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

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   <sect1 id="plugins.modifiers"><title>Modifiers</title>
    <para>
     Modifiers are little functions that are applied to a variable in the
     template before it is displayed or used in some other context.
     Modifiers can be chained together.
    </para>
    <funcsynopsis>
     <funcprototype>
      <funcdef>mixed <function>smarty_modifier_<replaceable>name</replaceable></function></funcdef>
      <paramdef>mixed <parameter>$value</parameter></paramdef>
      <paramdef>[mixed <parameter>$param1</parameter>, ...]</paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     The first parameter to the modifier plugin is the value on which
     the modifier is supposed to operate. The rest of the parameters can be
     optional, depending on what kind of operation is supposed to be
     performed.
    </para>
    <para>
     The modifier has to return the result of its processing.
    </para>
    <para>
     See also
     <link linkend="api.register.modifier">register_modifier()</link>,
     <link linkend="api.unregister.modifier">unregister_modifier()</link>.
    </para>
    <example>
     <title>simple modifier plugin</title>
     <para>
      This plugin basically aliases one of the built-in PHP functions. It
      does not have any additional parameters.
     </para>
     <programlisting role="php">
<![CDATA[
<?php
/*
 * Smarty plugin
 * -------------------------------------------------------------
 * File:     modifier.capitalize.php
 * Type:     modifier
 * Name:     capitalize
 * Purpose:  capitalize words in the string
 * -------------------------------------------------------------
 */
function smarty_modifier_capitalize($string)
{
    return ucwords($string);
}
?>
]]>
</programlisting>
    </example>
    <para></para>
    <example>
     <title>more complex modifier plugin</title>
     <programlisting role="php">
<![CDATA[
<?php
/*
 * Smarty plugin
 * -------------------------------------------------------------
 * File:     modifier.truncate.php
 * Type:     modifier
 * Name:     truncate
 * Purpose:  Truncate a string to a certain length if necessary,
 *           optionally splitting in the middle of a word, and 
 *           appending the $etc string.
 * -------------------------------------------------------------
 */
function smarty_modifier_truncate($string, $length = 80, $etc = '...',
                                  $break_words = false)
{
    if ($length == 0)
        return '';

    if (strlen($string) > $length) {
        $length -= strlen($etc);
        $fragment = substr($string, 0, $length+1);
        if ($break_words)
            $fragment = substr($fragment, 0, -1);
        else
            $fragment = preg_replace('/\s+(\S+)?$/', '', $fragment);
        return $fragment.$etc;
    } else
        return $string;
}
?>
]]>
     </programlisting>
    </example>
   </sect1>

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