/* * call-seq: * dvector.index(number) -> int or nil * * Returns the index of the first object in _dvector_ * <code>==</code> to _number_. Returns <code>nil</code> if * no match is found. * * a = Dvector[ 1, 2, 3, 4, 5, 4, 3, 2 ] * a.index(3) -> 2 * a.index(0) -> nil */ VALUE dvector_index(VALUE ary, VALUE val) {