Why won't this decorator work?
MRAB
python at mrabarnett.plus.com
Sat Jul 2 13:33:33 EDT 2011
On 02/07/2011 17:56, John Salerno wrote:
> I thought I had finally grasped decorators, but the error I'm getting
> ('str' type is not callable) is confusing me. Here is my code. Also,
> the commented sentence is from the Python docs, which says it doesn't
> even need to be callable, if that matters. I also commented out a few
> things in the move method. They were just to see if it would work, but
> those lines raised even more errors!
>
> import random
>
> #space = 0
>
> def move(roll):
> # global space
> # space += roll
> return 'You moved to space {0}.'.format(roll)
>
> @move
> def roll_die():
> return random.randint(1, 6)
>
> # The return value of the decorator need not be callable
> # roll_die = move(roll_die)
>
>
>
> I tried running the command "roll_die()" and I get the error message.
>
> Thanks.
A decorator should return a callable.
This:
@move
def roll_die():
return random.randint(1, 6)
is equivalent to this:
def roll_die():
return random.randint(1, 6)
roll_die = move(roll_die)
You should be defining a function (a callable) and then passing it to a
decorator which returns a callable.
As it is, you're defining a function and then passing it to a decorator
which is returning a string. Strings aren't callable.
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