Viewing source / setting breakpoints on term_expansion/2 generated rules

Help!
#1

If I use term_expansion/2 like this:

term_expansion(createWritelnPredicate(PredicateName),
    [
        (NewPredicateHead :- writeln(TextToWriteln))
    ]) :-
        NewPredicateHead =.. [PredicateName, TextToWriteln]
    .
createWritelnPredicate(test99).

Is there a way to view the generated source for the rule test99 in gxref/0? If I click on that name in that tool, it just takes me to the line:

createWritelnPredicate(test99).

not the generated source.

I’m trying to set a breakpoint inside the generated source. Is there a way to do that?

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#2

I won’t call it “generated source”. Source is (IMO) something you wrote. The actual clause is not even in a temporary file. In theory it should be possible to list the generated clause and use that representation to set a breakpoint. That doesn’t exist. In this case I’d simply use ?- spy(test88).

I guess the remark is similar to the other: if you use goal/term expansion to turn a source code into something that lacks a one-to-one mapping between terms in the source code and goals in the final clause(s), you get a poor source level debugging experience. If rewriting merely rewrites goal arguments everything typically keeps working. On more elaborate changes that maintain this one-to-one mapping additional rules can be use to make the debugger work.

#3

Got it, thanks. Yes for this example there are many variables created that aren’t in the original goal so this probably isn’t a great use of the system, at least from a debugging experience perspective.

#4

term_expansion/2 is for facts, rules and directives. Do you assume that
term_expansion/2 is directly called for goals? This post is where I saw the terminology error
for the first time today.

Namely this input here:

is a fact. Its not a goal. You are just expanding a fact via term_expansion/2. If it were a goal you would need to define goal_expansion/2. But you defined term_expansion/2, which is responsible for facts, rules and directives.

#5

Yes, I should have said fact.