Macro that compares two dates and returns time that has passed

Hey lovely people of GRAV,

I want to create a macro that compares two dates (now and when post was published) and returns the time that has passed since then !

Does someone have an idea ?

The built-in |nicetime filter already does this for you although it returns the difference in a human readable style. If this is not what you want there are plenty of examples of this on google: