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![A recent contribution: error_highlight
3
json = { foo: { bar: { baz: 42 } } }
json[:foo][:barr][:baz]
# Ruby 3.0
$ ruby t.rb
t.rb:2:in `<main>': undefined method `[]' for nil:NilClass (NoMethodError)
# Ruby 3.1
$ ruby t.rb
t.rb:2:in `<main>': undefined method `[]' for nil:NilClass (NoMethodError)
json[:foo][:barr][:baz]
^^^^^^
Credit: The original author of its prototype is @yui-knk
https://github.com/ruby/ruby/pull/4470](https://image.slidesharecdn.com/rubykaigi-takeout-2021-endoh-210909003057/75/TypeProf-for-IDE-Enrich-Development-Experience-without-Annotations-3-2048.jpg)
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TypeProf for IDE: Enrich Development Experience without Annotations
- 1. TypeProf for IDE: EnrichDevelopment Experience without Annotations Yusuke Endoh (@mametter) RubyKaigi Takeout 2021
- 2. Yusuke Endoh /@mametter •A Ruby committer working at Cookpad w/ @ko1 • TypeProf: A static type analyzer for Ruby 3 •An esoteric Ruby programmer • See my RubyKaigi bio 2
- 3. A recent contribution:error_highlight 3 json = { foo: { bar: { baz: 42 } } } json[:foo][:barr][:baz] # Ruby 3.0 $ ruby t.rb t.rb:2:in `<main>': undefined method `[]' for nil:NilClass (NoMethodError) # Ruby 3.1 $ ruby t.rb t.rb:2:in `<main>': undefined method `[]' for nil:NilClass (NoMethodError) json[:foo][:barr][:baz] ^^^^^^ Credit: The original author of its prototype is @yui-knk https://github.com/ruby/ruby/pull/4470
- 4. "I love statictyping" … or do you? •Static typing is a means, not an end •The end is the modern development experience •Demo: TypeScript 4
- 5. The modern developmentexperience with TypeScript 5 On-the-fly error reporting
- 6. The modern developmentexperience with TypeScript 6 On-the-fly type inference
- 7. The modern developmentexperience with TypeScript 7 Go to definition
- 8. The modern developmentexperience with TypeScript 8 •Completion Completion
- 9. The modern developmentexperience with TypeScript 9 Hint for arguments
- 10. "I love statictyping" … or do you? •Static typing is a means, not an end •The end is the modern development experience • On-the-fly error reporting, go-to-definition, completion, argument hint, etc. •Q: Isn't it possible to achieve the experience without changing the Ruby language? • My answer is "Possible!" 10 (under some conditions)
- 11. Today's topic: TypeProffor IDE •A VSCode extension for Ruby • Powered by TypeProf (a static type analyzer for Ruby) •Demo 11
- 12. The modern developmentexperience with TypeProf for IDE 12 On-the-fly method signature
- 13. The modern developmentexperience with TypeProf for IDE 13 On-the-fly error reporting
- 14. The modern developmentexperience with TypeProf for IDE 14
- 15. The modern developmentexperience with TypeProf for IDE 15 On-the-fly type inference Completion
- 16. The modern developmentexperience with TypeProf for IDE 16 Hint for arguments
- 17. Demo: Summary •The moderndevelopment experience is possible without full type annotations by TypeProf for IDE 17
- 18. Agenda ➔ Recap: Typesfor Ruby 3 •TypeProf •TypeProf for IDE •Conclusion 18
- 19. Recap: Types forRuby 3 19 Name What RBS TypeProf Steep Sorbet The Ruby official type definition language A static type analyzer for Ruby A static type analyzer for Ruby A static type analyzer for Ruby
- 20. RBS: Ruby officialtype definition language 20 class User def initialize: (String) -> void def name: () -> String end
- 21. What a statictype analyzer does •Infers the types of a given program •Reports a potential runtime type error •Supports IDE 21 msg = "Hello, " + user.name msg: String msg = "Hello, " + user.naame Error!
