]> >From reading the camlp5 documentation, I've managed to write a syntax extension that adds a new expression starting with a distinct keyword, and it seems to work fine. However, if I want to experiment with infix notations, things get a little trickier. I need to specify it's precedence and associativity, of course. So, there is a list of syntactic structures on this page: http://pauillac.inria.fr/~ddr/camlp5/doc/htmlc/ast_transi.html 1) Where can I find the "level names" for each of these syntactic constructs, for use with BEFORE, LIKE, etc? Is that what the "Comment" column is for? 2) I am confused by the fact that this is a list is for the revised syntax. I think most people (including me) want to modify the original syntax. e.g., imagine that I want to modify the record update operator "<-" in the original syntax---I need to refer to it somehow, but it doesn't even appear in the list. - Aaron