Having an instance of a class take on a value?

What I mean by this is I'd like to implement behavior similar to that of the datetime class.

When you create an instance of datetime, the resulting object shows up as:

foo = 
  datetime
   24-Aug-2019 16:30:23
   
   

foo still maintains the fields:

'Format'
'TimeZone'
'Year'
'Month'
'Day'
'Hour'
'Minute'
'Second'
'SystemTimeZone'

But foo itself appears to have a "value" (which shows the day-month-year hour minute seconds values). This behavior is nice since it lets you do things like "foo1 - foo2" where both foo1 and foo2 are datetime objects and the resulting value is also a datetime.

I'm unsure of how to get this same behavior with a custom class of my own creation? I'm trying to implement my own time keeping class for astronomical purposes, so this kind of behavior would be extremely useful. I had originally attempted to use datetime as a superclass, however datetime appears to be sealed and so I cannot inherit from it unfortunately.

Any help would be greatly appreciated!

Answer 1

[Steven Lord]

You can customize how your object is displayed and overload operators and functions for your class.

[Chris Gnam]

Perfect! Thank you, overloading the operators was just what I was looking for. I just didn't know how to do that. Thanks so much!