> Also how vertical is the "vertical" approach really? It can be quite vertical, really. Like starting with a compiler for a language where the only correct pr

> Also how vertical is the "vertical" approach really? It can be quite vertical, really. Like starting with a compiler for a language where the only correct programs consists of a single integer. This is what I do with my students to get them started on their compiler project. Of course you may have to rethink and rewrite or adapt some code depending of the order in which you're adding features and how they interact, but that will be true anyway if your language evolve :).