Why does XSLT seem to irritate so many people?

Question

What it is about XSLT that people find irritating? Is it the syntax (which is pretty unusual) or just the way XSLT works in general? Are there features that are lacking?

I did a little bit of XSLT (around 800 lines) a while ago and found it not that bad. So why the general animosity against it?

Answer 1

I think people find it difficult to get their heads around XSLT (and bitch about it) because it is functional and declarative in nature, unlike c# or java programming. Navigating around documents can end up being complicated when XPATH statements get clever - though this is a feature of XPATH rather than XSLT. XPATH typically gets complex when you don't know at design time the exact structure of a document so you start querying siblings, descendents and ancestors. This is when people inheriting a complex XSLT start considering career changes!

With XSLT it is very much 'right tool for the right job'. It is designed to transform an xml document into another xml document extremely quickly and efficiently. XSLT is almost certainly the best tool to use for this purpose because of its extensibility, the fact that it has been written for this purpose, widespread support for it in xml processors across the board, and in case i didnt mention it already, performance. Common use-cases:

1. converting an xml document purely containing data into a document exposing a user-interface such as an xhtml document
2. converting an xml document into a different structure to suit someone elses schema e.g. Biz2Biz communications

A great implementation of the xslt technology is the apache-cocoon project which transforms xml documents into multiple output formats including html, excel, chart images, pdf's with an extensible plugin architecture. We use it a lot for our reporting platform and it works very well. When developers start with it, they find the same familiar issues. Once they get over them, they would typically be writing what i am here.

I once worked with a guy who didnt want to work with (and learn) XSLT and ended up presenting a demo to the client which took over 20 seconds to render a page. When i finally persuaded him to use an XSLT transform instead of his dumb DOM code it took under a second.