Experiments with Prolog imports and exports from modules

bar.prolog

:- module(bar, [ bar_a/0 ]).

do_import(TargetModule) :-
    %TargetModule:use_module(bar, [bar_a/0]).
    %TargetModule:import(bar:bar_a/0).
    TargetModule:assert((bar_a :- writeln("Asserted bar_a/0"))).

bar_a :-
    writeln("Inside bar_a/0").

foo.prolog

:- module(foo, []).

main :-
    writeln("Loading bar module"),
    load_files(bar,[if(not_loaded),must_be_module(true),imports([])]),

    writeln("We don't have bar_a/0 yet"),
    \+ current_predicate(foo:bar_a/0),

    writeln("Asking bar to perform an import"),
    bar:do_import(foo),

    writeln("We do have bar_a/0 now"),
    current_predicate(foo:bar_a/0),

    writeln("Calling bar_a/0"),
    bar_a.