smarty/docs/en/programmers/plugins/plugins-functions.xml

<?xml version="1.0" encoding="iso-8859-1"?>
<!-- $Revision$ -->
   <sect1 id="plugins.functions"><title>Template Functions</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>void <function>smarty_function_<replaceable>name</replaceable></function></funcdef>
      <paramdef>array <parameter>$params</parameter></paramdef>
      <paramdef>object <parameter>&amp;$smarty</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     All attributes passed to template functions from the template are
     contained in the <parameter>$params</parameter> as an associative
     array.
    </para>
    <para>
	 The output (return value) of the function will be substituted in place of the
     function tag in the template (<function>fetch</function> function, for
     example). Alternatively, the function can simply perform some other
     task without any output (<function>assign</function> function).
    </para>
    <para>
     If the function needs to assign some variables to the template or use
     some other Smarty-provided functionality, it can use the supplied
     <parameter>$smarty</parameter> object to do so.
    </para>
    <para>
     See also:
     <link linkend="api.register.function">register_function()</link>,
     <link linkend="api.unregister.function">unregister_function()</link>.
    </para>
    <para>
     <example>
      <title>function plugin with output</title>
      <programlisting role="php">
<![CDATA[
<?php
/*
 * Smarty plugin
 * -------------------------------------------------------------
 * File:     function.eightball.php
 * Type:     function
 * Name:     eightball
 * Purpose:  outputs a random magic answer
 * -------------------------------------------------------------
 */
function smarty_function_eightball($params, &$smarty)
{
    $answers = array('Yes',
                     'No',
                     'No way',
                     'Outlook not so good',
                     'Ask again soon',
                     'Maybe in your reality');

    $result = array_rand($answers);
    return $answers[$result];
}
?>
]]>
</programlisting>
     </example>
    </para>
    <para>
     which can be used in the template as:
    </para>
    <programlisting>
Question: Will we ever have time travel?
Answer: {eightball}.
    </programlisting>
    <para>
     <example>
      <title>function plugin without output</title>
      <programlisting role="php">
<![CDATA[
<?php
/*
 * Smarty plugin
 * -------------------------------------------------------------
 * File:     function.assign.php
 * Type:     function
 * Name:     assign
 * Purpose:  assign a value to a template variable
 * -------------------------------------------------------------
 */
function smarty_function_assign($params, &$smarty)
{
    if (empty($params['var'])) {
        $smarty->trigger_error("assign: missing 'var' parameter");
        return;
    }

    if (!in_array('value', array_keys($params))) {
        $smarty->trigger_error("assign: missing 'value' parameter");
        return;
    }

    $smarty->assign($params['var'], $params['value']);
}
?>
]]>
      </programlisting>
     </example>
    </para>
  </sect1>

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