..
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   Copyright 1998-2022 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.
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       http://www.apache.org/licenses/LICENSE-2.0

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.. index:: pair: sender/1; Built-in method
.. _methods_sender_1:

``sender/1``
============

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

::

   sender(Sender)

Returns the object that has sent the message under processing. This
private method is translated into a unification between its argument and
the corresponding implicit context argument in the predicate clause making
the call. This unification occurs at the clause head when the argument
is not instantiated (the most common case).

Modes and number of proofs
--------------------------

::

   sender(?object_identifier) - zero_or_one

Errors
------

(none)

Examples
--------

::

   % after compilation, the write/1 call will
   % be the first goal on the clause body
   test :-
       sender(Sender),
       write('executing a method to answer a message sent by '),
       writeq(Sender), nl.

.. seealso::

   :ref:`methods_context_1`,
   :ref:`methods_parameter_2`,
   :ref:`methods_self_1`,
   :ref:`methods_this_1`
