..
   This file is part of Logtalk <https://logtalk.org/>  
   Copyright 1998-2019 Paulo Moura <pmoura@logtalk.org>

   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
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.. index:: current_op/3
.. _methods_current_op_3:

current_op/3
============

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

::

   current_op(Priority, Specifier, Operator)

Enumerates, by backtracking, the visible operators declared for an
object. Operators not declared using a scope directive are not
enumerated.

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

::

   current_op(?operator_priority, ?operator_specifier, ?atom) - zero_or_more

Errors
------

| Priority is neither a variable nor an integer:
|     ``type_error(integer, Priority)``
| Priority is an integer but not a valid operator priority:
|     ``domain_error(operator_priority, Priority)``
| Specifier is neither a variable nor an atom:
|     ``type_error(atom, Specifier)``
| Specifier is an atom but not a valid operator specifier:
|     ``domain_error(operator_specifier, Specifier)``
| Operator is neither a variable nor an atom:
|     ``type_error(atom, Operator)``

Examples
--------

| To enumerate, by backtracking, the local operators or the operators visible in :term:`this`:
|     ``current_op(Priority, Specifier, Operator)``
| To enumerate, by backtracking, the public and protected operators visible in :term:`self`:
|     ``::current_op(Priority, Specifier, Operator)``
| To enumerate, by backtracking, the public operators visible for an explicit object:
|     ``Object::current_op(Priority, Specifier, Operator)``

.. seealso::

   :ref:`methods_current_predicate_1`,
   :ref:`methods_predicate_property_2`,
   :ref:`directives_op_3`
