$ret = (($i, $j, $k)=(5,6,8,9));        #evaluates to the number of elements on the right side list --- 4
if( ($k, $v) = ( 1, 0 ) )               #evaluates to the number of elements on the right side list --- 2, thus evaluates to TRUE
while ( ($key, $value) = each %map )    #still evaluates to the number of elements on the right side hash