Ruby Parser Basics

Kyobashi.rb Offline #1 『Ruby Parser Basics』のスライド
https://kyobashirb.connpass.com/event/307312/

Transcript

1. Ruby Parser Basics @y d a h Ky ob a sh i .r b Of f l i ne #1 2 02 4 .0 2 .0 5 (Mo n .)
2. ɾ Name: Yudai Takada ɾ GitHub: @ydah / X: @ydah_ ɾ Software Engineer at ANDPAD, Inc. ɾ Co-Founder of Kyobashi.rb ɾ Member of RuboCop RSpec team ɾ Contributor of Lrama ɾ Implementation of Parameterizing rules self.inspect
3. Today’s talk
4. Ruby Parser Basics
5. Age of Parser!
6. In Ruby 3.3.0 release notes
7. Two new parsers?!
8. • Lrama • A pure Ruby parser generator, not a parser • Created as a CRuby parser generator to replace GNU Bison • By adding new features, Lrama aims to make parse.y simpler and more maintainable Two new Ruby parsers (1)
9. • Prism • A Ruby parser library written by hand from scratch • It is under development to replace the Ruby parser with Prism • For node structure, AST is also designed from scratch Two new Ruby parsers (2)
10. • Lexer • Reads the source code character by character and returns a single token when it is meaningfully cohesive • Parser • Check the Lexer output token for grammatical conformance and create an AST • Appropriate error handling is done for grammatically incorrect programs • Compiler • Ruby compiles into machine language for virtual machines(YARV), and then the virtual machines execute Components related to parsing
11. the process by which code becomes executablE Source Code
12. the process by which code becomes executablE Token Source Code Lexical analysis
13. the process by which code becomes executablE Token AST Source Code Parsing
14. the process by which code becomes executablE 0101 0101 Token AST ISeq Source Code Compile
15. • A type of bottom-up parsing • Lookahead Left to Right, Rightmost derivation parser • Parser generators such as racc, Bison, and Lrama generate parsers of this type What is LALR(1) parser?
16. def method_name(parameters) "method body" end Parsing procedure
17. def method_name lparen parameter rparen string end Parsing procedure
18. method_name lparen parameter rparen ↓ Parsing procedure def string end
19. ↓ method_name lparen parameter rparen Parsing procedure def string end
20. ↓ lparen parameter rparen Parsing procedure def method_name string end
21. ↓ lparen parameter rparen Parsing procedure def method_name string end
22. ↓ lparen parameter rparen Parsing procedure def method_name string end
23. ↓ lparen parameter rparen Parsing procedure def method_name string end
24. def method_name lparen parameter rparen string end ↓ Parsing procedure
25. def method_name(parameters) "method body" end Parsing procedure
26. def method_name(parameters) "method body" end Method de fi nition Parsing procedure
27. • Ruby parsers are one of the hottest topics • Maybe, there will be sessions at RubyKaigi 2024 where the progress of each (Lrama and Prism) is presented (No, there must be.) • Please enjoy the Parser session! Finally…
28. end