.. 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

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.. rst-class:: align-right

built-in predicate

.. index:: pair: extends_protocol/2-3; Built-in predicate .. _predicates_extends_protocol_2_3:

extends_protocol/2-3

Description

::

extends_protocol(Protocol, ParentProtocol) extends_protocol(Protocol, ParentProtocol, Scope)

Enumerates, by backtracking, all pairs of protocols such that the first one extends the second. The relation scope is represented by the atoms public, protected, and private.

Modes and number of proofs

::

extends_protocol(?protocol_identifier, ?protocol_identifier) - zero_or_more extends_protocol(?protocol_identifier, ?protocol_identifier, ?scope) - zero_or_more

Errors

| Protocol is neither a variable nor a valid protocol identifier: | type_error(protocol_identifier, Protocol) | ParentProtocol is neither a variable nor a valid protocol identifier: | type_error(protocol_identifier, ParentProtocol) | Scope is neither a variable nor an atom: | type_error(atom, Scope) | Scope is an atom but an invalid entity scope: | domain_error(scope, Scope)

Examples

::

% enumerate the protocols extended by the listp protocol: | ?- extends_protocol(listp, Protocol).

% enumerate protocols that privately extend the termp protocol: | ?- extends_protocol(Protocol, termp, private).

.. seealso::

:ref:predicates_current_protocol_1, :ref:predicates_implements_protocol_2_3, :ref:predicates_conforms_to_protocol_2_3