occur check support¶

This is a SWI-Prolog implementation of the corresponding Quintus library, based on the generalised arg//33 predicate of SWI-Prolog.

• prolog::sub_var/2
• prolog::sub_term/2
• prolog::occurrences_of_var/3
• prolog::occurrences_of_term/3
• prolog::free_of_var/2
• prolog::free_of_term/2
• prolog::contains_var/2
• prolog::contains_term/2