A.10 Graphic Development Environment

Common Prolog includes a graphic environment for users with bitmap displays. The environment consists of a specialized listener and graphic debugging tools. With the debugging tools it is possible to step through a program at the source level and control the 4-port debugger using the mouse. Call trees for predicates may also be displayed and manipulated.

The specialized listener provides mouse control over:

• File editing, compiling, consulting and reconsulting
• Debugging control flow (creep, leap, skip, etc.)
• Leashing of debugging ports
• The addition and deletion of spy points.

The Logic Listener interaction is similar to a normal Lisp Listener and will accept normal Lisp expressions except that:

1. Any expression that can be interpreted as Common Prolog will be handled by the Logic subsystem.
2. Any line beginning with `?-' is read as Edinburgh syntax.
3. If a line consisting of just `?-' is entered, the Logic Listener will go into an Edinburgh (erqp) loop.