{include_php}
Technical Note: 
    {include_php} is pretty much deprecated from Smarty, you can
    accomplish the same functionality via a custom template function.
    The only reason to use {include_php} is if you really have a need to
    quarantine the php function away from the
    plugins
    directory or your
    application code. See the componentized template
    example for details.
   
  {include_php} tags are used to include a php script in your template.
  If security is enabled,
  then the php script must be located in the $trusted_dir path.
  The {include_php} tag must have the attribute
  "file", which contains the path to the included php file, either
  relative to
  $trusted_dir,
  or an absolute path.
 
  By default, php files are only included once even if called
  multiple times in the template. You can specify that it should be
  included every time with the once attribute.
  Setting once to false will include the php script each time it is
  included in the template.
 
  You can optionally pass the assign attribute,
  which will specify a template variable name that the output of
  {include_php} will be assigned to instead of
  displayed.
 
  The smarty object is available as $this within the PHP script that you
  include.
 
| Example 7-13. function {include_php} load_nav.php | 
<?php
 // load in variables from a mysql db and assign them to the template
 require_once("MySQL.class.php");
 $sql = new MySQL;
 $sql->query("select * from site_nav_sections order by name",SQL_ALL);
 $this->assign('sections',$sql->record);
 
 ?>
 | 
 
   Where index.tpl is:
   | {* absolute path, or relative to $trusted_dir *}
{include_php file="/path/to/load_nav.php"}
{foreach item="curr_section" from=$sections}
  <a href="{$curr_section.url}">{$curr_section.name}</a><br />
{/foreach} | 
 | 
  See also {include},
  {php}, {capture}, Template Resources and Componentized
  Templates