Peculiar RegEx Classes

While doing research for my post Unicode in Visual Studio.NET 2003 I came across a bunch of interesting classes in the System.Web.RegularExpressions assembly. These classes seem to be used quite extensively by the page parser which takes apart ASPX files. They search for tags, comments, server-side directives, etc.

You can find them in System.Web.RegularExpressions.dll. If you don't see it in your Reflector load the DLL from C:\WINDOWS\Microsoft.NET\Framework\v1.1.4322 or whatever the appropriate path is on your box.

Here's a rundown on the classes I'm talking about:

namespace System.Web.RegularExpressions
{
    public class AspCodeRegex : Regex {}
    public class AspExprRegex : Regex {}
    public class CommentRegex : Regex  {}
    public class DatabindExprRegex : Regex {}
    public class DataBindRegex : Regex {}
    public class DirectiveRegex : Regex {}
    public class EndTagRegex : Regex {}
    public class GTRegex : Regex {}
    public class IncludeRegex : Regex {}
    public class LTRegex : Regex {}
    public class RunatServerRegex : Regex {}
    public class ServerTagsRegex : Regex {}
    public class SimpleDirectiveRegex : Regex {}
    public class TagRegex : Regex {}
    public class TextRegex : Regex {}
}

Most class names are pretty self explanatory. If you're writing some kind of a parser, check out class constructors and reuse their RegEx expressions. Why reinvent the wheel, right?

Interestingly enough, each one of these classes uses a corresponding RegexRunnerFactory which is, ahem, "not intended to be used directly from your code." These factories handle heavy lifting of running searches. If you're really hardcore into it, I think you'll find these "runners" interesting.