Write ruby code to change ruby code

Transcript

1. Write ruby code to
   change ruby code
   Richard Huang
   Xinmin Labs
   

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2. About Me
   Founder at Xinmin Labs
   Full Stack Developer
   Open Source Enthusiast
   @flyerhzm
   

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3. Problem
   

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4. Hey, let’s use rspec new syntax for project A
   Yes, sure, I love the rspec new syntax
   

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5. Hey, let’s use rspec new syntax for project B
   Hmmm…ok
   

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6. Hey, let’s use rspec new syntax for project C
   Oh, no, I don’t want to repeat it again
   

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7. Developers love upgrading
   and refactoring code
   

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8. Developers hate changing
   code again and again
   

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9. Automation
   

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10. Metric Tools
    

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11. Metric Tools
    • cane - fails your build if code quality thresholds
    are not met
    • reek - is a tool that examines Ruby classes,
    modules and methods and reports any code
    smells it finds.
    • rails_best_practices - is a tool to check the quality
    of rails code.
    • ……
    

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12. Tell you what to do,
    but can’t do for you
    

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13. IDE
    

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14. IDE
    • can rename class / method / variable name
    • can extract methods
    • can ……
    

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15. IDE
    • can’t customize
    

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16. Based on text
    

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17. Based on text
    Replace FactoryGirl.create with create
    !
    $ sed -i '' 's/FactoryGirl.create/create/g' spec/**/*.rb
    

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18. Based on text
    Replace FactoryGirl.create with create
    !
    !
    

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19. Based on text
    Hard to be accurate
    !
    !
    !
    !
    

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20. Based on text
    Hard to convert complicated cases
    !
    !
    !
    !
    

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21. Based on AST
    

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22. What’s AST
    AST is short for Abstract Syntax Tree
    

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23. What’s AST
    

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24. Why AST
    It is much more accurate to parse ruby code.
    

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27. How to use AST
    • ripper
    • ParseTree - https://github.com/seattlerb/parsetree
    • ruby_parser - https://github.com/seattlerb/ruby_parser
    • parser - https://github.com/whitequark/parser
    

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28. How to use AST
    

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29. Example
    transpec - https://github.com/yujinakayama/
    transpec
    

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31. Based on AST
    Accurate, but hard to write and read
    

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32. Synvert
    https://github.com/xinminlabs/synvert
    

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33. Demo
    http://xinminlabs.github.io/synvert/
    

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35. Synvert
    • Add useful attributes to AST nodes
    !
    • Provide DSL to parse and rewrite code
    

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36. Attributes for AST node
    

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37. Attributes for AST node
    

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38. Attributes for AST node
    

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39. Attributes for AST node
    Check out more attributes
    http://xinminlabs.github.io/synvert/rules/
    

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40. DSL
    • within_file / within_files
    • with_node / within_node
    • if_exist_node / unless_exist_node
    • append / insert / insert_after / replace_with /
    remove
    • ……
    

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41. DSL
    Check out more DSL
    http://xinminlabs.github.io/synvert/dsl/
    

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43. Playground
    http://synvert-tools.herokuapp.com/
    

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44. Snippets
    https://github.com/xinminlabs/synvert-snippets
    

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45. Want more?
    • Fork and send pull request
    • Open issues on github
    • Hire us to refactor your project
    

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46. Q&A
    !
    Thank you
    

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