[Python-Dev] Re: method decorators (PEP 318)

[Samuele Pedroni]

At 10:15 28.03.2004 -0500, Bob Ippolito wrote:
>On Mar 28, 2004, at 9:45 AM, Phillip J. Eby wrote:
>
>>At 12:54 PM 3/28/04 +0100, Paul Moore wrote:
>>>Robert Mollitor <mollitor at earthlink.net> writes:
>>>
>>> > It would be nice if transformer decorations were never allowed
>>> > "arguments".  It would keep that list as short
>>> > and as tidy as possible.
>>>
>>>That's the sort of restriction I imagined that Guido was tending
>>>towards. While it's justifiable in this context, I would prefer to
>>>leave the option of using arguments available, in case someone comes
>>>up with a use where function attributes are inappropriate.
>>
>>It's inappropriate to use attributes of a function for attributes that 
>>logically belong to the decorator.  For example
>>'synchronized(lockattr="baz")'.  The 'lockattr' logically belongs to the 
>>synchronizing decoration.  Declaring it in a separate location makes the 
>>whole thing harder to read/understand.
>
>Not to mention the fact that you'll have to start prefixing your function 
>attributes so that you don't clash between decorators.. because of the 
>flat namespace.

yes, in fact C# and Java use first class objects, namely in their case 
classes/interfaces to solve the naming problem.

A comparable approach in Python would be:

author = object() # may be imported from somewhere else

def foo(arg):
   @author: "fooauthor" # === foo.__dict__[author] = "fooauthor"

so @ syntax would be "@expr : expr" and not "@name : expr".