Notes from Dan Ingalls

Dan Ingalls notes

Smalltalk has
    Class - defines behaviors of instances
    Object - an instance of some class
    Selector - Name of a message
    Message - selector with parameters
    Method - code / procedure found in class for responding to a message


It is not essential to have classes, we can do OOP with just objects


Static types are not a requirement for OOP. Smalltalk usually follows dynamic types, but one version of smalltalk did have static types. That turned out to be not so useful.

Inheritance is not a requirement for polymorphism.

Smalltalk code initially ran 50 to 100 times slower than procedural code. Now it runs 5 to 10 times slower. (circa 1991)
Smalltalk mostly gets slowed down by the persistence requirement

OO code runs much slower than machine code.