Create a new decorator

[survuvi]

What's not working?

# create my hello decorator
fn my_hello_decorator(func):
    fn wrapper():
        print("Hello,")
        func()
        print("Bye Bye!")
    return wrapper

# use my hello decorator
@my_hello_decorator
fn print_name():
    print("my name is Mark")

print_name()

The output should be:
Hello,
my name is Mark
Bye Bye!

Debug:
_error: Expression [5]:5:23: 'fn' parameter type must be specified
fn my_hello_decorator(func):

error: Expression [5]:10:12: 'fn() capturing -> None' value cannot be converted to 'None' in return value
return wrapper_

[DayDun]

The error message is solved by giving the function correct types:

fn my_hello_decorator(func: fn() -> None) -> fn() capturing -> None:
    fn wrapper():
        print("Hello,")
        func()
        print("Bye Bye!")
    return wrapper

@my_hello_decorator
fn print_name():
    print("my name is Mark")

print_name()

mojo does not yet support custom decorators though, so it will just print

my name is Mark

[survuvi]

Thank you

[iamtimdavis]

Thanks @DayDun for this answer! 🔥