The Model Language

Arcs

Arcs in TML must be declared within a state declaration. The enclosing state becomes the arc's source. Arc definitions consist of two parts: the arc's stimulus, and the arc's destination.

Stimulus names in TML are enclosed in double quotation marks ".." and may consist of any printable characters other than the end of line and double quotation marks. Whitespace (except the newline) may be used in stimulus names. All stimulus names used for arcs within a single state declaration must be unique.

In its simplest form, the destination of an arc is just another state. This can be any state in the model, including the source state and the special states [Enter] and [Exit].

The following is an example model graph, and the corresponding model in TML.

model BigModelByStacy
  [Enter]
    "Begin"        [No Work]

  [No Work]
    "New"          [Work Unsaved]
    "Open"         [Work Saved]
    "Exit"         [Exit]

  [Work Saved]
    "Save"         [Work Saved]
    "Close"        [No Work]
    "Exit"         [Exit]

  [Work Unsaved]
    "Save"         [Work Saved]
    "Close"        [Confirm Close]
    "Exit"         [Confirm Exit]

  [Confirm Close]
    "OK"           [No Work]
    "Cancel"       [Work Unsaved]

  [Confirm Exit]
    "OK"           [Exit]
    "Cancel"       [Work Unsaved]
end

Figure 1: A simple model

The other possible destination for an arc is another model, called an included model. This topic is fairly complicated, and is discussed in the next section.