XSLT 3.0使用xsl:number统计嵌套crewDrillStep下para编号异常问题

我正在尝试为<para>标签添加编号，每个<crewDrillStep>下仅包含一个<para>，<crewDrillStep>本身支持嵌套。原有逻辑在普通场景下运行正常，但只要存在<if>块，编号就会异常连续计数，移除<if>后编号就能正常生成。
我参考Martin的建议更新了示例，目前效果已经非常接近需求，但业务场景中可能存在多个<crewDrill>，且部分场景下二级<para>的编号不需要重启。此外XML中部分带项目符号的para不需要参与编号。

给定XML结构 #

<crew>
    <crewRefCard>
        <title>Expanded Self-Test Procedures </title>
        <crewDrill>
           <if>
              <caseCond>After program stops at test No. 1:</caseCond>
              <crewDrillStep id="d1e21189">
                 <para>RESET switch - ELEC.</para>
              </crewDrillStep>
              <crewDrillStep id="d1e21195">
                 <para>Flip red switches:</para>
                 <crewDrillStep id="d1e21200">
                    <para>Right.</para>
                 </crewDrillStep>
                 <crewDrillStep id="d1e21206">
                    <para>Left.</para>
                 </crewDrillStep>
                 <crewDrillStep id="d1e21212">
                    <para>Rudder.</para>
                 </crewDrillStep>
              </crewDrillStep>
              <crewDrillStep id="d1e21219">
                 <para>Flip orange switch.</para>
                 <crewDrillStep id="d1e21224">
                    <para>Test No. advances to 2.</para>
                 </crewDrillStep>
                 <crewDrillStep id="d1e21230">
                    <para>Yellow caution light - On.</para>
                 </crewDrillStep>
                 <crewDrillStep id="d1e21236">
                    <para>Red warning light - On.</para>
                 </crewDrillStep>
                 <crewDrillStep id="d1e21242">
                    <para>Program stops.</para>
                 </crewDrillStep>
              </crewDrillStep>
        </crewDrill>
    </crewRefCard>
</crew>

所用XSLT模板代码 #

<xsl:template name="para" match="para | notePara | warningAndCautionPara | attentionListItemPara">
    <fo:block text-align="justify">           
        <xsl:choose>
            <xsl:when test="self::para and (parent::crewDrillStep)">
                <fo:block>
                    <xsl:choose>
                        <xsl:when test="count(ancestor::crewDrillStep)=1">
                            <xsl:number from="crewDrill" level="any" count="crewDrillStep"/>
                        </xsl:when>
                        <xsl:when test="count(ancestor::crewDrillStep)=2 ">     
                            <xsl:attribute name="margin-left" select="'.25in'"/>
                            <xsl:number from="crewDrill/crewDrillStep" level="any" count="para[count(ancestor::crewDrillStep) = 2][not(starts-with(normalize-space(.),'•'))]" format="a. "/>
                        </xsl:when>
                        <xsl:when test="count(ancestor::crewDrillStep)=3">
                            <xsl:attribute name="margin-left" select="'.50in'"/>
                            <xsl:number from="crewDrill" count="crewDrillStep" format="(1) "/> 
                        </xsl:when>
                        <xsl:otherwise/>
                    </xsl:choose>
                </fo:block>
                <fo:block>
                    <xsl:apply-templates select="node()" mode="include"/>
                </fo:block>
            </xsl:when>
        </xsl:choose>
    </fo:block>
</xsl:template>

期望输出效果 #

Expanded Self-Test Procedures
After program stops at test No. 1:
1. RESET switch - ELEC.
2. Flip red switches:
    a. Right
    b. Left.
    c. Rudder.
3. Flip orange switch.
    a. Test No. advances to 2.
    b. Yellow caution light - On.
    c. Red warning light - On.
    d. Program stops.

实际输出效果 #

Expanded Self-Test Procedures
After program stops at test No. 1:
1. RESET switch - ELEC.
2. Flip red switches:
    a. Right
    b. Left.
    c. Rudder.
3. Flip orange switch.
    d. Test No. advances to 2.
    e. Yellow caution light - On.
    f. Red warning light - On.
    g. Program stops.

问题 #

如何调整xsl:number配置，实现预期的层级编号效果？

问题核心是二级编号的from属性匹配规则和实际XML结构不符：
原配置中二级para的from="crewDrill/crewDrillStep"要求匹配crewDrill的直接子节点crewDrillStep，但你的XML中crewDrill的直接子节点是<if>，没有符合要求的节点，导致xsl:number默认从文档根节点开始统计所有符合条件的二级para，所以第二个一级步骤下的二级编号就从d开始连续计数了。

调整方案 #

只需要修改二级para对应的xsl:number配置，将from属性改为匹配当前para所属的一级crewDrillStep即可，修改后的完整代码如下：

<xsl:template name="para" match="para | notePara | warningAndCautionPara | attentionListItemPara">
    <fo:block text-align="justify">           
        <xsl:choose>
            <xsl:when test="self::para and (parent::crewDrillStep)">
                <fo:block>
                    <xsl:choose>
                        <xsl:when test="count(ancestor::crewDrillStep)=1">
                            <xsl:number from="crewDrill" level="any" count="crewDrillStep"/>
                        </xsl:when>
                        <xsl:when test="count(ancestor::crewDrillStep)=2 ">     
                            <xsl:attribute name="margin-left" select="'.25in'"/>
                            <!-- 仅修改这一行的from属性 -->
                            <xsl:number from="ancestor::crewDrillStep[count(ancestor::crewDrillStep) = 1]" level="any" count="para[count(ancestor::crewDrillStep) = 2][not(starts-with(normalize-space(.),'•'))]" format="a. "/>
                        </xsl:when>
                        <xsl:when test="count(ancestor::crewDrillStep)=3">
                            <xsl:attribute name="margin-left" select="'.50in'"/>
                            <xsl:number from="crewDrill" count="crewDrillStep" format="(1) "/> 
                        </xsl:when>
                        <xsl:otherwise/>
                    </xsl:choose>
                </fo:block>
                <fo:block>
                    <xsl:apply-templates select="node()" mode="include"/>
                </fo:block>
            </xsl:when>
        </xsl:choose>
    </fo:block>
</xsl:template>

调整说明 #

修改后的from="ancestor::crewDrillStep[count(ancestor::crewDrillStep) = 1]"会向上查找当前para所属的最顶层一级crewDrillStep，统计范围限定在这个一级步骤的内部，每个一级步骤下的二级para都会重新从a开始计数，完全匹配预期效果。如果部分场景下不需要二级编号重启，对应场景保留原from配置即可。

内容的提问来源于stack exchange，提问作者Caroline