User`s guide

Building a Menu Structure
The strategy for implementing a menu is:
1. Declare the top-level bar menu.
2. Start a loop monitoring event 14 (menu selection).
3. When event 14 is detected, check to see if the mouse event was on the top-level bar
menu or on a pull-down option.
4. If the event was a top-level menu selection, then display the proper pull-down options.
5. If the event was a pull-down selection, use nested CASE structures to take appropriate
action based on the selections made to the top-level menu and its corresponding pull-
down menu.
Menu Example
This code segment will implement a menu structure for a window open on glun:
; Set the top-level menu bar and enable monitoring of events
FSET (glun) "/menu 'Menu 1' 'Menu 2' 'Menu 3'"
FSET (glun) "/event button menu"
; Define the strings for the pull-down menus
$menu[1] = "'Item 1-1' 'Item 1-2'"
$menu[2] = "'Item 2-1' 'Item 2-2' 'Item 2-3'"
$menu[3] = "'Quit'"
; Set variable for event to be monitored
wn.e.menu = 14
; Start the processing loop
quit = FALSE
DO
GETEVENT (glun) event[]
IF event[0] == wn.e.menu THEN
;The menu event (14) has two components; a button-down component
; corresponding to a click on a menu bar selection, and a
; button-up component corresponding to the pull-down selection
; made when the button is released.
; After the first component (pointer down on the menu bar),
; event[1] will be 0 and event[2] will have the number of the
; menu bar selection.
; Check to see if event[1] is 0, indicating a top-level menu select
IF event[1] == 0 THEN
; Use the value in event[2] to select a pull-down menu
FSET (glun) "/pulldown", event[2], $menu[event[2]]
; Else, execute the appropriate code for each menu selection
ELSE
; If event[1] is not 0, then the button has been released on a
; pull-down selection and:
Building a Menu Structure
V+Language User's Guide, v17.0
Page 250