Topic       : The GFA-Basic Compendium
Author      : GFA Systemtechnik GmbH
Version     : GFABasic.HYP v2.98 (12/31/2023)
Subject     : Documentation/Programming
Nodes       : 899
Index Size  : 28056
HCP-Version : 3
Compiled on : Atari
@charset    : atarist
@lang       : 
@default    : Document not found
@help       : Help
@options    : +g -i -s +z
@width      : 75
@hostname   : STRNGSRV
@hostname   : CAB     
@hostname   : HIGHWIRE
@hostname   : THING   
View Ref-FileON MENU GOSUB
MENU, MENU OFF, MENU KILL

In this section the commands specific to GFA BASIC 3 for control of
pull-down-menus are given. Unfortunately a certain confusion prevails in the
literature on this topic as to the meaning of some of the terms used. They
shall therefore be stated here as they are used in this manual. We use the term
'pull-down-menu' as a general term for menu titles or headings. In the top
screen line the constantly visible part of the menu, is where the menu list is
located. This contains the individual headings. If the mouse arrow arrives at
one of these headings, then under it a so-called menu which unfolds.  Each part
of this menu can be selected individually as a menu entry. This choice of
terminology is not generally obligatory but is used throughout this manual,
elsewhere slightly different definitions are used.

During the creation of a menu its entries are set in an array m$(). With the
command MENU m$() this pull-down-menu is displayed on the screen. The command
ON MENU GOSUB determines which procedure the program branches to on the
selection of a menu entry. When the program is running, a check is made to see
whether an entry was selected on each occurrence of an ON MENU command.

The command MENU OFF returns reverse video entries in the menu list to normal
display. With MENU KILL the menu is switched off. The command MENU x,y enables
menu entries to be provided with checkmarks or to be displayed in light text,
making this menu entry non-selectable.

Memo: If the procedure used with ON MENU is undefined the compiler will
      not issue and error message. Instead the compiler writes a bad binary
      where ON MENU is translated into JSR 0.l!