Navigating between frames

Navigation between frames comprises simple moves and command actions that change which frame is current. The following list describes all the ways to move between frames:

• The <PREV-FRM> and <NEXT-FRM> SLKs are assigned the prev-frm and next-frm FMLI commands, respectively. Pressing either of these SLKs will cause you to navigate from frame to frame. The frame navigated to becomes the current frame on the screen, and the frame navigated from becomes non-current. FMLI keeps a list of each frame that has been the current frame. For example, if frame N is current, pressing <PREV-FRM> will cause you to navigate to the frame that was current when frame N was opened. Pressing <NEXT-FRM> while in frame N will cause you to navigate to the last frame opened while frame N was current. Since the <PREV-FRM> and <NEXT-FRM> commands are always relative to the current frame, the order in which they cause navigation through the frames displayed in the work area does not always follow frame ID order, and wrapping occurs in the order described above.

• Selecting frm-mgmt from the Command Menu will bring up a choices menu that includes the item LIST. Selecting LIST brings up another choices menu listing all opened frames. When you select a listed frame, the choices menu disappears and the selected frame becomes current. If you do not want to select a listed frame, you can press the <CANCEL> SLK. The choices menu will disappear and you will be put back in the frame you started out in.

• You can enter a frame ID number on the command line and press <ENTER>. The frame with that ID number will become current. This is equivalent to executing the goto command on the command line with a frame ID number as an argument, or selecting goto from the COMMAND MENU, entering a frame ID number after the prompt on the command line, and pressing <ENTER>. For a discussion, see the next section.

• Opening (selecting) a frame will always cause navigation to that frame.

• Closing (canceling) a frame will cause navigation to the ``backup'' frame. The concept of a backup frame allows FMLI to maintain a linked list of frames so that users always have a frame to which they will automatically be returned when a frame is canceled. The logic behind what frame is backup frame for another is not always immediately apparent to users, but its purpose is to maintain a linked list in which every frame is the backup frame for only one other frame. Usually, the backup frame is the frame that was current when the frame being closed was opened. However, if a user has been doing rather convoluted navigation, a frame's backup frame can change dynamically. For example if frame A is current and frame B is opened, A becomes B's backup. If A was already C's backup, B becomes C's backup.

• The cleanup command will close all frames whose lifetime descriptor evaluates to shortterm or longterm. If the lifetime descriptor evaluates to immortal, it means the frame cannot be closed except by exiting from the FMLI application. Note that the lifetime descriptor for initial frames, that is, frames opened as arguments to fmli when it is invoked, evaluates to immortal by default and cannot be redefined.