mode/2

Description

mode(Mode, Number_of_solutions)

Most predicates can be used with several instantiations modes. This directive enables the specification of each instantiation mode and the corresponding number of solutions/proofs. You may also use this directive for documenting grammar rule non-terminals.

Template and modes

mode(+predicate_mode_term, +number_of_solutions)
mode(+non_terminal_mode_term, +number_of_solutions)

Examples

:- mode(append(-, -, +), zero_or_more).

:- mode(append(+list, +list, -list), zero_or_one).

:- mode(var(@term), zero_or_one).

:- mode(arg(-, -, +), error).