Do you mean it crash visual studio or it just doesn't work with vs?

.mll files and .mly files don't work in visual studio you need to compile these files to .ml/.fs files using fslex and fsyacc, then import the resulting .ml files.

Unfortunatly you do have import the files in the right order. It's often easier just to import all files then edit the .fsproject file to reorder the file. It's just a text file and the format is easy to follow.

You may have to make a number of changes to get the code working F#, there are difference between fslex/fsyacc and ocamllex/ocamlyacc and indeed between F# and ocaml. The changes should relatively small and staight foward, but if you do have any problems we'll probably be able to help you here.

Cheers,
Rob