public Rule newRule(NonTerminal head, Symbol... symbols) {
try {
if (head.getGrammar() != this) {
throw new IllegalArgumentException();
}
for (Symbol s : symbols) {
if (s.getGrammar() != this) {
throw new IllegalArgumentException();
}
}
Rule result = new Rule(this, head, symbols);
myRules.add(result);
head.addRule(result);
return result;
} finally {
invalidateGrammarData();
}
}
