The Generator Editor is an interactive development environment for creating, editing and managing generators. It allows you to view, edit and run available generators, and to create new generators for your needs. An example Generator Editor window is shown in Figure 5–10.

At the top of the Generator Editor window there is a menu bar and a toolbar. Below the toolbar are three list boxes, an editing area and a list of errors at the bottom. The Generator Box, the left list box, offers a list of generators. By default the generators for the currently selected Graph type are displayed, along with the hierarchy of subgenerators they call. You can also choose to display other non-hierarchical lists of generators from the menu box above the list. Other possible options are alphabetical order, ascending and descending chronological order, generators with breakpoints, generators that failed the syntax check and generators found by the last Advanced Find command.

The center list box is the Concept Box, where you can select what to view in the right list box: Graph, Object, Port, Role or Relationship types of the current modeling language, or templates for the MERL generator definition language. The templates contain the syntax elements and commands of the language, and have been categorized to make them more accessible. The category ‘Templates’ contains all templates, while sub-categories ‘General’, ‘Control’, ‘External I/O’, ‘Strings & Numbers’ and ‘Representations’ contain only templates for commands of that type.

The right list box, called the Choice Box, provides a list based on the choice in the Concept Box: either a tree of types and their properties, or a list of the templates in the category that has been selected in the Concept Box. Double-click any of the listed items to paste it into the Editing Area.

Under the list boxes is the main Editing Area, which shows the currently selected generator definition. The editing area supports the normal editing operations (cut, copy, paste, select, find, replace) and font formatting.

Below the editing area, there is the List of Errors at the bottom of the window. Any errors found in the current generator are reported here when you save the generator or check its syntax.