Sometimes you wish to re-use the elements of an existing type, but you need them at a specific location.
Using the inclusion mechanism, you can specify where will the element be included.
In our case, creating
Point3D would be as done as:
TYPE Point3D Point2D z AS SINGLE END TYPE
In this case,
y will be placed before
z in the UDT memory.
Should you need to have them after
z, just put the included type in different place:
TYPE Point3D z AS SINGLE Point2D END TYPE
z goes first, and