title: spotting an Ambiguous BNF
body: <p>I have an assignment to correct an ambiguous BNF, but I am completely lost. I know this not a true programming question, and I will gladly delete it if it is not an appropriate question for these boards. Are there any good sites where I could learn more about BNF's? The one I am dealing with seems rather simple, but I can't find any examples or good explanations regarding BNF's. I have had some experience spotting ambiguous parse trees and other sorts of grammars, but I am completely lost on this one.</p>
  
  <p>Since it is a school assignment, I am not sure I should post the BNF in question, but if anyone knows of a good site that I could look over to perhaps gain a better understanding of how to attack my question. I really just don't know where to start.</p>