putFunction(new DateAddFunction(), reservedFunctions);
putFunction(new DateDiffFunction(), reservedFunctions);
putFunction(new LengthFunction(), reservedFunctions);
putFunction(new SubStringFunction(), reservedFunctions);
putFunction(new ToLowerFunction(), reservedFunctions);
putFunction(new ToUpperFunction(), reservedFunctions);
}
FunctionExpression comp = new GenericFunctionExpression(simbol);