Over in the SitePoint Forums, there's a new posting by phpPatterns.com's Harry Fuecks about something that Manuel Lemos has integrated with the PEAR classes - for Metabase.

Here's a sample reply: At first glance, the whole idea seems kind of pointless. Why in the world would you want to create an XML file that would be converted to PHP when you *built* it.
But, after thinking about it for a while, this could really revolutionize the way we think of programming. I mean, the whole argument about which language is better would go away because if you didn't like a particular language, just "convert" it to MetaL and then "convert" it to your own language. The only thing that I see is that using MetaL will reduce the flexibility of your code. If this is actually the case or not, I don't know. That takes more research then my lunchbreak allows.

This meta-language could really change the face of things if done correctly. There are a few issues mentioned in the thread, but overall, it seems quite positive...what do you think?