Crystal & Ruby - Applying learnings from a compiled language

We all enjoy the flexibility and expressiveness that languages like Ruby give us, but such flexibility is also paired with the unknown. Dealing with dynamic data and runtime conditions can lead to unknown scenarios and runtime errors.

Compiled languages, specially today offer a fresh perspective and help us developers better understand and shape our code.

This talk aims to discover certain techniques transferred from compiled languages’ realm and transfer those to dynamic languages like Ruby. Will talk from my experience working on mid-size Ruby projects (8K+ LOC).

Presented at Paris.rb Conference, June 2018

Transcript

1. Crystal & Ruby
   Applying learnings from a compiled language
   

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2. Luis Lavena
   Twitter: @luislavena
   GitHub: luislavena
   

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5. area17.com
   

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6. WARNING: Technical talk ahead
   Important announcement follows...
   

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7. vs.
   

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9. Compiled vs. Interpreted
   

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10. Ruby VM
    require
    Read source
    Tokenize (lexer)
    Build AST (parser)
    Build ISeq
    Execute ISeq
    Ruby
    

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11. OS
    Read source
    Tokenize (lexer)
    Build AST (parser)
    Codegen
    Execute
    Native Code (obj)
    Link
    Compilers
    Analyze/Infer/Optimize
    

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15. Crystal Language
    ● Ruby-like syntax
    ● Types and Inference
    ● Generics
    ● Macros
    ● Self-hosted
    ● LLVM-powered
    ● Native, single-executable
    

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16. Crystal Language
    ● Ruby-like syntax
    ● Types and Inference
    ● Generics
    ● Macros
    ● Self-hosted
    ● LLVM-powered
    ● Native, single-executable
    

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17. Types and Inference
    

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18. Types and Inference
    a = [1, 2, 3].map { |x| x + 3 }
    pp a # => a = [4, 5, 6]
    pp typeof(a) # => Array(Int32)
    b = [1, "a", 'b']
    pp typeof(b) # => Array(String | Int32 | Char)
    # b << 12.5 # => Compile error (Float32)
    

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19. Methods and inference
    def add(one, two)
    one + two
    end
    add 30, 12 # Int32, Int32 => Int32
    add "a", "b" # String, String => String
    add "a", 'b' # Compile error
    

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20. Methods and inference
    def work(worker)
    worker.something!
    end
    work Worker.new # OK
    work nil # Compile error (no method `something!` for `nil`)
    

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21. Methods and inference
    def work(worker)
    if worker
    worker.something!
    end
    end
    work Worker.new # OK
    work nil # => nil
    

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22. Methods & signatures
    def add(one : Int32, two : Int32)
    one + two
    end
    add 30, 12 # Int32, Int32 => Int32
    add "a", "b" # Compile error
    

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23. Ruby
    ● Types syntax will be hard to implement
    ● Probably method signatures will be added in Ruby 3x3
    ● Type checkers possible (ie. Sorbet by Stripe)
    https://sorbet.run/
    

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25. Code techniques
    

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26. Code techniques
    Acknowledge that nil exists
    

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27. def work(option)
    return option + 10
    end
    work 5 # => 15
    work nil # => Runtime Exception
    def work(option)
    if option
    return option + 10
    end
    end
    work 5 # => 15
    work nil # => nil
    Acknowledge that nil exists
    

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28. Code techniques
    Acknowledge that nil exists ✔
    Accessing variables across threads
    

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29. class Worker
    def work
    if @condition
    @condition.something!
    end
    end
    end
    class Worker
    def work
    if value = @condition
    value.something!
    end
    end
    end
    Accessing variables across threads
    

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30. Code techniques
    Acknowledge that nil exists ✔
    Accessing variables across threads ✔
    

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31. Coding resources
    ● Ruby typechecker: Sorbet
    https://sorbet.run/
    

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32. Optimization techniques
    

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33. Optimization techniques
    Load time
    

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34. require
    Read source
    Tokenize (lexer)
    Build AST (parser)
    Build ISeq
    Execute ISeq Ruby VM
    Memory
    I/O
    

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35. $ cat example.rb
    a = 30
    puts a + 12
    $ ruby -e 'File.binwrite("example.yarb",
    RubyVM::InstructionSequence.compile_file("example.rb").to_
    binary)'
    $ ls -l
    total 4
    -rw-r--r-- 1 luis luis 19 Jun 28 10:07 example.rb
    -rw-r--r-- 1 luis luis 818 Jun 28 10:07 example.yarb
    

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36. $ ruby -e
    'RubyVM::InstructionSequence.load_from_binary(File.binread
    ("example.yarb")).eval'
    42
    

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37. require
    Read source
    Tokenize (lexer)
    Build AST (parser)
    Build ISeq
    Execute ISeq
    Ruby VM
    I/O
    Read bytecode
    

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38. Bootsnap
    ● Compiles .rb into YARB bytecode
    ● Hooks require and loads instead of parsing
    ● Optimizes lookup of $LOAD_PATH
    

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39. ~35%
    Load time speed up using Bootsnap
    Mid-size Rails app (~6k LOC)
    

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40. Optimization techniques
    Load time ✔
    

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41. Optimization techniques
    Load time ✔
    Installation time and dependencies
    

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43. UPDATING NOKOGIRI!!!
    

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44. But, what if there is an alternative?
    

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45. $ time gem install nokogiri-1.8.3.gem
    …
    real 5m34.507s
    $ gem compile nokogiri-1.8.3.gem
    …
    $ time gem install nokogiri-1.8.3-x86_64-linux.gem
    …
    1 gem installed
    real 0m4.947s
    

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46. gem-compiler
    ● RubyGems plugin (`gem compile ...`)
    ● Pre-compile gems for the current platform
    ● Plays nice with Bundler
    (`bundle package` and `bundle install --local`)
    ● Reduces install time
    (compile nokogiri from ~5 mins to ~4 seconds)
    ● Reduces bandwidth usage
    (nokogiri from ~8.8MB to ~700KB)
    

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47. Optimization techniques
    Load time ✔
    Installation time and dependencies ✔
    Code-reviews and code style
    

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48. “This PR is excellent! Event the
    inconsistent style and spaces used for
    your hashes, the lack of parenthesis on
    methods and let’s not forget the usage of
    tabs!”
    - Anonymous Ruby developer on GitHub
    

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49. Formatting code
    ● Reduces bikeshedding
    ● Consistent readability following official styleguides
    ● Improves contribution
    ● Broad implementation and success on other languages:
    Golang, Rust, Elixir
    ● Proactive vs. Passive
    

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50. $ cat example.rb
    def hello name
    puts "Hello #{name}!!!"
    end
    $ rufo example.rb
    $ cat example.rb
    def hello(name)
    puts "Hello #{name}!!!"
    end
    rufo: Ruby formatter
    

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51. Optimization techniques
    Load time ✔
    Installation time and dependencies ✔
    Code-reviews and code style ✔
    

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52. Optimization resources
    ● Load time: Bootsnap
    http://github.com/Shopify/bootsnap
    ● Pre-compiled extensions: gem-compiler
    https://github.com/luislavena/gem-compiler
    ● Code formatting: rufo
    https://github.com/ruby-formatter/rufo
    

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54. Thank you!
    

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