Getting an unknown number of regex elements

Question

I have an string that may have several combinations of ANDs and ORs as follow:

   string display = "every ((Id2=Event(MachineInfo='M3',UserInfo='U3')) or (Id1=Event(MachineInfo='M2',UserInfo='U2')) and (Id0=Event(MachineInfo='M1',UserInfo='U1')))"

Right now I have an inefficient way to catch just the first MachineInfo and UserInfo but I don't know how to get the rest of the elements of the string:

 const string machineinfo = @"MachineInfo='(?<MachineInfo>[^']+)";
 const string userinfo = @"UserInfo='(?<UserInfo>[^']+)";

 string machineName = display.Contains("MachineInfo") ?
             Regex.Matches(display, machineinfo)[0].Groups[1].Value : "ANY";
 string userName = display.Contains("UserInfo") ?
             Regex.Matches(display, userinfo)[0].Groups[1].Value : "ANY";

What can I do to get all the MachineInfos and UserInfos without knowing the number of ANDs and ORs that I may have in display string??

score 1 · Answer 1 · answered Dec 14 '11 at 12:57

1

It looks like your syntax includes nesting with parenthesis. I suggest you don't use regexes to parse this, but instead look into using a proper parser. Regular expressions can't really express this nestedness.

answered Dec 14 '11 at 12:57

Daren Thomas

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Do you have any idea of which one? – Manolete Dec 14 '11 at 13:04
I guess ANTLR, but I don't know it well enough to recommend it. hang in there for a while and see what else pops up. – Daren Thomas Dec 14 '11 at 13:16
parboiled seems to be for Java, I am using C# – Manolete Dec 14 '11 at 13:36
I don't like very much the option of using external tools, I am more for a programmatic way to do it. – Manolete Dec 14 '11 at 14:22

score -1 · Answer 2 · answered Dec 14 '11 at 14:08

-1

Here is an inefficient/incomplete solution, try yourself to improve the result

        MatchCollection aa = Regex.Matches(display, machineinfo);
        foreach (var aaa in aa) {
            //aaa.ToString() 
            //try some thing with object aaa
        }

in the above code, object aaa will give you MachineInfo..try similar with UserInfo also and put ? operator inside foreach loop and try your skill..

answered Dec 14 '11 at 14:08

techBeginner

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@Manolete: why do you think so? – techBeginner Dec 14 '11 at 17:02

Getting an unknown number of regex elements

2 Answers2