Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.python > #36855 > unrolled thread

Re: i can't understand decorator

Back to article view | Back to comp.lang.python

This discussion starts older than the indexed window; earlier articles aren't shown. The article labeled Started by below is the oldest one visible, not the original post.

Contents

  Re: i can't understand decorator Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-01-15 14:31 +0000

#36855 — Re: i can't understand decorator

On 15 January 2013 14:20, contro opinion <contropinion@gmail.com> wrote:
>>>> def deco(func):
> ...      def kdeco():
> ...          print("before myfunc() called.")
> ...          func()
> ...          print("  after myfunc() called.")
> ...      return kdeco
> ...
>>>> @deco
> ... def myfunc():
> ...      print(" myfunc() called.")
> ...
>>>> myfunc()
> before myfunc() called.
>  myfunc() called.
>   after myfunc() called.
>>>> deco(myfunc)()
> before myfunc() called.
> before myfunc() called.
>  myfunc() called.
>   after myfunc() called.
>   after myfunc() called.
> 1.
> why there are two lines :before myfunc() called.and tow lines :after
> myfunc() called. in the output?

You have wrapped the function twice with the decorator. Try changing the line
    print("before func() called")
to
    print("about to call", func,__name__)
and you'll see that the function it is about to call is not the same
in both cases.

> 2.why the result is not
> before myfunc() called.
>  myfunc() called.
>   after myfunc() called.
> before myfunc() called.
>  myfunc() called.
>   after myfunc() called.

You would get this output if you just called myfunc() twice. I don't
know why you expect wrapping the function twice to have this effect.


Oscar

[toc] | [standalone]

Back to top | Article view | comp.lang.python

csiph-web