[Python-Dev] Decorators: vertical bar syntax

[Bill Janssen]

> In the discussion on decorators months ago, solutions involving
> special syntax inside the block were ruled out early on.  Basically,
> you shouldn't have to peek inside the block to find out important
> external properties of the function.

Guido, could you expand on this principle a bit?  Just stated as it
is, it sounds as pointless (to my untutored mind, at least :-), as the
arguments about "@ is ugly, so it shouldn't be used".  After all,
isn't "what the function does" an important external property of the
function, and don't you have to peek inside the block to determine
that?  For instance, how do you know whether a function is a generator
unless you look for yield statements inside it?

Bill