function call within function call

Hello, I'm looking for possibly combining two plugins. Depending on the assigned variable {$actype} I want to retrieve related data from a database by using function {get_supplier} and use the result as parameter for function {checkfield} *** The way it worked before (all supplier data in array and assigned as $supplier_default): {checkfield data=$supplier value=$supplier_value default=$supplier_default.$actype} *** The way I'd rather have it to work (but it doesn't): {checkfield data=$supplier value=$supplier_value default=get_supplier($actype)} function smarty_function_get_supplier($params, &$smarty) { /* database query */ $res=array(1,2,3); return $res; } *** Both functions are named right (function.checkfield.php, function.get_supplier.php) in the assigned plugins-directory. Is a function call within a function call possible? What'd be the proper syntax to achieve the desired? Thanks and greetings, Peggy