On Tue, Apr 26, 2011 at 10:10 AM, Christophe Schlick <cschlick@gmail.com> wrote: <snip>
Part 2 - The new-style syntax for decorators:
Here is the code of the same decorators as in Part 1 above, but the proposed syntax. The first decorator ('new_style_repeat_fix') is created without parameters, while the second one ('new_style_repeat_var') uses arguments 'n' and 'trace' with the same role as previously:
#--- @decorator def new_style_repeat_fix(self, *args, **keys): """docstring for decorating function""" print "apply %r on %r" % (self.deco.__name__, self.func.__name__) for n in range(3): self.func(*args, **keys)
@decorator(n=3, trace=True) def new_style_repeat_var(self, *args, **keys): """docstring for decorating function""" if self.trace: print "apply %r on %r" % (self.deco.__name__, self.func.__name__) for n in range(self.n): self.func(*args, **keys)
I'm personally not a fan of magic such as having both @decorator and @decorator(...) work.
When examining the new-style syntax, one can notice that there are basically four characteristics that distinguish NSD from OSD:
* Each NSD is decorated by a newly-introduced callable class called 'decorator' (code provided in Part 3) by using one of two possible decorating forms. The first form '@decorator' is employed for decorators that do not need any parameter. The second form '@decorator(arg1=val1, arg2=val2...)' is employed to specify a sequence of named arguments (combined with their default values) that are passed to the decorator using the standard notation for keyword arguments.
What if my decorator's parameters don't all have default values? What if I don't want people to have to use keyword arguments when using my decorator? What if my decorator accepts extra positional arguments (i.e. *args)? Cheers, Chris