Unparser: real life lessons migrating Ruby tools from Parser to Prism—Martian Chronicles, Evil Martians’ team blog

Ruby 3.4 ships with Prism, a new built-in parser that’s faster, more portable, and designed to be the foundation for the coming generations of Ruby tooling. This shift affects everything that works with Ruby’s syntax: linters, formatters, IDEs, analyzers, and more. We’ll explore some weird Ruby, what Prism brings to the Ruby ecosystem, then use Unparser to show what the transition from Parser to Prism looks like in practice. The good news: the transition is doable. The catch: navigating API differences, new AST shapes, plenty of edge-case syntax, and testing thoroughly! .