Debugging Mercury Programs

[Ralph Becket]

While the Mercury compiler does seem to produce the most helpful error
messages in the world, the absense of a debugger and `tracing' IO
in nondeterministic predicates would seem to make finding logical bugs
very difficult.

I was wondering what the Mercury developers and people developing
applications using Mercury currently use when debugging.  Is

	--generate-prolog sicstus

sufficient for the task (I haven't tried it, but suspect that a
good deal of name mangling and code reordering occurs twixt Mercury
and Prolog).  On the other hand, do people use some nasty impure
library for tracing IO in non-deterministic predicates, something of
the form

:- pred trc_msg(string).
:- mode trc_msg(in) is semidet.

:- pragma c_code(
	trc_msg(Msg::in),
	may_call_mercury,
"{
	printf("\ntrc_msg: %s\n", Msg);
}").

Of course, I may be missing something obvious here...  While I'm on
the subject, is anybody working on a Mercury level debugger?

Cheers,

Ralph

-- 
Ralph Becket  |  rwab1 at cam.sri.com  |  http://www.cam.sri.com/people/becket.html