added docs for php-functions as modifiers

docs/designers.sgml

@@ -490,6 +490,27 @@ Topic: {$topic|truncate:40:"..."}
       <literal>{$articleTitle|@count}</literal> (this will print out the number of
       elements in the $articleTitle array.)
      </para>
+     <para>
+      Modifiers can be autoloaded from your <link
+      linkend="variable.plugins.dir">$plugins_dir</link> (also see:
+      <link linkend="plugins.naming.conventions">Naming
+      Conventions</link>) or can be registered explicitely (see: <link
+      linkend="api.register.modifier">register_modifier</link>). Additionally
+      all php-functions can be used as modifiers implicitely. (The
+      <literal>@count</literal>-example above actually uses php's
+      count-function and not a smarty-modifier). Using php-functions
+      as modifiers has two little pitfalls: First: Sometimes the order
+      of the function-parameters is not the desirable one
+      (<literal>{"%2.f"|sprintf:$float}</literal> actually works, but
+      asks for the more intuitive <literal>{For example:
+      $float|string_format:"%2.f"}</literal> that is provided by the
+      Smarty distribution). Second: with <link
+      linkend="variable.security">$security</link> turned on all
+      php-functions that are to be used as modifiers have to be
+      declared trusted in the <link
+      linkend="variable.security.settings">
+      $security_settings['MODIFIER_FUNCS']</link>-array.
+     </para>
 
       <sect1 id="language.modifier.capitalize">
        <title>capitalize</title>

docs/programmers.sgml

@@ -457,7 +457,6 @@ $smarty->autoload_filters = array('pre' => array('trim', 'stamp'),
      </sect1>
      <sect1 id="variable.request.use.auto.globals">
       <title>$request_use_auto_globals</title>
-
       <para>
 	   Specifies if Smarty should use php's $HTTP_*_VARS[]
 	   ($request_use_auto_globals=false which is the default value) or
@@ -467,7 +466,6 @@ $smarty-&gt;autoload_filters = array('pre' =&gt; array('trim', 'stamp'),
 	   linkend="variable.request.vars.order">variable.request.vars.order
 	   </link> has no effect but php's configuration value
 	   <literal>gpc_order</literal> is used.
-
       </para>
      </sect1>
      <sect1 id="variable.compile.id">
@@ -2495,9 +2493,10 @@ $smarty->default_template_handler_func = 'make_template';
     depends on the order in which they are registered or loaded.
    </para>
    <para>
-    There is only one plugins directory (for performance reasons). To
+    The <link linkend="variable.plugins.dir">plugins directory</link>
-    install a plugin, simply place it in the directory and Smarty will use
+    can be a string containing a path or an array containing multiple
-    it automatically.
+    paths. To install a plugin, simply place it in one of the
+    directories and Smarty will use it automatically.
    </para>
   </sect1>