..
   This file is part of Logtalk <https://logtalk.org/>  
   Copyright 1998-2020 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.
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.. 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`
