Antlr the last I looked and tried to use it was a pain. Version mismatches and incompatible changes... Plain old bison/yacc/lex or some of the newer Rust parsing libraries would probably be simpler and easier to maintain.
Yeah dvc94ch who wrote most of what's been done for v2 so far was suggesting Rust and then web-assembly. Kind of warming to it after using Antlr for a while. We both really need JS versions though so I am still not sold. Compiling with Emscripten might be an option but it could be a lot of pain as well.
I’ve just tinkered with wasm and rust, but it was surprisingly pretty straightforward. It seems there a huge amount of effort being placed in the ecosystem. Great project so far! I’ll have to check out the bom tools.
But if I'd like to support older browsers I am out of luck, no?
Emscripten compiles to asm.js, which is just a subset of JS. CanIUse will tell you some browsers don't support it, but it really means they don't support accelerating it. Your code very well may still run in those browsers (but I'm not sure about the determinant of those cases).