Completely agree on your last point. I have written a compiler for a small subset of something like Pascal for the JVM and it was among all other things a big e

Completely agree on your last point. I have written a compiler for a small subset of something like Pascal for the JVM and it was among all other things a big exercise in software engineering. E.g. several times almost all the structure of my code became obsolete because a change in grammar or a need of doing different passes through the code / parse tree was required for a new feature in the language to work and that completely changed how everything else needed to work.