fcy@ihuxr.UUCP (Fred Yankowski) (01/06/84)
A recent article in *Software -- Practice and Experience*
describes an appealing scheme for providing a hierarchical
menu tree for user command selection. As earlier net.cog-eng
articles have pointed out, two major problems with command
menus are that:
1. It is easy to become "lost" in the menu tree.
2. It is often a difficult and slow process to maneuver
between remote parts or the menu tree.
The design presented (and implemented) by the authors
addresses both of these problems using two related
techniques.
1. The users current position in the tree is always
displayed (on a bit-mapped device in this case) as the
list of menu "nodes" from the root of the tree to the
current position. This list is presented as a stack,
with each menu selection adding an item to the bottom
of the downward-growing stack. The menu choices
available at the current node are displayed just below
the bottom of this stack.
2. The system remembers the last selection made from each
node and makes it the default when the node itself is
next selected. As a result, selecting one of the top
nodes in the tree may result in a default path all the
way to a "leaf" node.
The first problem mentioned above (location) is nicely
solved by the stack-like display of the current position
which reminds the user exactly how the current node was
reached and where alternate choices might have been made in
this path. Maneuvering within the tree is simple and quick
given the following method for choosing the next node.
Selection Downward movement in the tree is accomplished by
selecting one of the menu items available at the
current node (ordinary enough). However, the
defaults established at lower nodes may cause
the user's position to advance several steps
down into the tree. This is safe because it is
very easy to back up (described next) and menu
traversal does not cause any side effects until
the user commits to a leaf node via a separate
"trigger".
Rejection The user may "back up" in the menu tree by
canceling one of the values in the path stack
mentioned earlier. This "pops" the stack back
to the node above the cancelled node, providing
the menu that included the cancelled node.
Default paths are *not* taken from this new
node.
The resulting mechanism would seem to be very convenient and
natural as there are only two traversal operations:
selection and rejection.
The complete reference for the article is:
Publication: Software -- Practice and Experience
Authors: Apperley, M.D. and Spence, R.
Article title: Hierarchical Dialogue Structures in
Interactive Computer Systems
Volume: 13, 1983.
Pages: 777-790
Fred Yankowski
ihnp4!ihuxr!fcy
AT&T - Bell Laboratories
Naperville, Illinois