..
   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

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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.

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 fully 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`
