compiler.pl:     -> assert(create_tracer)
compiler.pl:   retractall(create_tracer).
compiler.pl:   retractall(create_tracer),		% just to make sure no create_tracer
compiler.pl:   ( create_tracer
compiler.pl:   ( create_tracer
compiler.pl:   ( create_tracer
compiler.pl:   ( create_tracer
delay.pl:   ( create_tracer
toplev.pl::- dynamic create_tracer/0.
toplev.pl:   retractall(create_tracer),
toplev.pl:   assert(create_tracer),
toplev.pl:   retractall(create_tracer).
