proguard-assembler VS klox

Nice project! At Guardsquare, we have a similar project: https://github.com/Guardsquare/proguard-assembler

One of the things we use it for is testing: we can craft specific bytecode sequences that we want to test; for example, it's useful to test cases we've seen in the wild (e.g. obfuscated code) or to create a test that doesn't rely on a specific compiler/version.

An example of using the assembler from a ProGuard unit test https://github.com/Guardsquare/proguard/blob/master/base/src...

Last year I did the same: using my extended implementation of Lox. I didn't get so far in Advent of Code itself (only 4 days) since I spent much more time adding features to the language / standard library! Standard Lox as implemented in the Crafting Interpreters book is lacking many useful things including input reading, arrays, collections like sets & hash maps. Example: https://github.com/mrjameshamilton/klox/blob/master/examples/aoc-2021/advent-day01.lox

I was also experimenting in Kotlin with some higher-level helper functions for the ProGuardCORE code builder, like using code blocks for try-catch, switches etc

Something else that could make your code generation for your JVM language easier: ProGuardCORE (https://github.com/Guardsquare/proguard-core). It can be used to read, generate and analyse Java bytecode.

Some examples for code generation: ProGuard where the project originated (https://github.com/Guardsquare/proguard), Brainf*ck compiler (https://github.com/mrjameshamilton/bf), Lox compiler (https://github.com/mrjameshamilton/klox)

Disclaimer: I work at Guardsquare on ProGuardCORE so may be biased ;)

I implemented Lox in Kotlin based on the book's Java interpreter then added a JVM backend using ProGuardCORE: https://github.com/mrjameshamilton/klox

It's a great book! I really liked how it guides step-by-step, always having something working building up to the full interpreter for Lox. I haven't yet gotten around to the 2nd part of the book (the C based interpreter/vm) because I got carried away with adding extra features to my Kotlin Lox implementation (including a JVM backend)! https://github.com/mrjameshamilton/klox

Not a book or guide but a useful library for working with/generating JVM class files is ProGuardCORE. It's the underlying library used by ProGuard and I also recently used it to add a JVM backend to my implementation of Lox from the Crafting Interpreters book.

My implementation can be found here: https://github.com/mrjameshamilton/klox