xml - 如何确定 XPath 中的嵌套级别？

Question

在以下示例中，我想使用 XPath (2.0) 表达式确定节点的“嵌套级别”。这个“嵌套级别”将是连续后代的数量，例如如果存在“span/span/span”，则为 3。预期的嵌套级别在注释中给出:

<?xml version="1.0" encoding="UTF-8"?>
<text>
    <div>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean commodo ligula eget
        dolor. Aenean massa.
        <span><!--nesting level:2-->Cum sociis natoque penatibus et magnis dis parturient montes,
            nascetur ridiculus mus.
            <span><!--nesting levels:1-->Donec quam felis, ultricies nec, pellentesque eu, pretium quis, sem.
                <span><!--nesting levels:0-->Nulla consequat massa quis enim.</span>
            </span>
            <span><!--nesting levels:0-->Donec pede justo, fringilla vel, aliquet nec, vulputate eget, arcu.</span>
            In enim justo, rhoncus ut, imperdiet a, venenatis vitae, justo.
        </span>
        <span><!--nesting levels:0-->Nullam dictum felis eu pede mollis pretium. Integer tincidunt. Cras dapibus. Vivamus
            elementum semper nisi.
        </span>
        <span><!--nesting levels:0-->Aenean vulputate eleifend tellus. Aenean leo ligula,
            porttitor eu, consequat vitae, eleifend ac, enim. Aliquam lorem ante, dapibus in, viverra
            quis, feugiat a, tellus.
        </span>
    </div>
    <div>Phasellus viverra nulla ut metus varius laoreet.
        <span><!--nesting levels:0-->Quisque rutrum. Aenean imperdiet. Etiam ultricies nisi vel augue.
        </span>
        <span><!--nesting levels:2-->Curabitur ullamcorper ultricies nisi.
            <span><!--nesting levels:0-->Nam eget dui.</span>
            Etiam rhoncus.
            <span><!--nesting levels:1-->Maecenas tempus, tellus eget condimentum rhoncus, sem quam semper libero, sit amet
                adipiscing sem neque sed ipsum.
                <span><!--nesting levels:0-->Nam quam nunc, blandit vel, luctus pulvinar, hendrerit id, lorem.</span>
                <span><!--nesting levels:0-->Maecenas nec odio et ante tincidunt tempus.</span>
                Donec vitae sapien ut libero venenatis faucibus.
                <span><!--nesting levels:0-->Nullam quis ante.</span>
            </span>
            Etiam sit amet orci eget eros faucibus tincidunt. Duis leo. Sed fringilla mauris sit amet
            nibh.
        </span>
        Donec sodales sagittis magna.
    </div>
</text>

现在，我尝试了 count(descendant::span)) ，但很明显，这也将包括任何 sibling ，并且在许多情况下会产生错误的结果。我也试过 count(descendant::span[1]))和 count(descendant::span[position() = 1])) ，这也给出了错误的结果。我还不知道如何从总数中排除 sibling 的数量。任何提示表示赞赏。

Answer 1

在 XSLT 中，我通过表达式获得了正确的值

            max(
              for $leaf in descendant-or-self::span[not(span)]
              return count($leaf/ancestor-or-self::span except ancestor-or-self::span)
            )

例如样式表

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:xs="http://www.w3.org/2001/XMLSchema"
    exclude-result-prefixes="xs"
    version="2.0">

    <xsl:template match="@* | node()">
        <xsl:copy>
            <xsl:apply-templates select="@* | node()"/>
        </xsl:copy>
    </xsl:template>

    <xsl:template match="span">
        <xsl:copy>
            <xsl:attribute name="nesting-level"
                select=" 
                max(
                  for $leaf in descendant-or-self::span[not(span)]
                  return count($leaf/ancestor-or-self::span except ancestor-or-self::span)
                )"/>
            <xsl:apply-templates select="@* | node()"/>
        </xsl:copy>
    </xsl:template>

</xsl:stylesheet>

我得到输出

<?xml version="1.0" encoding="UTF-8"?><text>
    <div>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean commodo ligula eget
        dolor. Aenean massa.
        <span nesting-level="2"><!--nesting level:2-->Cum sociis natoque penatibus et magnis dis parturient montes,
            nascetur ridiculus mus.
            <span nesting-level="1"><!--nesting levels:1-->Donec quam felis, ultricies nec, pellentesque eu, pretium quis, sem.
                <span nesting-level="0"><!--nesting levels:0-->Nulla consequat massa quis enim.</span>
            </span>
            <span nesting-level="0"><!--nesting levels:0-->Donec pede justo, fringilla vel, aliquet nec, vulputate eget, arcu.</span>
            In enim justo, rhoncus ut, imperdiet a, venenatis vitae, justo.
        </span>
        <span nesting-level="0"><!--nesting levels:0-->Nullam dictum felis eu pede mollis pretium. Integer tincidunt. Cras dapibus. Vivamus
            elementum semper nisi.
        </span>
        <span nesting-level="0"><!--nesting levels:0-->Aenean vulputate eleifend tellus. Aenean leo ligula,
            porttitor eu, consequat vitae, eleifend ac, enim. Aliquam lorem ante, dapibus in, viverra
            quis, feugiat a, tellus.
        </span>
    </div>
    <div>Phasellus viverra nulla ut metus varius laoreet.
        <span nesting-level="0"><!--nesting levels:0-->Quisque rutrum. Aenean imperdiet. Etiam ultricies nisi vel augue.
        </span>
        <span nesting-level="2"><!--nesting levels:2-->Curabitur ullamcorper ultricies nisi.
            <span nesting-level="0"><!--nesting levels:0-->Nam eget dui.</span>
            Etiam rhoncus.
            <span nesting-level="1"><!--nesting levels:1-->Maecenas tempus, tellus eget condimentum rhoncus, sem quam semper libero, sit amet
                adipiscing sem neque sed ipsum.
                <span nesting-level="0"><!--nesting levels:0-->Nam quam nunc, blandit vel, luctus pulvinar, hendrerit id, lorem.</span>
                <span nesting-level="0"><!--nesting levels:0-->Maecenas nec odio et ante tincidunt tempus.</span>
                Donec vitae sapien ut libero venenatis faucibus.
                <span nesting-level="0"><!--nesting levels:0-->Nullam quis ante.</span>
            </span>
            Etiam sit amet orci eget eros faucibus tincidunt. Duis leo. Sed fringilla mauris sit amet
            nibh.
        </span>
        Donec sodales sagittis magna.
    </div>
</text>