at the end: def foobar(self, arg): pass foobar.author = "Guido van Rossum" foobar.deprecated = True

Agreed. There are enough mechanisms to alter an object's attribute dict. I'd rather not introduce another one, preferring instead to stick to "object.attr = value"--in this example, "foobar.deprecated = True". Where that declaration goes is fungible.

Using the proposed decorator syntax with the decorator after the arglist with a little judicious indentation I can make it look sort of like what you're after:

def foobar(self, arg) [attributes( author = "Guido van Rossum" deprecated = True )]: pass Another possibility would be to overload def: def foobar(self, arg): def author = "Guido van Rossum" def deprecated = True pass

I'd still prefer a dot. How about:

def foobar(self, arg):
    def.author = "Guido van Rossum"
    def.deprecated = True
    pass

?

However, the idea of putting such attributes at the same level as the rest of the function block is ugly to me--newbies are going to go mad the first few times, trying to figure out when such statements are evaluated. Such statements IMO need their own "container", whether that's a block:

def foobar(self, arg):
    attributes:
        author = "Guido van Rossum"
        deprecated = True
    pass

...or a list:

def foobar(self, arg) [attributes(
    author = "Guido van Rossum"
    deprecated = True)]:
    pass

...or within the declaration:

def foobar(self, arg) having (author = "Guido van Rossum",
                              deprecated = True):
    pass

Robert Brewer MIS Amor Ministries fumanchu at amor.org

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