10.34.4.2 Tracing

Tracing is enabled with the chr_trace/0 predicate and disabled with the chr_notrace/0 predicate.

When enabled, the tracer will step through the call, exit, fail, wake and apply ports, accepting debug commands, and simply write out the other ports.

The following debug commands are currently supported:

     CHR debug options:
     
             <cr>    creep           c       creep
             s       skip
             g       ancestors
             n       nodebug
             b       break
             a       abort
             f       fail
             ?       help            h       help

Their meaning is:

creep
Step to the next port.
skip
Skip to exit port of this call or wake port.
ancestors
Print list of ancestor call and wake ports.
nodebug
Disable the tracer.
break
Enter a recursive Prolog toplevel. See break/0.
abort
Exit to the toplevel. See abort/0.
fail
Insert failure in execution.
help
Print the above available debug options.

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