Look at this code which prints out an HTML tag: https://github.com/yawaramin/dream-html/blob/main/lib/dream_html.ml#L39 https://github.com/yawaramin/dream-html/

Look at this code which prints out an HTML tag: https://github.com/yawaramin/dream-html/blob/main/lib/dream_html.ml#L39 https://github.com/yawaramin/dream-html/blob/main/lib/dream_... Initially you might think generating HTML tags from data structures in code should be a simple matter. But there are complexities--some tags are defined as having no child tags, others do. Some tags are purely character data (unstructured text), not structured data. Some are just comments. We need a way to compose multiple tags together into a single 'virtual' tag for flexible HTML generation. All these conditions can be pretty hard to keep track of--unless your compiler does exhaustiveness checking. Then the compiler will tell you if you missed any cases. In the example above I didn't make any manual effort to cover all the cases, I simple listed out the cases I wanted to handle in order. The compiler made sure that I didn't miss any.