case castString:
		s, err := stringCast(v)
		return FromString(s), err

	case castTimestamp:
		t, err := timestampCast(v)
		return FromTimestamp(t), err

	case castBool:
		b, err := boolCast(v)
		return FromBool(b), err

	case castDecimal, castNumeric:
		fallthrough

	default:
		return nil, errUnimplementedCast
	}
}

func intCast(v *Value) (int64, error) {