Figure 5 is actually a screen dump of Altaira's rule editor. Each of the buttons in the editor is linked to a pulldown menu, from which the user is able to select any of the valid inputs or outputs. There are two ways to invoke the rule editor. First, for ruleset development, a menu option available from the execution engine's menubar invokes the editor with all inputs as 'dontcares'. Second, for debugging, if the user selects any of the rule outputs shown in the execution engine window, the rule editor is invoked with the rule that caused that output. In either case, the user is then free to navigate the ruleset by changing inputs, or to modify a rule by changing its outputs.
The state button menus in the rule editor have 'Edit' and 'New' selection buttons, in addition to selection buttons for all of the states which have been defined. If the user selects these buttons, a simple image editor, shown in Figure 7, is invoked to either create a new state or edit an existing state. The editor displays a 32 X 32 grid, which the user is able to use to draw an image by selecting colors from a palette and filling in pixels. The user is also able to use this editor to establish a tile state as terminal or non-terminal, and to declare the number of rotations it requires.
Another debugging mechanism available to the user is a rule
recorder, accessed from the execution engine. By pressing the
BCK and FWD buttons in the execution engine's control
area, the user is able to replay previous rule executions.