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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

directive

.. index:: pair: alias/2; Directive .. _directives_alias_2:

alias/2

Description

::

alias(Entity, [Name/Arity as Alias/Arity, ...]) alias(Entity, [Name//Arity as Alias//Arity, ...])

Declares predicate and grammar rule non-terminal :term:`aliases <predicate alias>`. A predicate (non-terminal) alias is an alternative name for a predicate (non-terminal) declared or defined in an extended protocol, an implemented protocol, an extended category, an imported category, an extended prototype, an instantiated class, or a specialized class. Predicate aliases may be used to solve conflicts between imported or inherited predicates. It may also be used to give a predicate (non-terminal) a name more appropriate in its usage context. This directive may be used in objects, protocols, and categories.

Predicate (and non-terminal) aliases are specified using (preferably) the notation Name/Arity as Alias/Arity or, in alternative, the notation Name/Arity::Alias/Arity.

It is also possible to declare predicate and grammar rule non-terminal aliases in implicit qualification directives for sending messages to objects and calling module predicates.

Template and modes

::

alias(@entity_identifier, +list(predicate_indicator_alias)) alias(@entity_identifier, +list(non_terminal_indicator_alias))

Examples

::

% resolve a predicate name conflict: :- alias(list, [member/2 as list_member/2]). :- alias(set, [member/2 as set_member/2]).

% define an alternative name for a non-terminal: :- alias(words, [singular//0 as peculiar//0]).

.. seealso::

:ref:directives_uses_2, :ref:directives_use_module_2, :ref:directives_uses_1