value being 1

If the former is true, then the indicator variable for that column is set to -1 which results in the column being updated with the null value.

如果是前一种情况，那么该列的指示符变量被设置为- 1，这导致该列被更新为空值。

The most notable change from XPath 1.0 to XPath 2.0 is the introduction of a much richer type system: Every value is now a sequence, with a single value being treated as a sequence of length 1.

XPath 1.0到XPath 2.0最引人注意的一个改变是引入了更加丰富的类型系统：每个值现在都是一个序列，一个单一的值将被视为长度为1的序列。

[Request command] is also 1 byte long, and its value is set based on the type of registers being addressed. For reading register values.

[request command]的长度也是一个字节，它的值基于正被寻址的寄存器的类型设置。