>>===== MODE =====>>
citation
<<===== MODE =====<<


This test supports a proposal for extending CSL's conditional attributes.
The proposal introduces two new nodes and associated schema adjustments:

  * A cs:conditions element, as an optional first child of cs:if or cs:else-if,
    with a sole match attribute. When cs:conditions is used, its parent (cs:if 
    or cs:else-if) must have no attributes. Only cs:condition elements are permitted
    as children of cs:condition, and there must be at least one such child. 

  * A cs:condition element, with the same attributes as cs:if or cs:else-if.

The proposal also introduces a new value "nand" for the match attribute.

Under the proposal, conditional evaluation would take place as
follows:

  (1) cs:if and cs:else-if elements with attributes process exactly as under the
      current schema and specification.

  (2) cs:if and cs:else-if element with no attributes apply the conditions
      provided by the immediate cs:conditions child and its cs:condition
      children. The cs:condition children are evaluated first, according
      to the same logic as cs:if and cs:else-if. The results are then
      combined according to the match element on cs:conditions, returning
      a single boolean result for the parent cs:fi or cs:else-if element.

This change makes it possible to reduce the bulk of CSL code. As one example,
the construct below is found in several styles in the CSL repository:

    <macro name="year-date">
      <choose>
        <if type="webpage">
          <choose>
            <if variable="issued">
              <date variable="issued">
                <date-part name="year"/>
              </date>
            </if>
            <else>
              <date variable="accessed">
                <date-part name="year"/>
              </date>
            </else>
          </choose>
        </if>
        <else>
          <date variable="issued">
            <date-part name="year"/>
          </date>
        </else>
      </choose>
    </macro>

What the code does is to print the "accessed" date if the item is a
webpage and has no "issued" date, and otherwise to print the "issued"
date, regardless of item type. A nested cs:choose statement is needed,
because negative and positive conditions cannot be declared together
on the same cs:if or cs:else-if element.

With the proposed syntax, the code sample above can be rewritten as a
single cs:choose statement:

    <macro name="year-date">
      <choose>
        <if>
          <conditions match="all">
            <condition type="webpage" match="all"/>
            <condition variable="issued" match="none"/>
          </conditions>
          <date variable="accessed">
            <date-part name="year"/>
          </date>
        </if>
        <else>
          <date variable="issued">
            <date-part name="year"/>
          </date>
        </else>
      </choose>
    </macro>

>>===== RESULT =====>>
Item One is not an ARTICLE-JOURNAL, and has an EDITION
Item Two is a BOOK, but has no EDITION
Item Three is a CHAPTER, and has an AUTHOR
Item Four is an ARTICLE-JOURNAL with both VOLUME and ISSUE, but one of them is non-numeric
Item Five is an ARTICLE-JOURNAL with both VOLUME and ISSUE, and both of them are numeric
<<===== RESULT =====<<


>>===== CSL =====>>
<style 
      xmlns="http://purl.org/net/xbiblio/csl"
      class="note"
      version="1.1mlz1">
  <info>
    <title>Test fixture</title>
    <id>http://citationstyles.org/tests/fixture</id>
    <link href="http://citationstyles.org/tests/fixture" rel="self"/>
    <link href="http://citationstyles.org/documentation/text" rel="documentation"/>
    <category citation-format="author-date"/>
    <updated>2014-04-30T13:19:38+00:00</updated>
    <rights license="http://creativecommons.org/licenses/by-sa/3.0/">This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 License</rights>
  </info>
  <citation>
    <layout delimiter="&#x0A;">
      <group delimiter=" ">
        <text variable="title"/>
          <choose>
            <if>
              <conditions match="all">
                <condition type="article-journal" variable="volume issue" match="all"/>
                <condition variable="volume issue" match="all"/>
                <condition is-numeric="volume issue" match="nand"/>
              </conditions>
              <text value="is an ARTICLE-JOURNAL with both VOLUME and ISSUE, but one of them is non-numeric"/>
            </if>
            <else-if match="all" type="article-journal" variable="volume issue" is-numeric="volume issue">
              <text value="is an ARTICLE-JOURNAL with both VOLUME and ISSUE, and both of them are numeric"/>
            </else-if>
            <else-if>
              <conditions match="all">
                <condition type="article-journal" match="none"/>
                <condition variable="edition" match="all"/>
              </conditions>
              <text value="is not an ARTICLE-JOURNAL, and has an EDITION"/>
            </else-if>
            <else-if>
              <conditions match="all">
                <condition type="book"/>
                <condition variable="edition" match="none"/>
              </conditions>
              <text value="is a BOOK, but has no EDITION"/>
            </else-if>
            <else-if type="chapter" variable="author" match="all">
              <text value="is a CHAPTER, and has an AUTHOR"/>
            </else-if>
          </choose>
      </group>
    </layout>
  </citation>
</style>
<<===== CSL =====<<


>>===== INPUT =====>>
[
    {
        "edition": "5", 
        "id": "ITEM-1", 
        "title": "Item One", 
        "type": "book"
    }, 
    {
        "id": "ITEM-2", 
        "title": "Item Two", 
        "type": "book"
    }, 
    {
        "author": [
            {
                "family": "Snoapes", 
                "given": "John"
            }
        ], 
        "id": "ITEM-3", 
        "title": "Item Three", 
        "type": "chapter"
    }, 
    {
        "id": "ITEM-4", 
        "issue": "1", 
        "title": "Item Four", 
        "type": "article-journal", 
        "volume": "Supplement"
    }, 
    {
        "id": "ITEM-5", 
        "issue": "4", 
        "title": "Item Five", 
        "type": "article-journal", 
        "volume": "2"
    }
]
<<===== INPUT =====<<