What is the difference between Pre Points, Post Points and Edit Points in the action diagram? Which should be used to add action diagram code?
In early releases of Plex, Edit Points were the only places within an inherited action diagram where additional instructions could be added. Edit Points could be (and still can be) inherited through multiple levels of a function's Inheritance Path. If you added code into one of those Edit Points, then you could not use that same Edit Point to add additional code in a lower level function in the Inheritance Path. This was restrictive because only empty inherited Edit Points allowed additional code to be inserted.
In current releases of Plex, every Edit Point is now joined with a Pre Point and a Post Point of the same name. The Pre Points and Post Points are also referred to as "Collection Points" because they are designed to collect code from all the functions in the function's Inheritance Path. In other words, you can always add code to the bottom of a collection point in any action diagram, regardless of whether it has been used before.
Although it is still possible to add code into the Edit Points, we recommend that you avoid them and use the Collection Points instead. You will notice that most inherited code gets collected into the Pre Points of your action diagrams. You may always add code after the inherited code in a Pre Point, but you may want to use Post Points as a general rule to keep your code separate from the inherited code, unless your code logically belongs with the inherited code.
For more information, see the "Edit Points and Collection Points" section of the "Designing functions" chapter in the CA Plex User Guide in the online help.