ruleStack = new RuleStack();
newGrammar();
firstNode = createGrammarNode("<sil>");
GrammarNode finalNode = createGrammarNode("<sil>");
finalNode.setFinalNode(true);
// go through each rule and create a network of GrammarNodes
// for each of them
for (Map.Entry<String, JSGFRule> entry : rules.entrySet()) {