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.
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