Improving the development experience with language servers

Providing a state of the art development experience greatly contributes to Ruby’s goal of making developers happy. A complete set of editor features can make a big difference in helping navigate and understand our Ruby code. Let’s explore a modern way of enhancing editor functionality: the language server protocol (LSP). What it is, how to implement it and how an LSP server like the Ruby LSP can make writing Ruby even better.

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1. Vinicius Stock Improving the development experience with language servers
2. Vinicius Stock Senior dev @ Ruby DX team Shopify Twitter: @vinistock GitHub: @vinistock https://vinistock.com
3. Let’s look back
4. Vim Ruby Source: https://code.visualstudio.com/api/language-extensions/language-server-extension-guide Editors Plugins JavaScript Rust Go Sublime VS Code Neovim
5. No standard set of language speci fi c features
6. Vim Ruby Source: https://code.visualstudio.com/api/language-extensions/language-server-extension-guide Editors Plugins JavaScript Rust Go Sublime VS Code Neovim Syntax highlighting Go to de fi nition Linting
7. Language Server Protocol Set of standard features Source: https://microsoft.github.io/language-server-protocol/speci fi cation Background server
8. Language server STDIN Editor (Client) Request (JSON) Response (JSON) STDOUT STDERR
9. Vim Ruby Source: https://code.visualstudio.com/api/language-extensions/language-server-extension-guide Editors Language server JavaScript Rust Go Sublime VS Code Neovim Client Client Client Client Plugin or built-in
10. Source: https://microsoft.github.io/language-server-protocol/speci fi cation
11. Source: https://microsoft.github.io/language-server-protocol/speci fi cation
12. initialize textDocument/ didOpen textDocument/ foldingRange Language server Editor (Client) capabilities Activate language server Open fi le foo.rb Ranges Edit foo.rb textDocument/ didChange Ranges textDocument/ foldingRange
13. Ruby LSP https://github.com/Shopify/vscode-ruby-lsp https://github.com/Shopify/ruby-lsp
14. What does it do?
18. Let’s see how to server works
19. Loop STDIN Read JSON request Run request STDOUT Write JSON response
20. Ruby LSP Text synchronization Parsing Hover Document highlight Folding range Document symbol
22. How can we implement it?
23. Source: https://microsoft.github.io/language-server-protocol/speci fi cation
24. Source: https://microsoft.github.io/language-server-protocol/speci fi cation
26. AST Ruby code Analysis Parse Traverse
27. What’s parsing?
28. AST simpli fi ed from the syntax_tree gem CLASS BODY CONST DEF IDENT BODY STRING
29. We need a way of going through each node
31. BODY CONST DEF IDENT BODY STRING CLASS
32. We’re ready to implement folding range
38. Synchronize text edits Parse Folding range Document symbol Document link Semantic highlighting Inlay hint Selection range AST
39. Ruby LSP https://github.com/Shopify/vscode-ruby-lsp https://github.com/Shopify/ruby-lsp
40. Folding range Document symbol Document link Semantic highlighting Inlay hint Selection range Hover Format on type Document highlight Format on save Diagnostics Code actions
41. The future of Ruby tooling
42. Rich features Cross editor Gradual typing Interactive debugging Any editor can be a fully featured IDE
43. Thank you!
44. • https://github.com/Shopify/vscode-ruby-lsp • https://github.com/Shopify/ruby-lsp • https://code.visualstudio.com • https://github.com/ruby-syntax-tree/syntax_tree • https://microsoft.github.io/language-server-protocol/speci fi cation • All screenshots made with: https://code.visualstudio.com References