- An object is a data structure whose class can be determined
by the system. Objects are also called instances of a class.
- Conceptually, a class is a set of similar objects.
The classes we will use include integer, symbol,
null, pair, mobile, box, triangle.
A class defines a set of methods that can be used on members of the class.
The class of an object can be found using (class object).
In DrScheme, use drclass.
- A method is a procedure that performs some operation on
a member of a class. A method is specialized to the implementation of
- A message is an indirect procedure call. A message is sent
using the function send:
In DrScheme, use drsend.
(send object 'selector arguments)
- A selector is the generic name of a method, i.e., each class
to which the message might be sent will define a method corresponding
to the selector.
A selector can be thought of as an abstract procedure name.