..
   This file is part of Logtalk <https://logtalk.org/>  
   SPDX-FileCopyrightText: 1998-2023 Paulo Moura <pmoura@logtalk.org>
   SPDX-License-Identifier: Apache-2.0

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.


.. rst-class:: align-right

**directive**

.. index:: pair: multifile/1; Directive
.. _directives_multifile_1:

``multifile/1``
===============

Description
-----------

::

   multifile(Name/Arity)
   multifile((Name/Arity, ...))
   multifile([Name/Arity, ...])

   multifile(Entity::Name/Arity)
   multifile((Entity::Name/Arity, ...))
   multifile([Entity::Name/Arity, ...])

   multifile(Module:Name/Arity)
   multifile((Module:Name/Arity, ...))
   multifile([Module:Name/Arity, ...])

   multifile(Name//Arity)
   multifile((Name//Arity, ...))
   multifile([Name//Arity, ...])

   multifile(Entity::Name//Arity)
   multifile((Entity::Name//Arity, ...))
   multifile([Entity::Name//Arity, ...])

   multifile(Module:Name//Arity)
   multifile((Module:Name//Arity, ...))
   multifile([Module:Name//Arity, ...])

Declares :term:`multifile <multifile predicate>` predicates and multifile
grammar rule non-terminals. In the case of object or category multifile
predicates, the predicate (or non-terminal) must also have a
:term:`scope directive <predicate scope directive>` in the object or category
holding its *primary declaration* (i.e. the declaration without the
``Entity::`` prefix). Entities holding multifile predicate primary
declarations must be compiled and loaded prior to any entities contributing
with clauses for the multifile predicates (to prevent using multifile
predicates to break entity encapsulation).

Protocols cannot declare or define multifile predicates as protocols cannot
contain predicate definitions.

.. warning::

   Some backend Prolog compilers declare the atom ``multifile`` as an
   operator for a lighter syntax. But this makes the code non-portable
   and is therefore a practice best avoided.

Template and modes
------------------

::

   multifile(+qualified_predicate_indicator_term)
   multifile(+qualified_non_terminal_indicator_term)

Examples
--------

::

   :- multifile(table/3).
   :- multifile(user::hook/2).

.. seealso::

   :ref:`directives_public_1`,
   :ref:`directives_protected_1`,
   :ref:`directives_private_1`,
   :ref:`methods_predicate_property_2`
