prolog:called_by(+Goal,
-Called)Goal is a non-var subgoal appearing in the called object
(typically a clause body). If it succeeds it must return a list of goals
called by Goal. As a special construct, if a term Callable+N
is returned, N variable arguments are added to Callable
before further processing. For simple meta-calls a single fact suffices.
Complex rules as used in the library(html_write) library
provided by the HTTP package examine the arguments and create a list of
called objects.
The current system cannot deal with the same name/arity in different
modules that behave differently with respect to called arguments.