Went through the process (with help from MH) of building a simple index using the Lucene text search engine for the FrancoToile rebuild:

<?xml version="1.0" encoding="UTF-8"?>
<collection xmlns="http://exist-db.org/collection-config/1.0" xmlns:tei="http://www.tei-c.org/ns/1.0">
    <index>
        <lucene>
            <analyzer class="org.apache.lucene.analysis.standard.StandardAnalyzer"/>
            <analyzer id="ws" class="org.apache.lucene.analysis.WhitespaceAnalyzer"/>
            <text qname="tei:body" analyzer="ws">
                <ignore qname="tei:note"/>
            </text>
        </lucene>
    </index>
</collection>

The important notes are:

• You need to declare the namespaces you use in your documents in the <collection> element (e.g. xmlns:tei above)
• Use the full element names with namespaces when adding the indexes (e.g. tei:body)

Used these Exist docs as guides:

• http://demo.exist-db.org/exist/kwic.xml
• http://demo.exist-db.org/exist/lucene.xml