Proposal: reducing self.x=x; self.y=y; self.z=z boilerplate code

[Ralf W. Grosse-Kunstleve]

--- Lonnie Princehouse <finite.automaton at gmail.com> wrote:

> IIRC, the self.__dict__.update(locals())  trick confuses psyco.
> 
> But you can make a decorator to achieve the same result.  There's not
> really a convincing case for extending python syntax.

Not if you have (enough memory for) psyco. :)
I am doing C++ extensions by hand; did quite a lot of them. Anything that helps
in pushing back the point where I have to move from Python to C++ is highly
appreciated. That's probably the strongest argument for the (self, self.x, ...)
approach. I believe it can be made more efficient than any other solution. But
see also the two other arguments:

    http://mail.python.org/pipermail/python-list/2005-July/289721.html

> def attribute_decorator(f):
>     import inspect
>     argnames = inspect.getargspec(f)[0]
>     def decorator(*args, **keywords):
>         bound_instance = args[0]
>         for name, value in zip(argnames[1:], args[1:]):
>             setattr(bound_instance, name, value)
>         return f(*args, **keywords)
>     return decorator
> 
> #--------- example use:
> 
> class foo(object):
>     @attribute_decorator
>     def __init__(self, thing):
>         print "init: self.thing is", repr(self.thing)
> 
> f = foo('hello world')

Thanks! Rob Williscroft had a similar suggestion:

    http://mail.python.org/pipermail/python-list/2005-July/289734.html

Does anyone know if there is a way to hide the _ or self_ from the user of the
class, i.e. given:

    class foo(object):
      @attribute_decorator
      def __init__(self, x, _y, z):
         pass

can we make it such that the user can still write

    foo(x=1,y=2,z=3)

without the underscore?

Cheers,
        Ralf


		
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