How to get a listing of a specific knowledge base?

Question

Suppose that the file foobar.pl in the current working directory contains the following minimal knowledgebase:

foo(bar).
foo(baz).
frobozz.

If I start swi-prolog (by running swipl at the command), and immediately run

?- [foobar].
% foobar compiled 0.00 sec, 4 clauses
true.

?- listing.

...the contents of foobar are lost in a sea of >100 lines of unrelated output.

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How can I limit listing 's output to foobar ?

Alternatively, how can I limit it to contents of those knowledgebases I have explicitly consult ed?

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I did look at the docs for listing/1 and listing/0 , but I could not find anything helpful:

listing/1 List predicates specified by Pred. Pred may be a predicate name (atom), which lists all predicates with this name, regardless of their arity. It can also be a predicate indicator (/ or //), possibly qualified with a module. For example: ?- listing(lists:member/2)..

A listing is produced by enumerating the clauses of the predicate using clause/2 and printing each clause using portray_clause/1. This implies that the variable names are generated (A, B, ... ) and the layout is defined by rules in portray_clause/1.

listing/0 List all predicates from the calling module using listing/1. For example, ?- listing. lists clauses in the default user module and ?- lists:listing. lists the clauses in the module lists.

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Of course, I did try the following useless idea:

?- foobar:listing.
true.

Answer 1

in SWI-Prolog, you can limit the scope of the loaded clauses with the module/2 directive . Ie your file foobar.pl should become (for instance)

:- module(foobar, [foo/1]).

foo(bar).
foo(baz).
frobozz.

Answer 2

You can load the contents of a plain Prolog file into a module easily. For example:

?- fb:consult(foobar).
true

And then call:

?- fb:listing.

foo(bar).
foo(baz).

frobozz.
true.

Or list just a specific predicate:

?- fb:listing(foo/1).
foo(bar).
foo(baz).

true.