Extending Ruby LSP with Prism | Janko Marohnić

Ruby LSP is a wonderful language server built on top of Prism, Rubydex and RBS. It implements a variety of features that enrich the code editing experience in Ruby projects. Its add-on architecture allows extending it with Rails features, Rubocop support and custom functionality. Coming from Vim, I was really used to rails.vim. When I switched to Zed, I started using Ruby LSP. In some ways I felt like I’d gained superpowers, as now I had all these modern editor features that are possible because my Ruby code is actually being parsed. On the other hand, I found there were some features I was missing. One such feature was following render calls in view templates. Rails.vim offered a gf (“go to file”) mapping, which when hovering over a render call would take me to the partial being rendered. In LSP terminology this functionality is called “go to definition”. If I were to implement it, I knew it had to live in the Rails add-on.