@roadriverrail As far as yacc and friends, in retrospect I'm really surprised how little those class of tools (basically none) I saw in the shops where I worked. I learned it basically on my own time, and by the time I did I wasn't in a position to advocate for a major rewrite.
To be fair, I think I heard once that available tools were weaker at handling anomalous or malicious inputs, which makes sense, but my drive is to build better tools, and it's so wild to me that we just... didn't.