Is there an [XSLT](http://www.w3.org/TR/xslt) equivalent for JSON? Something to allow me to do transformations on JSON like XSLT does to XML.
['https://Stackoverflow.com/questions/1618038', 'https://Stackoverflow.com', 'https://Stackoverflow.com/users/147141/']
To say lack of tools suggest lack of need is just begging the question. The same could be applied to support for X or Y in Linux (Why bother developing quality drivers and/or games for such a minority OS? And why pay attention to an OS that big game and hardware companies don't develop for?). Probably the people who would need to use XSLT and JSON end up using a somewhat trivial workaround: Transforming JSON into XML. But that's not the optimal solution, is it?

When you have a native JSON format and you want to edit it "wysywyg" in the browser, XSLT would be a more than adequate solution for the problem. Doing that with traditional javascript programming can become a pain in the arse.

In fact, I have implemented a "stone-age" approach to XSLT, using substring parsing to interpret some basic commands for javascript, like calling a template, process children, etc. Certainly implementing a transformation engine with a JSON object is much easier than implementing a full-fledged XML parser to parse the XSLT. Problem is, that to use XML templates to transform a JSON object you need to parse the XML of the templates.

To tranform a JSON object with XML (or HTML, or text or whatever) you need to think carefully about the syntax and what special characters you need to use to identify the transformation commands. Otherwise you'll end up having to design a parser for your own custom templating language. Having walked through that path, I can tell you that it's not pretty.

Update (Nov 12, 2010): After a couple of weeks working on my parser, I've been able to optimize it. Templates are parsed beforehand and commands are stored as JSON objects. Transformation rules are also JSON objects, while the template code is a mix of HTML and a homebrew syntax similar to shell code. I've been able to transform a complex JSON document into HTML to make a document editor. The code is around 1K lines for the editor (it's for a private project so I can't share it) and around 990 lines for the JSON transformation code (includes iteration commands, simple comparisons, template calling, variable saving and evaluation). I plan to release it under a MIT license. Drop me a mail if you want to get involved.
For a working doodle/proof of concept of an approach to utilize pure JavaScript along with the familiar and declarative pattern behind XSLT's matching expressions and recursive templates, see <https://gist.github.com/brettz9/0e661b3093764f496e36>

(A similar approach might be taken for JSON.)

Note that the demo also relies on JavaScript 1.8 expression closures for convenience in expressing templates in Firefox (at least until the ES6 short form for methods may be implemented).

Disclaimer: This is my own code.