Hacker News new | ask | show | jobs
by pan69 47 days ago
I learned to do this about 2 years ago (pre LLM). I have been developing software for ~30 years and somehow doing something like this was a major mental obstacle, mostly created by the perception of "the dragon book", as in this topic being full of mystical unobtainable incantations, so I never even dared venture into this space. Silly, I know. However, after diving into this and learning to write a recursive descent parser for a DSL I wanted to write, it felt like I'd acquired a superpower. Totally understand that there is many more layers to all of this, layer that can get very complex, but just learning that first bit...
1 comments

I wish people would start with Nystrom's https://www.craftinginterpreters.com/ and avoid the dragon etc unless they really, really need it. Almost everything I have learnt about compiler/vm development, I have done so by reading random blogs and articles on various aspects and small tutorials on writing parsers and vms.

Even stuff like Crenshaw's Let's Build a Compiler was more useful to me than all these books that do lexical analysis using regular expressions. I have written lexers and parsers hundreds of times for all kinds of DSLs and config languages and not once have I used regular expressions to scan the text.

Isn't using regex in this space kinda shunned, when you can easily write a grammar and parse things more reliably that way? Surprised to read that any books do that.
Every single book starts with regexes and DFA/NFA for lexical analysis. Too much ceremony for something you can write in 30 minutes and 300 lines