I've found this book to be a good way to learn a new language, because it forces you to do a bit of reading about various language features and patterns to create equivalent implementations. For languages that lack some of the features in Java, it can be tricky to learn how to apply similar patterns, but that's half the fun (for me).

The two most popular discussions of this fantastic book:

2020 with 777 points: https://news.ycombinator.com/item?id=22788738

2024 with 607 points: https://news.ycombinator.com/item?id=40950235

In case anyone finds it useful, we (CodeCrafters) built a coding challenge as a companion to this book. The official repository for the book made this very easy to do since it has tests for each individual chapter.

Link: https://app.codecrafters.io/courses/interpreter/overview

Really I would love to know how parse context sensitive stuff like typedef which will have "switched" syntax for some tokens. Would like to know things like "hoisting" in C++, where you can you the class and struct after the code inside the function too, but I just find it hard to describe them in rigorous formal language and grammar.

Hacky solution for PEG such as adding a context stack requires careful management of the entry/exit point, but the more fundamental problem is that you still can't "switch" syntax, or you have to add all possible syntax combination depending on the numbers of such stacks. I believe persistent data structure and transactional data structure would help but I just couldn't find a formalism for that.

One of the best resources for learning compiler design. The web version being free is incredibly generous.