else if (!contains(startsymbol))
violations.addViolation("Start symbol \""+startsymbol+"\""+
"is not defined through a production", location);
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();