PPG Application Design

Creating Function Nodes

Once you’ve designed the basic program structure, the next step in generating a portable program is to define each Function Node. Function Nodes are frames or subroutines and are used to organize the steps and work of Operation Nodes. Most developers start by creating Function Nodes.

Frames

Frames contain a set of program steps that are collected and ordered in a logical structure. Frames can consist of other frames, subroutines, and nodes. Nodes are Linked together within the frame using Links.

Subroutines

Subroutines contain nodes that execute program steps, much like Frames, but they can be called from anywhere in the application. They should be self-contained and perform functions that are used in multiple places in the applica- tion. Use Call nodes to link Subroutines to the location within the Operation Node or Frame where they will be called.

Using Your Flow Chart

Using the flow chart you created in Application Structure on page 16, list the Frames and Subroutines you will define. As a general guideline, if the function is used in multiple places, make it a Subroutine. Otherwise, it should be a Frame. Once all Function Nodes are created, define each step by creating the Operation Nodes.

Creating Operation Nodes

Each Operation Node represents a program step or work performed by the application. After you have created the frames and subroutines, fill in the program steps for each function node. Using the flow chart, create an appropriate Operation Node for each step in the Frame or Subroutine. There are nine different types of Operation Nodes to chose from, as shown in Table 1 on page 17.

18

PT Program Generator (PPG) v5.0