[Python-Dev] method decorators (PEP 318)

[Skip Montanaro]

    Barry> attributes, but decorators can also do the trick in a nasty way:
    Barry> 
    Barry> def foobar [
    Barry>     lambda f: f.author = 'Guido van Rossum',
    Barry>     lambda f: f.deprecated = True,
    Barry>     classmethod] (self, arg):
    Barry>     # Now what?

    Alex> Not necessarily all that nasty:

    Alex> def foobar [ with_attributes(
    Alex>          author="Guido van Rossum",
    Alex>          deprecated=True),
    Alex>      classmethod] (cls, args):
    Alex>          pass

Both cases demonstrate why I don't like the decorator-before-args option.
Where are the args?  Like I said in an earlier post most of the time I look
at a function def wanting a quick reminder how to call it.  If the argument
list doesn't at least start on the same line as the def I think that will be
tougher.

    Alex> with a built-in 'with_attributes' equivalent to:

    Alex> def with_attributes(f, **kwds):
    Alex>      for k, v in kwds.iteritems():
    Alex>          setattr(f, k, v)
    Alex>      return f

Not quite.  It has to be written as a function which returns another
function, e.g.:

    def attrs(**kwds):
        def decorate(f):
            f.__dict__.update(kwds)
            return f
        return decorate

Skip