Six Steps from Zero to IDE (flatMap(Oslo) and ScalaDays Berlin 2018)

1 .Six steps from zero to IDE @olafurpg Watch this talk on YouTube 

2 .“The Scala IDE situation is quite possibly the worst out of all the industrial languages in existence. They’re all terrible, especially VS Code or Atom. Just use IntelliJ and hope for the best.” — r/scala, 10 points 

3 .Let’s build an IDE! 

4 .How hard can it be? 

5 . Pretty basic features • Work with my editor • Vim, Sublime Text, VS Code, Atom, Emacs, … • Work with my build tool • sbt, gradle, maven, pants, bazel, mill, cbt, … • Diagnostics • No spurious red squiggles! 

6 . Pretty basic features • Goto definition • Project sources, Scala deps, Java deps, classfiles • Auto completions • Scope, auto-import, type members, extension methods • Refactorings • Rename, organize imports, insert type annotation, … 

7 .Demo 

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9 . Rest of the talk • Language Server Protocol • “Zoo” of Scala language servers • Build Server Protocol • Conclusion 

10 . Scala Java Rust Python Vim Sublime VS Code Atom Emacs IntelliJ 

11 .Language Server Protocol Vim Scala Sublime VS Code Java Atom Rust Emacs IntelliJ Python 

12 . Java Editor Scala 

13 .JSON-RPC 

14 . Wait, JSON? On every keystroke? 

15 . Xi an editor for the next 20 years with with uncompromising performance 

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17 .LGTM, where do I sign up? 

18 .How to build an IDE 1. 2. 1. Configure LSP 2. Implement the rest of the IDE 

19 .Language Features 

20 .textDocument/publishDiagnostics 

21 .textDocument/publishDiagnostics 

22 .textDocument/definition 

23 .textDocument/definition 

24 . SemanticDB Symbol: spire.math.Complex#real(). Range: 10:18-10:22 Role: REFERENCE 

25 .textDocument/completions 

26 .textDocument/completions 

27 .textDocument/codeActions 

28 .textDocument/codeActions 

29 .