Question

Is there a built-in predicate or a easy way to remove from the knowledge database of prolog a source files that has already been consulted? I’ve gone through the reference manual and didn’t find any thing that could do that.

Answer 1

You can do it with these procedures which use source_file/1 and source_file/2:

unload_last_source:-
  findall(Source, source_file(Source), LSource),
  reverse(LSource, [Source|_]),
  unload_source(Source).

unload_source(Source):-
  ground(Source),
  source_file(Pred, Source),
  functor(Pred, Functor, Arity),
  abolish(Functor/Arity),
  fail.
unload_source(_).

unload_source/1 abolishes all predicates defined by the input Source file name. Be warned that it needs to be an absolute path.

unload_last_source/0 will retrieve the last consulted file name and unload it.