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PPG Application Design
18 PT Program Generator (PPG) v5.0
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
Opera-
tion Nodes
. Most developers start by creating Function Nodes.
Frames
Frames contain a set of program steps that are collected and ordered in a logi-
cal 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-con-
tained 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 func-
tion 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 pro-
gram 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 dif-
ferent types of
Operation Nodes to chose from, as shown in Table 1 on page 17.
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