lazy_prop.py

# Used as a property on field-like things meant to be computed once.
def lazy_property(func):
    name = func.__name__
    class SuicidalGetter(object):
        def __get__(self, instance, owner):
            # Replaces itself with the result of instance.func()
            setattr(instance, name, func(instance))
            return getattr(instance, name)  # Oh and return the result
    return SuicidalGetter()
    
    
    
# Example:

import time
    
class Test(object):
    @lazy_property
    def quick_maths(self):
        print("Actually ran this time!")
        time.sleep(3)
        return 2 + 2
        
t = Test()
t.quick_maths  # Prints and takes 3 seconds
t.quick_maths  # Same answer, takes no time

I believe in a very "pull yourself up by your bootstraps" approach, so I don't appreciate the title of this property. Can we rename to "cacheing_prop" so there's no negative connotation? I explicitly refuse to include the word "lazy" in my codebase. My developers aren't lazy. I'm not lazy. This is America. There is no place for lazy people