When a module-file is loaded by load_files/[1,2] or
one of its shorthands (see Read In), by default all the public
predicates of the module-file are imported by the
receiving module. An explicit list of predicates to
import may also be specified.
Name clashes with already existing predicates, local or
imported from other modules, are handled in two different
ways: If the receiving module is the user module, the
user is asked for redefinition of the predicate. For other
receiving modules, a warning is issued and the importation
is canceled. In the first case redefinition silently takes place if the
redefine_warnings Prolog flag has the value off. The
binding of an imported predicate remains, even if the origin
is reloaded or deleted. However, abolish/[1,2] break up the
importation binding. When a module-file is reloaded, a
check is made that the predicates imported by other
modules are still in the public list. If that is not the case, a
warning is issued. Note that an imported predicate may be
re-exported.