Came up with the idea

A recruiter asked me how well I know C#. I didn't have a straight answer. I used it from its first release, but how many lines of it did I write in the last couple years? What is my breadth and depth of knowledge of C#/.Net? Can it be quantified?
I built a simple tool that analyzed my past C# projects to give me some metrics. It made me realize that those numbers are more accurate than vague self-assessments in outdated resumes.