function "and"  ( l : std_ulogic; r : std_ulogic ) return UX01 is
begin
	return (and_table(l, r));
end "and";

function "and"  ( l,r : std_logic_vector ) return std_logic_vector is
	alias lv : std_logic_vector ( 1 to l'LENGTH ) is l;
	alias rv : std_logic_vector ( 1 to r'LENGTH ) is r;
	variable result : std_logic_vector ( 1 to l'LENGTH );
begin
	if ( l'LENGTH /= r'LENGTH ) then
		assert FALSE
		report "arguments of overloaded 'and' operator are not of the same length"
		severity FAILURE;
	else
		for i in result'RANGE loop
			result(i) := and_table (lv(i), rv(i));
		end loop;
	end if;
	return result;
end "and";