private ITree GenerateAst(string p_strCplCode)
{
ErrorTracker ertErrors = new ErrorTracker();
AntlrParserBase cpbParser = ParserFactory.CreateParser(p_strCplCode, ertErrors);
ITree astCPL = cpbParser.Parse();
if (ertErrors.HasErrors)
throw new ArgumentException("Invalid CPL:" + Environment.NewLine + ertErrors.ToString(), "p_strCplCode");
return astCPL;
}