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Re: Why won't this decorator work?

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From Ian Kelly <ian.g.kelly@gmail.com>
Date Sat, 2 Jul 2011 12:49:15 -0600
Subject Re: Why won't this decorator work?
To John Salerno <johnjsal@gmail.com>
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On Sat, Jul 2, 2011 at 12:08 PM, John Salerno <johnjsal@gmail.com> wrote:
> But why does the documentation say "The return value of the decorator
> need not be callable"?

Because the language does not enforce the restriction that the return
value should be a callable.  If it's not a callable, then the result
will just be that something non-callable is bound to the "roll_die"
name -- which could be useful, but is probably a bad idea in general.

> And why, if I remove the decorator and just
> leave the two functions as if, does the call to move(roll_die()) work?
> Isn't that what the decorator syntax is essentially doing?

No.  The decorator syntax is doing:

roll_die = move(roll_die)

If you then call roll_die, that is equivalent to "move(roll_die)()",
which is not the same thing as "move(roll_die())".

Cheers,
Ian

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Thread

Why won't this decorator work? John Salerno <johnjsal@gmail.com> - 2011-07-02 09:56 -0700
  Re: Why won't this decorator work? MRAB <python@mrabarnett.plus.com> - 2011-07-02 18:33 +0100
    Re: Why won't this decorator work? John Salerno <johnjsal@gmail.com> - 2011-07-02 11:08 -0700
      Re: Why won't this decorator work? Tim Chase <python.list@tim.thechases.com> - 2011-07-02 13:45 -0500
        Re: Why won't this decorator work? John Salerno <johnjsal@gmail.com> - 2011-07-02 13:39 -0700
          Re: Why won't this decorator work? Ben Finney <ben+python@benfinney.id.au> - 2011-07-03 08:36 +1000
          Re: Why won't this decorator work? "OKB (not okblacke)" <brenNOSPAMbarn@NObrenSPAMbarn.net> - 2011-07-03 18:01 +0000
            Re: Why won't this decorator work? John Salerno <johnjsal@gmail.com> - 2011-07-03 20:24 -0700
            Re: Why won't this decorator work? Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2011-07-04 20:22 +1200
      Re: Why won't this decorator work? Ian Kelly <ian.g.kelly@gmail.com> - 2011-07-02 12:49 -0600
        Re: Why won't this decorator work? Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2011-07-03 16:14 +1200
      Re: Why won't this decorator work? ChasBrown <cbrown@cbrownsystems.com> - 2011-07-02 12:16 -0700
      Re: Why won't this decorator work? ChasBrown <cbrown@cbrownsystems.com> - 2011-07-02 12:17 -0700
      Re: Why won't this decorator work? ChasBrown <cbrown@cbrownsystems.com> - 2011-07-02 12:16 -0700
      Re: Why won't this decorator work? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-07-03 12:11 +1000
        Re: Why won't this decorator work? John Salerno <johnjsal@gmail.com> - 2011-07-02 19:14 -0700

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