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From: Mark H Harris <harrismh777@gmail.com>
Newsgroups: comp.lang.python
Subject: Simple Function Decorator Sample Snippet
Date: Mon, 12 May 2014 23:41:18 -0500
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Xref: csiph.com comp.lang.python:71424

hi folks, I've come up with a simple snippet that intends to explain the 
concept of decorations without an article (for on app help), while being 
succinct and concise, while not being overly complicated.

Does this work?   I have another one coming for args, similar, if this 
works...  comments appreciated.  thanks.

> # BEGIN FUNCTION DECORATOR SIMPLE ################################
> #
> # define the function decorator (wrapper function)
> def enter_exit(f):
> 	def new_f():
> 		print("entering", f.__name__)
> 		f()
> 		print(f.__name__, "exited !", end="\n\n")
> 	return new_f
>
> # the above "function decoration" takes a 'callable' as an argument
> #    and returns a 'callable' new function that is used to
> #    replace the original function (function is decorated),  which
> #    adds functionality to the original function being decorated ...
>
> # define the original function
> def f1():
>         print("    inside f1()")
>
> # replace the original function (above) with the new decorated
> #    'wrapped' function using the function decoration 'enter_exit'...
> f1 = enter_exit(f1)
>
> # (OR) accomplish the same thing with decoration lines as below:
>
> # functions wrapped with decoration lines syntax (annotations)
> #    as below, accomplish the same 'decoration' as above
> #    by using some 'syntactic sugar' to accomplish same ...
>
> @enter_exit
> def f2():
> 	print("    inside f2()")
>
> @enter_exit
> def f3():
> 	print("    inside f3()")
>
> # demo the new 'decorated' functions
> f1()
> f2()
> f3()
>
> # END FUNCTION DECORATOR SIMPLE ##################################