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


Groups > comp.lang.python > #106244

Re: [Python-ideas] Decorators for variables

From Ian Kelly <ian.g.kelly@gmail.com>
Newsgroups comp.lang.python
Subject Re: [Python-ideas] Decorators for variables
Date 2016-04-01 11:25 -0600
Message-ID <mailman.321.1459531585.28225.python-list@python.org> (permalink)
References <CAEze2WgR7NdR9j01aAB9_hC_hx02nSu7fS2M8ain_P+JjRBcqw@mail.gmail.com>

Show all headers | View raw


On Fri, Apr 1, 2016 at 11:14 AM, Matthias welp <boekewurm@gmail.com> wrote:
>> An example of the transformation would help here
>
> An example, that detects cycles in a graph, and doesn't do an update if
> the graph has cycles.

Thanks.

> class A(object):
>     def __init__(self, parent):
>         @prevent_cycles
>         self.parent = parent

I think you'll find that this doesn't work. Properties are members of
the class, not of instances of the class.

> This would prevent cycles from being created in this object A, and would
> make
> some highly reusable code. The same can be done for @not_none, etc, to
> prevent
> some states which may be unwanted.

But you could accomplish the same thing with "self.parent =
prevent_cycles(parent)". So I'm still not seeing how the use of the
decorator syntax eliminates repetition.

Back to comp.lang.python | Previous | Next | Find similar | Unroll thread


Thread

Re: [Python-ideas] Decorators for variables Ian Kelly <ian.g.kelly@gmail.com> - 2016-04-01 11:25 -0600

csiph-web