The screen flow logic is the procedural part of a screen. It is created using an ABAP-like programming language on the flow logic tab page in the Screen Painter. The syntax rules of the screen flow logic are largely similar to the rules for ABAP. In particular, statements are ended using a period, chained statements can be formed, and the same rules apply for comments.
The screen flow logic, as an ABAP program, is structured from processing blocks. Possible processing blocks are the four event blocks for the screen events PBO, PAI, POH, and POV, which all start with the key word PROCESS. These event blocks contain a small set of statements that are described in the following sections, and which offer the the following functions:
The statements in the event blocks of the screen flow logic are normally processed sequentially. Branches result from error handling following input checks in dialog modules. Screen elements in table form are processed in loops.