Six Feet Up: How to use XSLT in Diazo

What is XSLT?

It stands for 'eXtensible Stylesheet Language Transformations'. It is how Diazo works behind the scenes - all rules you write are actually translated to XSLT.

Why is XSLT needed?

It may not be needed at all, depending on how complex the selectors need to be in your Diazo rules. If you need to do anything involving loops or if statements, you'll need some XSLT.

Examples

<replace css:theme-children=".mainNav">
 <xsl:for-each css:select="#portal-globalnav > li">
   <li class="divider"></li>
   <xsl:apply-templates css:select="li.plain, li.selected"/>
 </xsl:for-each>
 <li class="divider"></li>
</replace>

This grabs each list item from Plone, and inserts a list item as a divider between each one. Note that the css: prefix can also be added to the XSLT within Diazo rules to use CSS style selectors.

<xsl:for-each css:select="#portal-personaltools a">
 <li>
   <xsl:copy-of select="current()"/>
 </li>
</xsl:for-each>

This pulls all links from the user dropdown and puts them into a list, instead of having them in a definition list.

Warnings

• XSLT has a steep learning curve. Make sure you have plenty of time and patience before tackling XSLT on your own.
• XSLT errors aren't very helpful. I don't have any good advice to help with this, except to maybe leave any expensive, breakable things out of your reach.

More examples and resources

I hope this gives you a brief understanding of how to utilize XSLT in your Diazo theme. You can find more examples and resources at:

• http://docs.diazo.org/en/latest/recipes/index.html
• http://www.w3schools.com/xsl/xsl_w3celementref.asp

Like what you've read? You can see more trainings like this one at sixfeetup.com/plone-cms/plone-how-to. Also, be sure to sign up for our weekly Plone & Python How-To digests.