XSLT working properly in Postgres at last

Productive as ever, Tom Lane seems to have taken a break from making his head hurt on replication issues, and instead fixed some long-standing problems we've had with the xml2 contrib module's memory management. My small contribution was to get it building correctly on Windows.

This means (among other things) that we can now use xslt_process to transform XML in various useful ways. Examples could include generating HTML (or XHTML) from it, or preparing XSL-FO output as a step towards turning it into PDFs, or just pretty printing it. I've just spent a little time verifying that things that were previously broken now work.

Here for example is a simple XML pretty printer function (it can probably be improved on, but this will do for a demo):

create or replace function xml_pretty_print(input xml) 
    returns xml
    language sql as
$func$

select xslt_process($1::text,
$$<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" 
    version="1.0">
   <xsl:output method="xml" omit-xml-declaration="yes" indent="yes"/>
   <xsl:strip-space elements="*"/>
   <xsl:template match="@*|node()">
     <xsl:copy>
       <xsl:apply-templates select="@*|node()"/>
     </xsl:copy>
   </xsl:template>
 </xsl:stylesheet>
$$::text)::xml

$func$;

I have recently found myself doing a lot of XML for one reason or another, and the fact that Postgres just keeps getting better at it is good news.