check:valid_string_goal(:Goal)Declare that calls to Goal are safe. The module qualification
is the actual module in which Goal is defined. For example, a
call to format/3
is resolved by the predicate system:format/3.
and the code below specifies that the second argument may be a string
(system predicates that accept strings are defined in the library).
:- multifile check:valid_string_goal/1.
check:valid_string_goal(system:format(_,S,_)) :- string(S).