Microsoft announced MGrammar as part of the highly anticipated Oslo SDK at PDC08. I have to say that MGrammar have the best grammar syntax I have ever worked with, and the GLR parser is reasonably good. The only thing that was missing was vim support so I had to do that my self. In the zip file bellow you will find a mg.vim syntax file, and a mg.vim compiler plugin.

Project: vim-mgrammar

Note: There are some bugs in the syntax when using folding, when I have some time I will update this post with a fixed syntax file.