[xml] XSLT question

[Colin Fox <cfox cfconsulting ca>]

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I've got a question about XSLT and libxslt.

Assuming an XML file that looks like this:

<schema generated='yes'>
    <table name='people' schema='public'>
    ...
    </table>

    <table name='accounts' schema='financial'>
    ...
    </table>
    ...
</schema>

We have tables under 'schema', and each table has an attribute called
'schema' (unfortunate names, but not my choice).

What I need to do is to compile a unique list of nodes that are
comprised of the schema attributes.

In SQL, it would be:

select distinct (schema) from  table;

I need it as a node list so that I can use xsl:for-each and iterate
through the list.

I'm currently working with the key() function, and I have the key
definition and the invocation.

The defintion is:
<xsl:key name='schemas_key' match='table' use='@schema' />

The usage is:
    <xsl:variable name="schemas_var">
    <xsl:for-each
select="table/@schema[generate-id(.)=generate-id(key('schemas_key',.)[1])]">
        <xsl:sort select="." />
        <xsl:copy-of select="." />
    </xsl:for-each>
    </xsl:variable>

This doesn't seem to work, and also, I get this message as the first
line of output:

xsltApplyOneTemplate: key was not compiled


Can anyone suggest an example for getting a unique or distinct list of
values for a particular attribute? What I have here is the best I've
been able to come up with so far by going through my books.

Thanks,
  cf

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