Hello, I do not completely understand the first part of chapter 3 of the Haskell-report. Concretely I am stumbling about the notation of nonterminals indexed by their precedence level. This should be a number ranging from 0 to 9. But what about this exp^{10} production rule? I would be very appreciated if someone could explain this part in some more detail. I am trying to introduce a new language construct into this grammar and I want to insert it at the right place :-) Ciao, Steffen