Menu Types

Menus may be classified by two major types - Retained and Temporary. Retained Menus are assigned an identifier (Menu ID) and have an existence for the duration of a particular program or until explicitly dropped. The contents of a menu must be built up prior to using it by describing the descriptive text on each item button. These buttons may be changed dynamically throughout the program, but the menu itself has a unique identity (via its ID). Retained Menus are particularly useful in a graphics environment utilising intelligent hardware, where the menu contents may be downloaded to the device, enabling very rapid refreshing of the screen and movement between menus. Temporary Menus have only a transient existence, all information associated with the menu (its title, descriptive text on each button, variables to be modified etc.) being totally defined by a subprogram call. Within the general classes of Retained and Temporary Menus, further subdivisions allow for the following Menu Types:-

Action Menu

Each Button on the Menu is associated with an Action Response Command Text String. Selection of a Button will result in this Command Text String being placed in the input buffer as if it had been typed in by the User. If an Action Routine has been declared for the Verb portion of the Text String, then it will be called automatically, otherwise the Verb itself will be returned to the Caller.

Select Menu

The Operator may select one Button on a menu, the number of the Button being returned to the caller.

Toggle Menu

Each Button on the Menu is associated with a Logical Variable that can either be set TRUE or FALSE. Selection of a Button will toggle it between these two states.

Integer Menu

Each Button on the Menu is associated with an Integer Variable. Selection of a Button will allow its current value to be modified. Upper and Lower bounds may optionally be applied to limit the range of allowed responses.

Real Menu

Each Button on the Menu is associated with a Real Variable. Selection of a Button will allow its current value to be modified. Upper and Lower bounds may optionally be applied to limit the range of allowed responses.

Mixed Menu

This is a combination Integer/Real/Logical Menu. Each Button on the Menu may be associated with an Integer, Real, Octal etc. variable. Selection of a Button will allow its current value to be modified.

Text Menu

Each Button on the Menu is associated with a Text String. Selection of a Button will allow its current value to be modified.