:sig
DTree* unit_call(String file_name, String function_name, DTree* call_param = null)

:params
file_name : UCE file to load and execute
function_name : name of the function to invoke
call_param : optional, call parameter
return value : DTree* returned from function

:desc
Calls an exported function inside a UCE file.

:Example
// export a function
EXPORT DTree* test_func(DTree* call_param)
{
	print("HELLO FROM TEST FUNCTION");
	return(0);
}
// use that function in another file
unit_call("call_file_funcs.uce", "test_func");

:see
>ob