Re: Muenchian method, and keys 'n stuff

Hi Dave,

> but I can't figure out a way of iterating over an alphabet, and
> processing the records to 'announce' the missing letters (i.e. no
> books beginning with that letter)

I'd just iterate over the alphabet held in a string, with a recursive
template. It starts off with the whole alphabet and gradually whittles
it down letter by letter until there's no alphabet left:

<xsl:template name="alphabetical">
  <xsl:param name="alphabet" select="'abcdefghijklmnopqrstuvwxyz'" />
  <xsl:if test="$alphabet != ''">
    <xsl:variable name="letter"
                  select="substring($alphabet, 1, 1)" />

    ... do things with the letter ...
    
    <xsl:call-template name="alphabetical">
      <xsl:with-param name="alphabet"
                      select="substring($alphabet, 2)" />
    </xsl:call-template>
  </xsl:if>
</xsl:template>

In your case, the thing you want to do with the letter is identify
those r elements whose Ra/lett is that letter. You can do this with
the key that you've made, as follows:

<xsl:template name="alphabetical">
  <xsl:param name="alphabet" select="'abcdefghijklmnopqrstuvwxyz'" />
  <xsl:if test="$alphabet != ''">
    <xsl:variable name="letter"
                  select="substring($alphabet, 1, 1)" />

    <xsl:variable name="auths"
                  select="key('auth', $letter)" />
    <xsl:choose>
      <xsl:when test="$auths">
        <h2>
          The letter
          <xsl:value-of select="translate($letter, $l, $u)" />
        </h2>
        <xsl:for-each select="$auths">
          <h3><xsl:value-of select="Ra/au" /></h3>
        </xsl:for-each>
      </xsl:when>
      <xsl:otherwise>
        <p>
          There are no authors beginning with
          <xsl:value-of select="$letter" />
        </p>
      </xsl:otherwise>
    </xsl:choose>
    
    <xsl:call-template name="alphabetical">
      <xsl:with-param name="alphabet"
                      select="substring($alphabet, 2)" />
    </xsl:call-template>
  </xsl:if>
</xsl:template>

To call the template, all you need is:

  <xsl:call-template name="alphabetical" />

Note that the key will give you all r elements with the same Ra/lett,
and as such it won't be scoped within the 'adventure'. To get the
scoping, you need to do one of the following:

  - include the adventure's (generated) ID within the key, and pass
    that ID to the alphabetical template
  - don't use the key to retrieve the rs with a particular Ra/lett,
    just use r[Ra/lett = $letter] instead (less efficient than a key,
    probably)

Cheers,

Jeni

---
Jeni Tennison
http://www.jenitennison.com/


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