MathML to LaTeX conversion

I'm trying to figure out how to convert a MathML representation of a math equation and convert it to the LaTeX representation of that math equation. So for example...

<math>
  <mrow>
   开发者_JAVA技巧 <mfrac>
      <mrow><mi>x</mi></mrow>
      <mrow><mi>y</mi></mrow>
    </mfrac>
  </mrow>
</math>

... is a simple stacked fraction and it's LaTeX representation would be...

\frac{x}{y}

I'm guaranteed that the MathML has no presentational markup because I am constructing the MathML string dynamically and I control how/where the MathML elements are inserted; the MathML string is just pure structure of the math equation.

So my question is, are there any Java/JavaScript libraries out there that can take a MathML input string, like the one above, and generate the corresponding LaTeX string? I would much rather not have to write this parser myself. If not Java/JavaScript, are any libraries at all that can do this?

If not, any suggestions on how to approach this problem of writing my own parser? Where to start, things to consider, resources, etc...?

UPDATE

Thanks to Optimal Cynic, I was able to use this Java library to do what I want. It is not perfect however, but I can easily modify it and make it work well. However, I would still like to see this done in JavaScript. So are there any tools like this written in JavaScript? If not, I'll resort to translating it myself.

Note: I am using MathJax to render the MathML on the page, but MathJax does not currently support a way to go from MathML to LaTeX. It can only go from LaTeX to MathML.

Try http://www.tilman.de/programme/mathparser/anleitung_en.html - it's written in Java and the source is available.

What's wrong with XSLT, SAX parsers, or DOM parsers?

Bindings for SAX and DOM parsers exist for all major languages (and pretty much every other language too). I would recommend DOM parsing using a functional language, but tastes differ.

XSLT is a functional language designed for processing XML.

I had similar problem and mathparser provided in url from question wasn't working for me at all.

I converted MathML to LaTeX by using XSLT MathML Library with Saxon-HE but since XSLT MathML library is pure XSLT any XSLT transformation tool should handle it. Output is not always perfect but it gave me better results than web-xslt mentioned somewhere at stackexchange network.

Command line usage with saxon:

saxon -o output.tex input.mml xsltml_2.1.2/mmltex.xsl