Project

Muppet Classes

Overview of project

• Author: Noel Rappin
• Indices on this project:
  • Example Of-OOP
  • Design Issue-Gen-Spec
• Complexity of this project: Low
• What you will have when you're done: Three classes that greet the user in different ways. By the end of this lab you should:
  • Understand the functions of the most common Smalltalk VisualWorks windows
  • Be able to create categories and classes in the System Browser
  • Be able to create protocols and write code for methods in the System Browser
  • Be able to use the Workspace to test your code.
• Strategy for this problem: Students create three classes -- a Muppet class that later serves as an abstract class, and two subclasses that serve as specializations of muppets.

  In this lab, we will use Smalltalk to create a small hierarchy of objects that are person (or muppet) like in that they have names and can greet you. You will create one abstract class called Muppet and two concrete classes called FrogMuppet and GrouchMuppet.

Steps in this project

• Start up Smalltalk and set up the Sources
• Create the 'Muppet' class.
• Create the FrogMuppet and GrouchMuppet classes.
• Create the methods for accessing and setting the name variable, initializing the greeting, and greeting.
• Initialize greeting to 'Hi Ho' for FrogMuppet, and initialize greeting to 'Go Away' for GrouchMuppet.
• Test the FrogMuppet and GrouchMuppet classes.
• Try out the inspector and debugger.

Representations of this project

• Steps in the procedure
• Class structure of Muppet Classes

Concepts used in this project

• More on the Transcript
• More on the System Workspace
• More on the System Browser
• More on what you use the Middle Mouse Button for - context-sensitive menus
• More on what you use the Left Mouse Button for - selections
• More on what you use the Right Mouse Button for - window management
• What is an abstract class?
• What is a subclass?
• What is a superclass?
• What is a generalization-specialization (gen-spec) relationship?
• What does a comma do in Smalltalk?
• What is the semicolon for in Smalltalk?
• About the Smalltalk Debugger
• About the inspector

Generics appearing in this project

• Create a class.
• Use the inspector

• Create a class.
• Use the inspector