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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: elif/1; Directive
.. _directives_elif_1:

``elif/1``
==========

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

::

   elif(Goal)

Supports embedded conditionals when performing conditional compilation.
The code following the directive is compiled iff ``Goal`` is true. The
goal is subjected to :ref:`goal expansion <expansion_expansion>` when the
directive occurs in a source file.

.. warning::

   Conditional compilation goals **cannot** depend on predicate definitions
   contained in the same source file that contains the conditional
   compilation directives (as those predicates only become available after
   the file is successfully compiled and loaded).

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

::

   elif(@callable)

Examples
--------

::

   :- if(current_prolog_flag(double_quotes, codes)).

       ...

   :- elif(current_prolog_flag(double_quotes, chars)).

       ...

   :- elif(current_prolog_flag(double_quotes, atom)).

       ...

   :- endif.

.. seealso::

   :ref:`directives_else_0`,
   :ref:`directives_endif_0`,
   :ref:`directives_if_1`
