You can use a variable type called structures to place extensions on a variable to identify a sub-element of that variable. Consider this example:
ASSIGN/V1.HEIGHT=6
ASSIGN/V1.WIDTH=4.3
ASSIGN/V1.MODE="CIRCULAR"
ASSIGN/V1.POINT=MPOINT(100.3,37.5,63.1)
In this example:
V1 is the structure.
HEIGHT, WIDTH, MODE, and POINT are sub-elements of the structure.
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