if (getProductionCount() <= 0)
violations.addViolation("No productions are defined", location);
for (Enumeration e = productions.elements(); e.hasMoreElements() ;)
violations.addViolations(((Production)e.nextElement()).validate());
SymbolSet ntsymbols = getSymbols().getNonterminals();
for (int i = 0; i < ntsymbols.getSymbolCount(); i++)
if (!contains(ntsymbols.getSymbol(i)))
violations.addViolation("Nonterminal symbol \"" + ntsymbols.getSymbol(i) + "\"" +