(.NET) Incorrect behaviour of NEsper with regex

Oleksii Mandrychenko added a comment - 12/Jan/12 11:25 AM I was debugging this issue for some time now and found that NEsper incorrectly handles WHERE regexp '' statement. So if I have SELECT * FROM MyType WHERE PropertyA regexp 'some valid regexp' Then NEsper does some string formatting and validation with 'some valid regexp' and removes some important (and valid) symbols from regexp. Proposed changes. (I don't really know the code but I tried to fix this small issue for me, this is not necessarily the best approach): ------- 1. com.espertech.esper.epl.expression.ExprRegexpNode public object Evaluate(EventBean[] eventsPerStream, bool isNewData, ExprEvaluatorContext exprEvaluatorContext) {...} Two occurances of _pattern = new Regex(String.Format("^{0}$", patternText)); change to _pattern = new Regex(patternText); Reason: I think it is up to the user how regexp is constructed, this shall not be part of a framework. ------- 2. com.espertech.esper.epl.parse.ASTConstantHelper public static Object Parse(ITree node){...} From case EsperEPL2GrammarParser.STRING_TYPE: { return StringValue.ParseString(node.Text, requireUnescape); } To case EsperEPL2GrammarParser.STRING_TYPE: { bool requireUnescape = true; if (node.Parent != null) { if (!String.IsNullOrEmpty(node.Parent.Text)) { if (node.Parent.Text == "regexp") { requireUnescape = false; } } } return StringValue.ParseString(node.Text, requireUnescape); } Reason: requireUnescape for all strings, but skip regexp as this brakes valid regexp and removes some valid symbols from it. ------- 3. com.espertech.esper.type.StringValue public static String ParseString(String value) {...} From public static String ParseString(String value) { if ((value.StartsWith("\"")) & (value.EndsWith("\"")) || (value.StartsWith("'")) & (value.EndsWith("'"))) { if (value.Length > 1) { if (value.IndexOf(' ') != -1) { return Unescape(value.Substring(1, value.Length - 2)); } return value.Substring(1, value.Length - 2); } } throw new ArgumentException("String value of '" + value + "' cannot be parsed"); } To public static String ParseString(String value, bool requireUnescape = true) { if ((value.StartsWith("\"")) & (value.EndsWith("\"")) || (value.StartsWith("'")) & (value.EndsWith("'"))) { if (value.Length > 1) { if (requireUnescape) { if (value.IndexOf(' ') != -1) { return Unescape(value.Substring(1, value.Length - 2)); } } return value.Substring(1, value.Length - 2); } } throw new ArgumentException("String value of '" + value + "' cannot be parsed"); } Reason: unescape all strings, but the regexp value.