xslt-1.0 - 使用 xsl :for-each 访问谓词中的当前节点

Question

我一直在寻找如何访问当前节点，同时使用 xsL:for-each 迭代节点集合。这是我的 XML:

<events>
    <event>
        <date>
            <year>2012</year>
            <month>July</month>
        </date>
        <description>...</description>
    </event>
    <!-- more events -->
</events>

我试图实现的是这样的 HTML 表示:

<h2>2012</h2>
<dl>
    <dt>July</dt>
    <dd>One of these for every event with year=2012 and month=July</dd>

    <dt>August</dt>
    <!-- ... -->
</dl>
<h2>2013</h2>
<!-- ... -->

我使用 XPath 表达式来获取所有不同的年份，然后使用参数 $year 和 $events 调用名为 year 的模板来迭代它们。获取 $year 的值很容易，但我很难找到正确的事件。以下内容不起作用，可能是因为第二个谓词中的 . 引用了正在为该谓词测试的 event。但如何访问其中的年份？

<xsl:template match="events">
<xsl:for-each select="event[not(date/year=preceding-sibling::event/date/year)]/date/year">
<xsl:call-template name="year">
    <xsl:with-param name="year" select="." />
    <xsl:with-param name="events" select="event[date/year=.]" />
</xsl:call-template>
</xsl:for-each>
</xsl:template>

非常感谢!

PS:必须使用 XPath 和 XSLT 1.0。

Answer 1

这种转变:

<xsl:stylesheet version="1.0"
 xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
 <xsl:output omit-xml-declaration="yes" indent="yes"/>
 <xsl:strip-space elements="*"/>

 <xsl:key name="kYear" match="year" use="."/>

 <xsl:key name="kEventByMonthYear" match="event"
  use="string(date)"/>

 <xsl:key name="kMonthByMonthYear" match="month"
  use="string(..)"/>

 <xsl:key name="kMonthByYear" match="month"
 use="../year"/>

 <xsl:template match="/*">
  <xsl:for-each select=
    "*/date/year
            [generate-id() = generate-id(key('kYear', .)[1])]
    ">
   <h2><xsl:value-of select="."/></h2>
   <dl>
      <xsl:apply-templates select=
      "key('kMonthByYear', current())
           [generate-id()
           =
            generate-id(key('kMonthByMonthYear',
                             string(..)
                         )[1]
                     )
            ]"/>
      </dl>
  </xsl:for-each>
 </xsl:template>

 <xsl:template match="month">
    <dt><xsl:value-of select="."/></dt>

    <xsl:for-each select=
    "key('kEventByMonthYear', string(current()/..))">
     <dd><xsl:value-of select="description"/></dd>
    </xsl:for-each>
 </xsl:template>
</xsl:stylesheet>

应用于以下 XML 文档时:

<events>
    <event>
        <date>
            <year>2012</year>
            <month>January</month>
        </date>
        <description>Jan1</description>
    </event>
    <event>
        <date>
            <year>2012</year>
            <month>January</month>
        </date>
        <description>Jan2</description>
    </event>
    <event>
        <date>
            <year>2012</year>
            <month>March</month>
        </date>
        <description>Mar1</description>
    </event>
    <event>
        <date>
            <year>2012</year>
            <month>March</month>
        </date>
        <description>Mar2</description>
    </event>
    <event>
        <date>
            <year>2012</year>
            <month>March</month>
        </date>
        <description>Mar3</description>
    </event>
    <event>
        <date>
            <year>2012</year>
            <month>July</month>
        </date>
        <description>Jul1</description>
    </event>
    <event>
        <date>
            <year>2012</year>
            <month>July</month>
        </date>
        <description>Jul2</description>
    </event>
    <event>
        <date>
            <year>2012</year>
            <month>September</month>
        </date>
        <description>Sep1</description>
    </event>
    <event>
        <date>
            <year>2012</year>
            <month>October</month>
        </date>
        <description>Oct1</description>
    </event>
    <event>
        <date>
            <year>2012</year>
            <month>October</month>
        </date>
        <description>Oct2</description>
    </event>
    <event>
        <date>
            <year>2012</year>
            <month>November</month>
        </date>
        <description>Nov1</description>
    </event>
    <event>
        <date>
            <year>2012</year>
            <month>November</month>
        </date>
        <description>Nov2</description>
    </event>
    <event>
        <date>
            <year>2012</year>
            <month>December</month>
        </date>
        <description>Dec1</description>
    </event>
    <event>
        <date>
            <year>2012</year>
            <month>December</month>
        </date>
        <description>Dec2</description>
    </event>
    <event>
        <date>
            <year>2012</year>
            <month>December</month>
        </date>
        <description>Dec3</description>
    </event>
    <event>
        <date>
            <year>2013</year>
            <month>January</month>
        </date>
        <description>Jan1</description>
    </event>
    <event>
        <date>
            <year>2013</year>
            <month>January</month>
        </date>
        <description>Jan2</description>
    </event>
</events>

产生想要的正确结果:

<h2>2012</h2>
<dl>
   <dt>January</dt>
   <dd>Jan1</dd>
   <dd>Jan2</dd>
   <dt>March</dt>
   <dd>Mar1</dd>
   <dd>Mar2</dd>
   <dd>Mar3</dd>
   <dt>July</dt>
   <dd>Jul1</dd>
   <dd>Jul2</dd>
   <dt>September</dt>
   <dd>Sep1</dd>
   <dt>October</dt>
   <dd>Oct1</dd>
   <dd>Oct2</dd>
   <dt>November</dt>
   <dd>Nov1</dd>
   <dd>Nov2</dd>
   <dt>December</dt>
   <dd>Dec1</dd>
   <dd>Dec2</dd>
   <dd>Dec3</dd>
</dl>
<h2>2013</h2>
<dl>
   <dt>January</dt>
   <dd>Jan1</dd>
   <dd>Jan2</dd>
</dl>

说明:

正确使用 Muenchian method for grouping -- 具有复合分组键。