How I wrote a self-hosting C compiler in 40 days

Honestly, the most difficult, time consuming, and mundane aspect to this project would have to be the parser, which was apparently written in C by hand. So bravo.

Getting to some of the final notes:

> ... I'd choose a different design than that if I were to write it again. Particularly, I'd use yacc instead of writing a parser by hand and introduce an intermediate language early on.

That's why I found the LALRPOP post by one of the Rust developers interesting. Writing your own parser generator is actually much easier than writing a parser by-hand (depending on the complexity of the language, here not that complex and still difficult), and I think it's more instructive than using a free or open parser-generator or compiler compiler. The downside is that it is less practical, because almost none of the important aspects of language implementation involve the parser.

This is completely contrary to my experience, in which parser generators have not paid for themselves. Writing a parser by hand in C is generally easier and less time-consuming over the long run than struggling along with a parser generator, especially if you have any interest in producing useful syntax error messages or recovering from other kinds of errors in some useful way.

I agree that almost none of the important aspects of language implementation involve the parser - and that's why I write 'em by hand! It doesn't take much time, and it's much easier to debug whatever problems you run into when you can use your ordinary debugging tools.