Tallis Composer is a tool for creating and editing PROforma applications, or “process-descriptions”: descriptions in the PROforma language of the tasks that are to be carried out by interacting agents, whether human beings or software components, in order to accomplish some objective.

Development of a process-description in Tallis Composer is a two step process:

1. Using the set of PROforma task types (plans, actions, enquiries and decisions), the high level structure of the process is laid out and assembled as a network.

The Tallis Composer screen capture above shows a network of tasks making up part of a (simplified) guideline for cancer diagnosis and treatment. The work flows in the direction of the arrows, from left to right. It begins with an enquiry about the patient's problem (green diamond), which in this example is unexplained weight loss. The enquiry is followed by a diagnosis decision (pink circle). In this case the diagnosis decision is a choice among a number of diseases that might be the cause of the weight loss. If cancer is diagnosed the workflow continues with a second decision: whether to treat the cancer with chemotherapy or surgery. Depending on the decision taken, the guideline is completed by enacting the appropriate treatment plan (red rounded rectangle).

Process-descriptions are displayed in Tallis both in a network view and in a tree view:

• The tree view displays the process-description’s hierarchical structure
• The network view displays task ordering according to scheduling constraints

The hierarchy of a process-description is based on plans: each plan defines a new level in the hierarchy.

• You can view all the plans and their contents at a glance in the tree view.
• The network is more suited for viewing the contents of one plan at a time.

2. The detailed knowledge that is required to enact each component task is entered as task attributes.

Each task type is defined by sets of generic and specific attributes. On the left side in the above screen capture is a set of fields where the author can enter values for the generic attributes of the selected task (here, an enquiry). On the right side is a set of fields that represent the distinguishing attributes of the task type.

Once the PROforma application is developed, it can be tested in the Tallis Tester.