The issue of conditional decorators came up recently. It was brought up in reference to pytest on Twitter. The following's a quick snippet to make the point.
Basic Code
def do_nothing_decorator(func):
return func
def print_hi_decorator(func):
def wrapper(*args, **kwargs):
print("Hi!")
return func(*args, **kwargs)
return wrapper
num_check = 5
conditional_decorator = print_hi_decorator if num_check > 4 else do_nothing_decorator
@conditional_decorator
def my_function(x):
return x+2
Now this example doesn't do much, it merely prints "Hi!" when the function is called.
The main idea is that there's some sort of check, in this case num_check that either applies the decorator and, if not, applies a do_nothing_decorator.
Output
>>> my_function(3)
Hi!
5
>>> my_function(4)
Hi!
6
Changing the Parameters
If we run the following to fail the if portion, we can see the expected output below. Don't forget that the conditional_decorator needs to be run with my_function again to 'reinitialize'.
num_check = 3
conditional_decorator = print_hi_decorator if num_check > 4 else do_nothing_decorator
@conditional_decorator
def my_function(x):
return x+2
Output
>>> my_function(3)
5
>>> my_function(4)
6
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