.. This file is part of Logtalk https://logtalk.org/ SPDX-FileCopyrightText: 1998-2024 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

control construct

.. index:: pair: (^^)/1; Control construct .. _control_call_super_1:

(^^)/1

Description

::

^^Predicate

Calls an imported or inherited predicate definition. The call fails if the predicate is declared but there is no imported or inherited predicate definition (as per the :term:`closed-world assumption`). This control construct may be used within objects or categories in the body of a predicate definition.

This control construct preserves the implicit execution context :term:self and :term:sender arguments (plus the meta-call context and coinduction stack when applicable) when calling the inherited (or imported) predicate definition.

The lookups for the predicate declaration and the predicate definition are performed using a depth-first strategy. Depending on the value of the :ref:`optimize <flag_optimize>` flag, these lookups are performed at compile time when the predicate is static and sufficient information is available. When the lookups are performed at runtime, a caching mechanism is used to improve performance in subsequent calls. See the User Manual section on :ref:`performance <performance_performance>` for details.

When the call is made from within an object, the lookup for the predicate definition starts at the imported categories, if any. If an imported predicate definition is not found, the lookup proceeds to the ancestor objects. Calls from predicates defined in complementing categories lookup inherited definitions as if the calls were made from the complemented object, thus allowing more comprehensive object patching. For other categories, the predicate definition lookup is restricted to the extended categories.

The called predicate should be declared :ref:`public <directives_public_1>` or :ref:`protected <directives_protected_1>`. It may also be declared :ref:`private <directives_private_1>` if within the scope of the entity where the method making the call is defined.

This control construct is a generalization of the Smalltalk super keyword to take into account Logtalk support for prototypes and categories besides classes.

Modes and number of proofs

::

^^+callable - zero_or_more

Errors

| Predicate is a variable: | instantiation_error | Predicate is neither a variable nor a callable term: | type_error(callable, Predicate) | Predicate, with predicate indicator Name/Arity, is declared private: | permission_error(access, private_predicate, Name/Arity) | Predicate, with predicate indicator Name/Arity, is not declared: | existence_error(predicate_declaration, Name/Arity)

Examples

::

% specialize the inherited definition % of the init/0 predicate: init :- assertz(counter(0)), ^^init.

.. seealso::

:ref:control_send_to_object_2, :ref:control_send_to_self_1, :ref:control_delegate_message_1