The debugger will stop at the first traceable port.
This is not actually a predicate but a toplevel-command.
[eclipse 1]: [user]. p :- true, writeln(hello). user compiled traceable 68 bytes in 0.00 seconds Yes (0.01s cpu) [eclipse 2]: spy writeln/1. spypoint added to sepia_kernel:writeln/1. Debugger switched on - leap mode Yes (0.00s cpu) [eclipse 3]: trace. Debugger switched on - creep mode [eclipse 4]: p. (1) 1 CALL p %> creep S+(2) 2 CALL writeln(hello) %> creep hello S+(2) 2 EXIT writeln(hello) %> creep (1) 1 EXIT p %> creep Yes (0.00s cpu) [eclipse 5]: debug. Debugger switched on - leap mode [eclipse 9]: p. S+(2) 2 CALL writeln(hello) %> creep hello S+(2) 2 EXIT writeln(hello) %> creep (1) 1 EXIT p %> creep Yes (0.00s cpu)