On Sun, Aug 15, 2004 at 08:46:03PM +0100, Mark Russell wrote:
Here's my current attempt at describing the semantics in the reference manual:
A function definition may be wrapped by one or more decorator expressions. Decorator expressions are evaluated when the function is defined, in the scope that contains the function definition. The result must be a callable, which is invoked with the function object as the only argument. The returned value is bound to the function name instead of the function object. Multiple decorators are applied in nested fashion. For example, the following code:
@f1(arg) @f2 def func(): pass
is equivalent to:
def func(): pass func = f1(arg)(f2(func))
Is func actually defined when f1 and f2 are called? Looking at the code the VAR_STORE doesn't happen until after the decorators are added. [but I'm no expert on bytecode]. This won't matter for sane decorators but we're talking about the strange cases already. Reading the @ code top to bottom you would not expect func to be defined, but if you want it to be strictly like the 'func = decorate(func)' translation is should be. My patch to add support for class decorators defines func before the decorators as a side effect of moving Mark's decorator code out of com_funcdef (and yes, that was a plug). -Jack