Welcome to VisualWorks

% visualworks /usr/local/visual/image/visual.im

Two small windows will pop up: the main window and a workspace. The main window and the workspace window are shown below:



2. Writing some very simple expressions.
We will not be looking at all of the menu and button options in the main window, but right now you can use the workspace and practice writing some simple Smalltalk expressions.

Try typing:

• 3 + 4. To execute the expression, highlight it and then middle-mouse click. Select "print it" from the pop-up menu. Woo!
• Transcript show: 'Hello!'. Select "do it" from the menu this time to execute.
• Transcript show: 'Smalltalk is fun!'.
• etc...

To open a System Browser, select Browse->All Classes from the main window or use the shortcut button . Notice that a System Browser is divided into four columns across the top half of the window, and the bottom half contains a text area.

The first column is the Categories column; the classes are first organized by categories, to make it easier to manage them (and there are hundreds of them). These categories are completely arbitrary, so you can reorganize the classes any way you want. After you select a category, a list of the classes in that category will appear in the the second column, the Classes column. When you select a class, the members of the Protocols column appear; these are just groups of methods. Select a protocol and finally, the methods of the class will show in the last column, Methods.

Have fun exploring VisualWorks on your own, but the help system doesn't seem to work. Notice also, that when you quit VM it will prompt you to "save" something -- type in /home/your_name/me.im. Now, when you start VW again you just have to type visualworks me.im and all of your work from the last session has been saved!

"Hello, World"

In this section, you will learn how to make a new class using the System Browser.

1. Middle-click in the first column and select add from the pop-up menu to create a new category. Call it Test.
2. In the lower half of the browser, you will see a generic class definition. You will need to write in new information, so that the definition looks like this:

           Object subclass: #HelloWorld
               instanceVariableNames: ''
               classVariableNames: ''
               poolDictionaries: ''
               category: 'Test'
   

3. Middle-click in the coding area (where you just finished typing) and select accept. This compiles the definition and creates the new class HelloWorld.
4. Go to the third column and middle-click, selecting add to add a new protocol. You can name the protocol printing fun.
5. Now go to the coding area again and write in your method.

        print 
           ^'Hello, World'
   

6. Use accept to compile the method and we're done!
7. To run your program, go to the workspace and create an instance of the class HelloWorld.

           Hi := HelloWorld new. /* middle-click mouse and select "inspect" */
           Hi print. /* middle-click and select "print it" */
   

   After you inspect the first part, VisualWorks will prompt you to declare Hi as a global or temporary variable. Choose global, so that when you run the second statement, you will not have to highlight the first statement.

Factorial in Smalltalk

You are now ready to begin writing your first factorial program in Smalltalk. Go to the coding area in the lower half of the window and write:

recFact
self < 0
     ifTrue : [^0]
     ifFalse: [
         self = 0 
             ifTrue : [^1]
             ifFalse: [^self * (self -1) recFact]
              ]