Loads the specified Prolog source and/or object file(s) into memory, if not already loaded and up to date.
file_spec or list of file_spec, must be ground
A file specification or a list of file specifications; extension optional.
The recommended style is to use this predicate for non-module files only, but if any module files are encountered, then their public predicates are imported.
This predicate is defined as if by:
ensure_loaded(Files) :- load_files(Files, [if(changed)]).