Example class Pizza(object): def __init__(self): self.toppings = [] def __call__(self, topping): # When using '@instance_of_pizza' before a function definition # the... Read More
Disclaimer: It seems that several people are concerned about presenting this solution, so I will provide a very clear disclaimer. You should not use this solution. I only provide it as information, s... Read More
Yes. Instead of passing in the instance attribute at class definition time, check it at runtime: def check_authorization(f): def wrapper(*args): print args[0].url return f(*args)... Read More
Other examples would be validation/filtering of the set attributes (forcing them to be in bounds or acceptable) and lazy evaluation of complex or rapidly changing terms. Complex calculation hidden be... Read More
If the goal is to have the same sort of effect in your code that #ifdef WINDOWS / #endif has.. here's a way to do it (I'm on a mac btw). Simple Case, No Chaining >>> def _ifdef_decorator_impl(plat,... Read More
You can't. Scoped names (closures) are determined at compile time, you cannot add more at runtime. The best you can hope to achieve is to add global names, using the function's own global namespace:... Read More
Maybe a bit of example code will help: Notice the difference in the call signatures of foo, class_foo and static_foo: class A(object): def foo(self, x): print "executing foo(%s, %s)" % (s... Read More
Since you are calling the decorator like a function, it needs to return another function which is the actual decorator: def my_decorator(param): def actual_decorator(func): print("Decorat... Read More
Decorators wrap the function they are decorating. So make_bold decorated the result of the make_italic decorator, which decorated the hello function. The @decorator syntax is really just syntactic su... Read More
If you are not into long explanations, see Paolo Bergantino’s answer. Decorator Basics Python’s functions are objects To understand decorators, you must first understand that functions are objects in... Read More