SWI-Prolog -- check:valid_string

Documentation
- Reference manual
  - SWI-Prolog extensions
    - The string type and its double quoted syntax
      - Predicates to support adapting code for double quoted strings
        
        list_strings/0
        
        string_predicate/1
        
        valid_string_goal/1
- Packages

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).