“In the 25 years that the parser has existed, only 65 people have contributed to it, and only 13 of those have contributed more than 10 commits.”
CRuby parses every Ruby program through a 14,000-line parse.y file with no real documentation. Nine people touched it last year and two of them did any real work. Shopify spent a year writing YARP to replace it, and it now parses Shopify’s codebase, GitHub’s, CRuby and the top 100 gems. Shopify and GitHub run on a parser with a bus factor of two.