Source Code Generators

This page will look at how source code generators can impact regular expressions.

Source Code Generators and Regular Expressions

Since .NET 7 we have the possibility to use source code generators for regular expressions. The advantage over the regular approach is that we can get the same performance as new Regex("...", RegexOptions.Compiled) and the startup benefit of Regex.CompileToAssembly, but without the complexity of CompileToAssembly. As the code is generated it can be viewed and debugged.

So instead of this code:

private static readonly Regex HelloOrWorldCompiled =
        new("Hello|World", RegexOptions.Compiled | RegexOptions.IgnoreCase | RegexOptions.CultureInvariant);

We can write it like this:

[GeneratedRegex("Hello|World", RegexOptions.IgnoreCase | RegexOptions.CultureInvariant)]
private static partial Regex HelloOrWorldGenerator();