NET/MASTER Network Control Language (NCL) Programmer's Guide

Panel Skipping and Navigation in the Panel Hierarchy
Working With Panels
14–80 106160 Tandem Computers Incorporated
NCL supports navigation at two different levels. The default implementation handles
most navigation functions as part of the PANEL verb. However, you can explicitly
handle navigation in your NCL procedures if you wish.
Primary Menus and General
Menus
NonStop NET/MASTER MS supports two types of menus: primary menus and
general menus.
A primary menu is denoted by the display of a user ID and time on the right side of
the screen. NonStop NET/MASTER MS, therefore, has more than one primary menu:
the main, top-level, NonStop NET/MASTER MS primary menu, which appears when
you log on to NonStop NET/MASTER MS; the User ID Management Services (UMS)
primary menu; the System Support Services primary menu; and so on.
Conceptually, this means that a primary menu may appear under another primary
menu: for example, the UMS primary menu appears under the main, top-level
primary menu.
A general menu is any menu other than a primary menu.
Panel Skipping and the
END and RETURN
Functions
The END and RETURN function keys allow you to navigate through NonStop
NET/MASTER MS menus. The END function exits to the next higher-level menu in
the hierarchy. The RETURN function returns to the innermost primary menu (which
may not be the top-level primary menu). This means, in some cases, that the END and
RETURN functions appear to be the same. This is so when you use the END function
to exit from a menu one level below a primary menu.
Note The Operator Control Services (OCS) screen is a special case: it is regarded as a primary menu. Exiting
from a help panel is a special case: both the END and RETURN functions exit to the panel that invoked
the help panel.
Default Handling of END and RETURN
By default, the PANEL verb takes the following actions when it detects that the END
or RETURN function key has been pressed:
If the END function key has been pressed, the PANEL verb raises a PANEL_END
error. (The END function key is the F3 and F16 function keys on a Tandem 6530 or
compatible terminal, and the PF03 and PF15 function keys on an IBM 3270 or
compatible terminal.)
If the RETURN function key has been pressed, the PANEL verb raises a
PANEL_RETURN error. (The RETURN function key is the F4 and SF16 function
keys on a Tandem 6530 or compatible terminal, and the PF04 and PF16 function
keys on an IBM 3270 or compatible terminal.)
Your NCL procedures must trap both errors. The PANEL_RETURN error is typically
handled only for a primary menu. By contrast, the PANEL_END error is usually
handled for each general menu.