为什么在非原子化的序列上不同的值不产生不同的值？

Question

为什么

(<benefitStartDate>20170101</benefitStartDate>,<benefitEndDate>20170301</benefitEndDate>,
<benefitStartDate>20170101</benefitStartDate>,<benefitEndDate>20170501</benefitEndDate>)/distinct-values(.)

产量20170101 20170301 20170101 20170501 (即重复未消除)

但将其应用于序列的原子化版本

distinct-values((20170701,20170301,20170701,20170501))产量

20170701 20170301 20170501

Answer 1

(
  <benefitStartDate>20170101</benefitStartDate>,<benefitEndDate>20170301</benefitEndDate>,
  <benefitStartDate>20170101</benefitStartDate>,<benefitEndDate>20170501</benefitEndDate>
)/distinct-values(.)

与以下情况不同：

distinct-values(
  <benefitStartDate>20170101</benefitStartDate>,<benefitEndDate>20170301</benefitEndDate>,
  <benefitStartDate>20170101</benefitStartDate>,<benefitEndDate>20170501</benefitEndDate>
)

后者返回元素序列的不同值。

您的代码返回这些元素中每个元素的不同值，这类似于调用：

(
  distinct-values(<benefitStartDate>20170101</benefitStartDate>),
  distinct-values(<benefitEndDate>20170301</benefitEndDate>),
  distinct-values(<benefitStartDate>20170101</benefitStartDate>),
  distinct-values(<benefitEndDate>20170501</benefitEndDate>)
)

返回预期结果的另一个变体是：

(
  <benefitStartDate>20170101</benefitStartDate>,<benefitEndDate>20170301</benefitEndDate>,
  <benefitStartDate>20170101</benefitStartDate>,<benefitEndDate>20170501</benefitEndDate>
) => distinct-values()

最好的

迈克尔