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();