- 22. Differences of eachstatic analyzer 22 Type inference Error reporting IDE support Analysis speed TypeProf 🙂Strong ☹️Weak No → Yes ☹️Slow Steep ☹️Weak 🙂Strong Yes 🙂Fast
- 23. Agenda •Recap: Types forRuby 3 ➔ TypeProf •TypeProf for IDE •Conclusion 23
- 24. The key ideaof TypeProf Runs a Ruby code in "type-level" Traditional interpreter def foo(n) n.to_s end foo(42) Calls w/ 42 Returns "42" TypeProf def foo(n) n.to_s end foo(42) Calls w/ Integer Returns String Object#foo :: (Integer) -> String 24
- 25. The user-facing featureof TypeProf •Ruby 3.0 • A type inference tool to create a prototype of RBS • No IDE support •Ruby 3.1~ • + IDE support! 25
- 26. Demo (memo) •Test insteadof type annotations •Passing an unknown type •Manual RBS specification •Flow-sensitive analysis •Manual overloading •Block, RBSWiki example 26
- 27. Demo: Tests insteadof type annotations 27 untyped String
- 28. Demo: Passing anunknown type 28 The method signature is changed to accept a new type Error in the callee side
- 29. Demo: Manual RBSspecification 29 Click here A prototype RBS is created
- 30. Demo: Manual RBSspecification (cont'd) 30 Error in the caller side # means RBS-defined
- 31. Demo: Flow-sensitive analysis 31 Noerror type case
- 32. Demo: Manual overloading 32 Noerror Write RBS for overloading Argument hint is selectable
- 33.
- 34. Demo: Works witha simple Rack app 34
- 35. Agenda •Recap: Types forRuby 3 •TypeProf ➔TypeProf for IDE •Conclusion 35
- 36. Language Server Protocol(LSP) 36 LSP client (vscode) LSP server (TypeProf for IDE) code changed error found complete "5.ti" maybe "5.times" 5.ti| Do you mean: 5.times 1 + "str" 1 + "str" Is this a bug?
- 37. Currently supported LSPfeatures •Show method signatures •Show potential errors •Go to definition of methods/variables •Find references of methods/variables •Completion •Show hint about method arguments 37
- 38. Not-implemented-yet LSP Features 38 Typehover Documentation • More challenging features • Auto refactoring (renaming), quick fix suggestion, etc. • Contribution is welcome!!!
- 39. Future work: theparser needs more ♥ •An AST node knows only the beginning and end of the source code •The parser returns nothing when syntax is broken • Cannot complete an incomplete call 39 current implementation desired behavior foo(k:)
- 40. About analysis performance •TypeProfis very slow • It traces "require 'foo'" (even if it is a gem) •TypeProf for IDE stops the analysis in one second • Nothing will be reported where it couldn't analyze within the time limit 40
- 41. How to makeTypeProf fast •Write RBS for gems • so that TypeProf don't have to analyze gem sources • Watch pocke's talk (Day 2) •Divide your application to components • and write RBS against their interfaces • We need experiment with a practical use case 41
- 42. Agenda •Recap: Types forRuby 3 •TypeProf •TypeProf for IDE •Implementation ➔Conclusion 42
- 43. Release plan •TypeProf forIDE will be released in Ruby 3.1 • Happy if you could play with it and give us feedback • How to run the development version https://gist.github.com/mame/86234de6a58352b9f994e0f8a6d6fbc2 (in Japanese) •Ready for production? • Experimental, but hopefully works for small programs • For large code base, please write RBS for gems first! 43
- 44. Special thanks •Hideki Miura •Rubycommitters: matz, akr, ko1, soutaro •Katsuhiro Ueno & Eijiro Sumii •Stripe team & Shopify team & Jeff Foster •Yuta Saito (@kateinoigakukun) • Many improvements of TypeProf for IDE 44
- 45. Conclusion •The modern developmentexperience is possible without full type annotations by TypeProf for IDE •Ruby 3.1 will bundle TypeProf for IDE 45