[Pipet Devel] pygtools tutorial - some definitions

J.W. Bizzaro bizzaro at bc.edu
Tue Jun 1 21:41:45 EDT 1999

In case you are unfamiliar with some of the terminology of modern object
oriented programming (OOP), here are some plain English definitions and

"Class"        - This is how "objects" are classified.
               - Each object belongs to a class or category.
               - There is a hierarchical arrangement of objects
                 "methods" and other classes, under classes.

"Object"       - An object is a data structure that can "inherit"
                 the properties of its parents.
               - Objects fall under classes.

"Method"       - A method is a function or procedure, which means
                 it actually does something to something.
               - Methods also fall under classes.

"Instance"     - A unique copy of a "class" with all of its
                 methods and objects.
               - A change in one instance does not affect
                 other instances.

"Event"        - An event is when something happens in a GUI.
               - It can be a mouse movement, button click, etc.
               - Event handlers are "methods".

Here is a Python example:

MyClass:                             # A new class is defined.

    def my_method(self, my_number):  # A new method is defined
                                     # with the parameter "my_number".

        self.my_object = number      # A new object is defined.

my_intance = MyClass()               # An instance is made.
my_instance.my_method(2)             # The method is called.
print my_instance.my_object          # This will print "2".

(Let me know if something is wrong here.)

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