Mike saves the day once again :-)) Thanks for the pointers, Im almost
there. Actually, I have to return a result and call the decorated
function:
def dec(func):
def newfunc():
print "About to call decorated function %s." % func.func_name
rslt = func()
print "Finished calling decorated function %s, result = %r." %
(func.func_name, rslt)
func() ## hier lies the problem because it actually needs
"self"
return rslt
return newfunc
How can I pass self to "func" ?
thanks!
On Jun 17, 10:53 am, "Mike Orr" <[EMAIL PROTECTED]> wrote:
> On 6/17/07, voltron <[EMAIL PROTECTED]> wrote:
>
>
>
>
>
> > I´m no decorator guru myself, but i dont think that decorators have to
> > return functions necessarily. But I had also tried what you suggested,
> > that gives me an exception:
>
> > exceptions.TypeError: 'NoneType' object is not callable
>
> > On Jun 17, 10:05 am, Christoph Haas <[EMAIL PROTECTED]> wrote:
> > > On Sun, Jun 17, 2007 at 12:47:47AM -0700, voltron wrote:
> > > > I am having problems using decorators with controllers. In a test
> > > > controller:
>
> > > > # testcontroller.py
>
> > > > def dec(func):
> > > > # do lotsa things
> > > > print "im doing something"
> > > > finished = True
> > > > if finished:
> > > > func() # call the function you were decorating
>
> > > > class HomeController(BaseController):
> > > > def index(self):
> > > > return render_response('index.html')
>
> > > > @dec(home)
> > > > def test(self):
> > > > return render_response('test.html')
>
> > > > tryinf this, I get an error:
> > > > exceptions.TypeError: home() takes exactly 1 argument (0 given)
>
> > > > I have to pass "self" to the function passed to the decorator somehow,
> > > > what would be the best way to do this? I want the decorator to carry
> > > > out a few things before calling the controller function its
> > > > decorating.
>
> > > I'm no decoration guru. But don't you have to "return func" in the
> > > decorator?
>
> Decorators are tricky enough themselves, but decorators with arguments
> are even more tricky. I haven't tried to write one but from what I
> understand, the main job of a decorator is to define a *local*
> function which calls the wrapped function, and then return the local
> function. So you have to replace your decorator with:
>
> def dec(func):
> def newfunc():
> print "About to call decorated function %s." % func.func_name
> rslt = func()
> print "Finished calling decorated function %s, result = %r." %
> (func.func_name, rslt)
> return rslt
> return newfunc
>
> @dec
> def test(...): ...
>
> I don't understand what you're intending to do with 'home' and
> 'finished', so I can't put them in my example.
>
> If you put arguments in the @ line, it's a decorator factory; i.e., it
> *returns* a decorator rather than "being" a decorator. Typically this
> means an additional level of local def, something like this:
>
> def factory(context):
> def dec(func):
> print "I am doing something wonderful with %r." % context
> def newfunc():
> print "About to call decorated function."
> print "I could do something with 'context'."
> print "Maybe I can even pass 'context' to 'func'?"
> rslt = func()
> print "Finished calling decorated function."
> return rslt
>
> @dec(home)
> def test(...): ...
>
> The two cases are consistent if you realize that the part following @
> is an expression: whatever it evaluates to is the decorator. A
> function with arguments is a function call: the return value is the
> decorator. A function without () is a function reference: the
> function itself is the decorator.
>
> The definitive spec for decorators ishttp://python.org/dev/peps/pep-0318/.
> The Nose package has several
> decorators with arguments n the 'nose.tools' module. They're pretty
> straightforward so they'd be good to study.
>
> --
> Mike Orr <[EMAIL PROTECTED]>
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