append_by_ref

This is used to append values to the templates by reference. If you append a variable by reference then change its value, the appended value sees the change as well. For objects, append_by_ref() also avoids an in-memory copy of the appended object. See the PHP manual on variable referencing for an in-depth explanation. If you pass the optional third parameter of true, the value will be merged with the current array instead of appended.

// appending name/value pairs
$smarty->append_by_ref("Name",$myname);
$smarty->append_by_ref("Address",$address);