A PEG grammar for SQL query languages. This codebase has been discussed and expalined in the article below. https://duckdb.org/2024/11/22/runtime-extensible-parsers.html#:~:text=Parsing%20Expression%20Grammar&text=PEG%20parsers%20are%20top%2Ddown,dependent%20amount%20of%20extra%20memory.