def decorator(func): def wrapper(butts): print("I am a great decorated function that now needs an argument!", butts) func() print("And this is after the function call.") print("Decorating!") return wrapper print("Decorator defined.") @decorator def foo(): print("Bar") print("Function with decorator defined.") foo("I am the argument") print("Function with decorator called.") def __main__(): def decorator(func): def wrapper(butts): print("I am a great decorated function (within a function!) that now needs an argument!", butts) func() print("And this is after the function call (in a function call!)") print("Decorating!") return wrapper print("Decorator defined.") let i = 42 let l = [1,2,3] @decorator def foo(): print("Bar (the inner one)") print("Function with decorator defined.") foo("I am in the inner wrapper.") print("Function with decorator called.") print("I like the numbers", l) print("Calling main.") __main__() def methodDecorator(func): def wrappedMethod(instance, butts): print("I need an extra arg:", butts) func(instance) print("Done.") return wrappedMethod class Foo(): def __init__(self): self.foo = "bar" print("I am an initializer.") def undecorated(self): print("I am here.") print("self.foo =", self.foo) @methodDecorator def decorated(self): print("(decorated) self.foo = ", self.foo) let f = Foo() f.undecorated() print("Returned from f.undecorated()") f.decorated("butts") print("Returned from f.decorated()") def decoratorWithArgument(decoratorArg): def theActualDecorator(func): print("I am decorating",func.__qualname__,"with this argument:",decoratorArg) def wrapped(): print("This wrapper captured this decorator arg:", decoratorArg) func() return wrapped return theActualDecorator @decoratorWithArgument("foo") def decoratedWithArgument(): print("I don't take any args of mine own, and nor does my wrapper.") decoratedWithArgument() def methodDecoratorWithArguments(decoratorArgA, decoratorArgB): def theActualDecorator(method): print("I am decorating", method.__qualname__, "with these args:", decoratorArgA, decoratorArgB) def wrapped(instance, wrapperArg): print("I captured these from the decorator:", decoratorArgA, decoratorArgB) print("I also take my own argument:", wrapperArg) method(instance,"and modify this one") return wrapped return theActualDecorator class Bar(): def __init__(self): self.foo = "weee" @methodDecoratorWithArguments("foo","bar") def superDecoratedMethod(self, arg): print("I am method, so I can access myself", self.foo, "and also my own argument which is now", arg) let b = Bar() b.superDecoratedMethod("this arg goes to the wrapper") def genericDecorator(func): def wrapper(*args,**kwargs): print("I am a generic wrapper, I will pass all of my args along.") func(*args,**kwargs) print("And I am done.") return wrapper @genericDecorator def aMethod(with_,args=None): print("I got",with_,"and",args) try: aMethod() except: print(exception.arg) aMethod("just the first") aMethod("the first","and the second") aMethod(args="hello",with_="world") try: aMethod(foo="hello",with_="bar") except: print(exception.arg) # unrecognized keyword arg, from inner method aMethod(*[1,2]) try: aMethod(*[1,2,3]) except: print(exception.arg) # too many arguments