public static FunctionExpression getReservedFunctions(String simbol) {
if (reservedFunctions == null) {
reservedFunctions = new TreeMap();
putFunction(new AndFunction(), reservedFunctions);
putFunction(new BetweenFunction(), reservedFunctions);
putFunction(new ContainsFunction(), reservedFunctions);
putFunction(new EndsWithFunction(), reservedFunctions);
putFunction(new EqualsFunction(), reservedFunctions);
putFunction(new GreaterEqThanFunction(), reservedFunctions);
putFunction(new GreaterThanFunction(), reservedFunctions);