..
   This file is part of Logtalk <https://logtalk.org/>  
   Copyright 1998-2023 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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   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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.. rst-class:: align-right

**directive**

.. index:: pair: else/0; Directive
.. _directives_else_0:

``else/0``
==========

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

::

   else

Starts an *else* branch when performing conditional compilation. The
code following this directive is compiled iff the goal in the matching
:ref:`directives_if_1` or :ref:`directives_elif_1` directive is false.

Template and modes
------------------

::

   else

Examples
--------

An example where a hypothetic application would have some limitations
that the user should be made aware when running on a backend Prolog
compiler with bounded arithmetic:

::

   :- if(current_prolog_flag(bounded, true)).

       :- initialization(
           logtalk::print_message(warning,app,bounded_arithmetic)
       ).
   
   :- else.

       :- initialization(
           logtalk::print_message(comment,app,unbounded_arithmetic)
       ).

   :- endif.

.. seealso::

   :ref:`directives_elif_1`,
   :ref:`directives_endif_0`,
   :ref:`directives_if_1`
