4GL event sections

A 4GL script can contain one or more of the following types of sections:

• Program sections
• Zoom.from sections
• Form sections
• Group sections
• Choice sections
• Field sections
• Main table sections

With the exception of program sections, each section consists of a main section and one or more subsections. A main section indicates the object for which the programmed actions must be executed. A subsection specifies when the actions must be executed. Program sections consist of a main section only.

If you do not include a main section immediately before a subsection, the subsection is assigned to the previous main section in the script. For example:

 choice.print.data:    | main section
 before.choice:        | subsection of print.data
    ...
    ...
 after.choice:         | subsection of print.data
    ...
    ...

The following rules apply to the ordering of sections within a script:

• The declaration section (a program sections) must be the first section in the script.
• The functions section (also a program section) must be the last section in the script.
• Other sections can occur in any order, but the preferred order is: program sections, zoom.from sections, form sections, group sections, choice sections, field sections, main table sections.
• Do not mix sections of different types. For example, do not define a choice section, followed by a field section, and then a choice section again.

Variables declared in the declaration section are global variables that you can use in all sections. Variables declared within any other section are local variables that you can use in that section only.

Related help topics

• 4GL programming features (overview)
• Flow of 4GL engine