Classes

1. Defining a class with a method but no constructor, P has “self”

2. Creating instance of class does NOT require new in either

3. Class variables access in P via self or class name

4. P can assign instance attributes whenever it wants (within __ limitations), change types whenever, no concept of public/private

5. Constructors

6. Binding of constructor arguments to instance attributes (assignment, usage)

   ? - What happens if I don’t do var in the constructor? It’s unresolved later, but where does it go?

In fact, Kotlin has a rich, multi-layered approach to construction. Our class attribute greeting is marked as immutable (and should be marked with the optional private) as well.

In some ways, Python is clunkier in this example. We have the magic of “dunder” names on important methods, such as the “constructor”. The symbol of self is sprinkled in to give the instance scope a placeholder. And quite obviously, Kotlin’s primary constructor – right after the class name – is terse and doesn’t require assigning each value to “self”.

Note

Python’s __init__ is called a constructor, but as its name implies, it is actually an initializer. The __new__ method is the factory.

8. Kotlin does some magic behind-the-scenes creation of Java classes named from the file name, because Java needs classes