[laurencerowe]

As an experienced developer who did not do a compilers course at university I was able to write a SQL/JSONPath evaluator in TypeScript in a week or so. I don’t expect a minimal C compiler would be that much more complex.

Essentially all you need is a grammar, parser library and a couple of tree walkers to convert the AST first to expand macros and then convert to assembly.

A production compiler with all its optimisation steps is of course far more complex and more modern languages have many more features, but C is really pretty simple (the K&R book is concise and good!) as it was built to work on the computers of half a century ago.

[59nadir]

You don't need a parser library; writing the tokenizer + parsing logic isn't a very time consuming endeavor and the code doesn't suffer from it either. The upside is also that you're not taking on some monstrosity of a library for something you can implement in a tenth of the lines yourself. You'll also end up with something you actually fully understand yourself as well, which should be a big plus.

[laurencerowe]

While I suspect I would learn more writing a tokenizer and parsing logic myself I find grammars much easier to read and maintain.

ANTLR is pretty good and is supported across several languages and something I had previously used for some quick Elasticsearch query syntax munging in Python. It also means you can often start from an already existing grammar.

The JS version of ANTLR didn't seem to work for me so for the SQL/JSONPath stuff ended up using the Moo lever and Nearly parser which was rather pleasant. https://nearley.js.org

[marcodiego]

Using a library is cheating. Any one with enough knowledge can create their own programming language in two weekends using parser combinators.