If you have a language that does TCO recursive descent parsers are fantastic to write. I wrote a JSON parser in guile scheme that was fast enough for My purpose

If you have a language that does TCO recursive descent parsers are fantastic to write. I wrote a JSON parser in guile scheme that was fast enough for My purposes in about 170 LOC. It was extremely simple. No state variables, each function was its own state. The only place where there was any call stack buildup was of course in nested arrays/hashes, but guile doesn't do stack overflows, just out of memory, so that was less of an issue.