Python Decorators

Transcript

1. Decorators What are they? How to explain them. Tuesday, June

   19, 12

2. Tuesday, June 19, 12

3. Basic definition Decorator is a function that takes a function

   as a parameter and returns a function Tuesday, June 19, 12

4. Basic definition Decorator is a function that takes a function

   as a parameter and returns a function Is a function. Takes a function. Returns a function Tuesday, June 19, 12

5. func = func_hugger(func) Illustration Tuesday, June 19, 12

6. def in_bed(func): def f(): return ‘%s In bed.’ % func()

   return f Change output Tuesday, June 19, 12

7. def in_bed(func): def f(): if f.in_pool: return ‘%s In pool.’

   % func() return ‘%s In bed.’ % func() f.in_pool = False return f Add attributes Tuesday, June 19, 12

8. def in_bed(func): def f(*args, **kwargs): if args or kwargs: raise

   Exception(‘wat?’) return ‘%s In bed.’ % func() return f Validate Tuesday, June 19, 12

9. Tuesday, June 19, 12

10. Basic definition Is a function. Takes a function. Returns a

    function Tuesday, June 19, 12

11. Syntactic Sugar Annotation Syntax Tuesday, June 19, 12

12. Syntactic Sugar Annotation Syntax @func Tuesday, June 19, 12

13. def luke_quote(): return “I’m Luke SkyWalker, I’m here to rescue

    you.” Decorate Tuesday, June 19, 12

14. def luke_quote(): return “I’m Luke SkyWalker, I’m here to rescue

    you.” Decorate @in_bed Tuesday, June 19, 12

15. def luke_quote(): return “I’m Luke SkyWalker, I’m here to rescue

    you.” Decorate @in_bed @no_inbreeding Tuesday, June 19, 12

16. def luke_quote(): return “I’m Luke SkyWalker, I’m here to rescue

    you.” Decorate @in_bed(with=”lightsaber”) @in_bed Tuesday, June 19, 12

17. Tuesday, June 19, 12

18. @eloy Tuesday, June 19, 12