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Christian Lück edited this page Jan 5, 2022 · 1 revision

XSL Transformation for Updating the Header

Your TEI documents' headers may contain the same pieces of information again and again. Keeping all this redundant information up to date can be very tedious.

There is a transformation scenario called oXbytei :: update header for this purpose. It needs a prepared central header file like the one described below.

As an example, have a look at the following central header file. Note the @source attributes! @source="local" means, that the local version of the elment and its subtree is to be preserved. @source="local*" means that all siblings with the same element name from the local header are to be preserved.

<TEI xmlns="http://www.tei-c.org/ns/1.0" xml:lang="en">
   <teiHeader>
      <fileDesc>
         <titleStmt>
            <title source="local*">Central Header Document</title>
         </titleStmt>
         <publicationStmt>
            <p>Shipped as a sample with a framework</p>
         </publicationStmt>
         <sourceDesc source="local">
            <p>borne again</p>
         </sourceDesc>
      </fileDesc>
      <profileDesc>
         <langUsage>
            <language ident="de" xml:lang="de">deutsch</language>
            <language ident="fr" xml:lang="fr">français</language>
            <language ident="en">english</language>
         </langUsage>
      </profileDesc>
      <encodingDesc>
         <listPrefixDef>
            <prefixDef matchPattern="([a-zA-Z0-9_-]+)" replacementPattern="personography.xml#$1"
               ident="psn"/>
            <prefixDef matchPattern="([a-zA-Z0-9_-]+)" replacementPattern="geography.xml#$1"
               ident="place"/>
         </listPrefixDef>
      <xenoData/>
      <revisionDesc source="local">
         <change/>
      </revisionDesc>
      </encodingDesc>
   </teiHeader>
   <text>
      <body>
         <p>...</p>
      </body>
   </text>
</TEI>

And now think of this local TEI document, which's header needs an update:

<TEI xmlns="http://www.tei-c.org/ns/1.0">
  <teiHeader>
      <fileDesc>
         <titleStmt>
            <title>Stable</title>
            <title type="subtitle">Really stable</title>
            <author>me</author>
         </titleStmt>
         <publicationStmt>
            <p>Publication Information to be Updated</p>
         </publicationStmt>
         <sourceDesc>
            <listWit>
               <witness xml:id="A"/>
               <witness xml:id="B"/>
            </listWit>
         </sourceDesc>
      </fileDesc>
     <revisionDesc>
        <change who="me" when="2021-12-23">Anything done</change>
     </revisionDesc>
  </teiHeader>
  <text>
      <body>
         <p>Some text here.</p>
      </body>
  </text>
</TEI>

Merging the header from the central file into the local TEI document would result in this:

<TEI xmlns="http://www.tei-c.org/ns/1.0">
  <teiHeader>
      <fileDesc>
         <titleStmt>
            <title>Stable</title>
            <title type="subtitle">Really stable</title>
         </titleStmt>
         <publicationStmt>
            <p>Shipped as a sample with a framework</p>
         </publicationStmt>
         <sourceDesc>
            <listWit>
               <witness xml:id="A"/>
               <witness xml:id="B"/>
            </listWit>
         </sourceDesc>
      </fileDesc>
      <profileDesc>
         <langUsage>
            <language ident="de" xml:lang="de">deutsch</language>
            <language ident="fr" xml:lang="fr">français</language>
            <language ident="en">english</language>
         </langUsage>
      </profileDesc>
      <encodingDesc>
         <listPrefixDef>
            <prefixDef matchPattern="([a-zA-Z0-9_-]+)" replacementPattern="personography.xml#$1" ident="psn"/>
            <prefixDef matchPattern="([a-zA-Z0-9_-]+)" replacementPattern="geography.xml#$1" ident="plc"/>
            <prefixDef matchPattern="([a-zA-Z0-9_-]+)" replacementPattern="geography.xml#$1" ident="place"/>
         </listPrefixDef>
      </encodingDesc>
      <xenoData/>
      <revisionDesc>
        <change who="me" when="2021-12-23">Anything done</change>
     </revisionDesc>
   </teiHeader>
  <text>
      <body>
         <p>Some text here.</p>
      </body>
  </text>
</TEI>

Provided,

  • that you tag the elements which should be kept in the local file, and
  • that the header of the local file does not contain paths, which are not present,

it's possible to use a generic XSL transformation, for merging the non-tagged elements from the central file into the local document. You can even run this as a mass transformation on all your TEI documents (except the central header file).

So you can just keep the redundant information in a central file and are relieved from the burden to keep all the headers up to date.

How it works

The XSL script calculats XPath expressions like fileDesc[1]/titleStmt[1]/title[1] for accessing the corresponding element in the other file's header. With the starred tag local*, the trailing \[[0-9]+\]$ of this XPath is removed.

This said, it's clear why the following header tagging leads to a growing number of <title> elements in the local document:

<titleStmt>
	<title type="maintitle">Kritische Schriften</title>
	<title type="subtitle" source="local*">Kritik der Urteilskraft</title>
</titleStmt>

So, leave away the star.

TODO: Should there be more complex tagging added? Or should there be feature added to reproduce subtrees in the local document, for which are no corresponding elements in the central header?

TODO: Caculate a hash of the central header add put in into an attribute.

Further Notes

It would be possible to tag the elements in the local file, but then, we would have all these misused @source attributes in the documents that we want to ship to the outside world.

There are different approaches, to handle the redundancy: 1) linking the redundant pieces to locations in a project's central header file using XInclude, 2) transforming the header. The first approach has the downside of a compilation need before shipping the TEI documents to outside world. Moreover, it's only well suited for including biggers pieces. But including redundant smaller pieces soon gets as tedious as keeping them directly in the header.

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