[Python-Dev] Decorators: vertical bar syntax

[Guido van Rossum]

>    A motivation for this was that one of the examples
> 
> @accepts(int,int)
> @returns(float)
> def bar(low,high):
> 
>    which separates related information too much for me. If
> decorators need to decorate parameters, they are more likely to be
> understood correctly by a reader if the decorations are next to the
> parameters.

Let's make one thing clear; while decorators may be useful for some to
experiment with attaching signatures to methods, mainstream Python
will eventually have optional static typing built in, and it won't use
decorator syntax.  (More likely you would specify argument types by
saying e.g. "def bar(low: int, high: int) -> float: ...")

--Guido van Rossum (home page: http://www.python.org/~guido/)