Nothing better than Rust and LALRPOP. I've been trying to play with Bison and C++ for the whole quarantine and nothing would compile. I just sat for two days with Rust and LALRPOP and I was able to make a small interpreter that can make new variables, calculate simple expressions and print stuff. Like this:

var = 5 + 3;
print var;
var = 2 * var + 4;
var2 = 3 * var + 3 * (var + 4);
print var2 * var;

And all this in just two days. I have no Rust experience except for toying with it on an online playground. I have no LALRPOP nor parsing experience. Two days.

Now, it's not like I wouldn't be able to do this in C++ too if somebody told me how to. But nobody has. And the documentation online is gruesome. None of the bison example I found online could compile. This is why documentation matters people! Honestly, if there's one reason I think old projects die, it's because they ether don't update themselves OR they don't update their documentations. Look at the US government now, looking for COBOL programmers.