Evan Lenz

I have a project where I need to generate file names that are GUIDs. I’m using Saxon.NET. With the help of Google, I figured out how to do that, but it wasn’t immediately obvious. Hopefully this post will make the solution easier to find for other people trying to solve the same problem.

This is just one example of a .NET function you can access as an extension function in XSLT 2.0, so a more general-purpose treatment of .NET extension functions might be more useful. (I defer to “Writing extension functions for .NET” for that.) But if you’re like me, you spend most of your coding time within the safe, comfy confines of pure XSLT. And you do very little .NET development. So to ensure your continued comfort, here’s how you can generate a GUID in Saxon.NET (relevant parts highlighted):

<xsl:stylesheet version="2.0"
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
  xmlns:guid="clitype:System.Guid?partialname=mscorlib"
  exclude-result-prefixes="guid">

  <xsl:output indent="yes"/>

  <xsl:template match="/">
    <guids>
      <guid>
        <xsl:value-of select="guid:NewGuid()"/>
      </guid>
      <guid>
        <xsl:value-of select="guid:NewGuid()"/>
      </guid>
      <guid>
        <xsl:value-of select="guid:NewGuid()"/>
      </guid>
    </guids>
  </xsl:template>

</xsl:stylesheet>

Here’s an example result from applying this stylesheet (to any input document):

<guids>
   <guid>6dbd3a72-ad74-429d-97ca-3056e8940813</guid>
   <guid>cea97da4-9de5-4fb5-a35e-ba04a0dee906</guid>
   <guid>41c89105-6cf7-4fd6-b17a-ed04235a4804</guid>
</guids>

All you do is call the .NET platform’s System.Guid.NewGuid() method as an extension function. The function’s namespace URI identifies for Saxon what assembly and object class you’re interested in (System.Guid in this case).

Thanks to M. David Peterson: I found this usage buried in a code example in his lucidly-titled blog post: if ((OOP + FP + AOP) == XSLT 2.0) then ‘Composable Language’ else ‘Try Again’.

Short blog post, in bullet points:

• I’m attending SXSW Interactive very soon. PianoNinja was accepted as a semi-finalist in the ScreenBurn Game Design Competition! If my presentation is selected as a finalist, I’ll get to present a live 5-minute pitch for the judges.
• I’m working on a reference implementation for Inline XBRL. I had responded to their RFP for XSLT style sheet for extracting XBRL 2.1 from HTML documents with embedded Inline XBRL, and they chose my proposal. They’ve been very pleasant to work with, and the work is coming right along.
• I’m also working on a really cool SVG and XSL-FO project, generating SVG-based flow-chart diagrams.
• I’ve started Twittering. This may give me more excuses not to blog. So follow me! Disclaimer: we’ll see how long it lasts.

That’s all for now. See you again in 6 months. 🙂