I absolutely love this article. When I was a young lad, must have been 20 I came across some programming books, including programming in Ada. I read so much o

I absolutely love this article. When I was a young lad, must have been 20 I came across some programming books, including programming in Ada. I read so much of it but never wrote a line of code in it, despite trying. Couldn't get the build environment to work. But the idea of contracts in that way seemed so logical. I didn't understand the difference this article underpins though. I learned Java and thought interfaces were the same. Great article, great language.