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.. rst-class:: align-right

directive

.. index:: pair: mode/2; Directive .. _directives_mode_2:

mode/2

Description

::

mode(Mode, NumberOfProofs)

Most predicates can be used with several instantiations modes. This directive enables the specification of each :ref:`instantiation mode <predicates_mode_instantiation>` and the corresponding :ref:`number of proofs <predicates_mode_number_of_proofs>` (but not necessarily distinct solutions). The instantiation mode of each argument can include type information. You may also use this directive for documenting grammar rule non-terminals.

Template and modes

::

mode(+predicate_mode_term, +number_of_proofs) mode(+non_terminal_mode_term, +number_of_proofs)

Examples

::

:- mode(atom_concat(-atom, -atom, +atom), one_or_more). :- mode(atom_concat(+atom, +atom, -atom), one).

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

:- mode(solve(+callable, -list(atom)), zero_or_one).

.. seealso::

:ref:directives_info_2, :ref:methods_predicate_property_2