Using record structure classes

Visual Programming User Guide : Using external functions : Accessing external functions : Accessing external functions from scripts : Using record structure classes

The generated PPtl record structure class includes five methods, as follows:

xAt: and xAt:put:

Get and set instance methods for the x value of each point in the array of points.

yAt: and yAt:put:

Get and set instance methods for the y value of each point in the array of points.

initializeAfterLoad

Class method that sets the fixed size of the record, not counting any variable components.

Instead of the techniques used in the defaultRows and setParameters scripts of the previous section, a script segment similar to the following can now be used to initialize an array of points:

| pointArray |

pointArray := PPtl new.

pointArray xAt: 1 put: 0;

yAt: 1 put: 0;

xAt: 2 put: 50;

yAt: 2 put: 50;

xAt: 3 put: 90;

yAt: 3 put: 25;

xAt: 4 put: 120;

yAt: 4 put: 125;

xAt: 5 put: 145;

yAt: 5 put: 110;

xAt: 6 put: 170;

yAt: 6 put: 120;

xAt: 7 put: 180;

yAt: 7 put: 105;

xAt: 8 put: 200;

yAt: 8 put: 130.

Now you are ready to access the drawGraph external C function and pass the pointArray you just created as a parameter.

Last modified date: 01/29/2015