.. 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 method

.. index:: pair: consistency_error/3; Built-in method .. _methods_consistency_error_3:

consistency_error/3

Description

::

consistency_error(Consistency, Argument1, Argument2)

Throws a consistency error. Used when two directives or predicate arguments are individually correct but together are not consistent. For example, a predicate and its alias having different arity in a uses/2 directive. This built-in method is declared private and thus cannot be used as a message to an object. Calling this predicate is equivalent to the following sequence of goals:

::

..., context(Context), throw(error(consistency_error(Consistency,Argument1,Argument2), Context)).

This allows the user to generate errors in the same format used by the runtime.

Possible values representing Consistency checks include:

• same_arity
• same_number_of_parameters
• same_number_of_arguments
• same_closure_specification

Modes and number of proofs

::

consistency_error(+atom, @nonvar, @nonvar) - error

Errors

| When called: | consistency_error(Consistency, Argument1, Argument2)

Examples

::

% code that will trigger consistency errors when compiled:

% predicates (and non-terminals) aliases must have the same % arity as the original predicates (and non-terminals) :- uses(list, [ member/2 as in/1 ]).

% meta-predicate templates should be consistent with how closures % are used regarding the number of additional arguments :- public(p/2). :- meta_predicate(p(1, *)).

p(G, A) :- call(G, A, 2).

.. seealso::

:ref:methods_catch_3, :ref:methods_throw_1, :ref:methods_context_1, :ref:methods_instantiation_error_0, :ref:methods_uninstantiation_error_1, :ref:methods_type_error_2, :ref:methods_domain_error_2, :ref:methods_existence_error_2, :ref:methods_permission_error_3, :ref:methods_representation_error_1, :ref:methods_evaluation_error_1, :ref:methods_resource_error_1, :ref:methods_syntax_error_1, :ref:methods_system_error_0