如何识别特定元素下具有特定位置的元素

Question

请建议，如何找到 'mfrac' 出现在其第二个子端的 'msup' 元素下。（Mfenced 是 mfenced，当它包含 'mfrac as its descendant, but only when mfrac found under second child position of msup, then should convert to 'mo' 时。）

当 mfrac 在 'msup' 的第一个子边内时，则 'mfenced' 不是需要改变。
当 mfrac 在 'msup' 的 second child 一侧时，则 'mfenced' 是转换为'mo'
否则在'mfenced'内找到'mfrac'，则不需要'mfenced' 改变。

XML:

<article>
<math><mfenced open="(" close=")"><mfrac><mn>1</mn><mn>2</mn></mfrac></mfenced></math>
<math><mfenced open="(" close=")"><msup><mfrac><mn>1</mn><mn>2</mn></mfrac><mn>7</mn></msup></mfenced></math>
<math><mfenced open="(" close=")"><msup><mn>7</mn><mfrac><mn>1</mn><mn>2</mn></mfrac></msup></mfenced></math>
<math><mfenced open="(" close=")"><msup><mrow><mn>7</mn></mrow><mrow><mfrac><mn>1</mn><mn>2</mn></mfrac></mrow></msup></mfenced></math>
</article>

XSLT:

<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

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

<xsl:template match="mfenced">
    <xsl:choose>
        <xsl:when test="not(descendant::mfrac[. is ancestor::msup[1]/*[1]/descendant::*])"><!--checking, whether mfrac not found within first child of 'msup' -->
            <mo><xsl:apply-templates/></mo>
        </xsl:when>
        <xsl:otherwise>
            <xsl:copy><xsl:apply-templates select="@* | node()"/></xsl:copy>
        </xsl:otherwise>
    </xsl:choose>
</xsl:template>
</xsl:stylesheet>

所需结果：

<article>
<math><mfenced open="(" close=")"><mfrac><mn>1</mn><mn>2</mn></mfrac></mfenced></math><!--no need alter, because 'mfrac' found within 'mfenced'-->
<math><mfenced open="(" close=")"><msup><mfrac><mn>1</mn><mn>2</mn></mfrac><mn>7</mn></msup></mfenced></math><!--no need alter, because 'mfrac' found within first child of 'msup' -->
<math><mo><msup><mn>7</mn><mfrac><mn>1</mn><mn>2</mn></mfrac></msup></mo></math><!--Converted to 'MO', because 'mfrac' is under 2nd child of 'msup' -->
<math><mo><msup><mrow><mn>7</mn></mrow><mrow><mfrac><mn>1</mn><mn>2</mn></mfrac></mrow></msup></mo></math><!--Converted to 'MO', because 'mfrac' is under 2nd child of 'msup' -->
</article>

错误信息：

  XPTY0004: A sequence of more than one item is not allowed as the second operand of 'is' (<mn/>, <mn/>)

Answer 1

怎么样：

<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
    <xsl:template match="@*|node()">
        <xsl:copy><xsl:apply-templates select="@* | node()"/></xsl:copy>
    </xsl:template>

    <xsl:template match="mfenced[
        not(mfrac)
        and (
            msup/mfrac[preceding-sibling::*]
            or msup//mfrac[not(parent::msup)]
        )
    ]">
        <mo><xsl:apply-templates/></mo> 
    </xsl:template>
</xsl:stylesheet>

如何识别特定元素下具有特定位置的元素

How to identify a element present under specific element with specific place

xslt

xslt-2.0