Ruby 2.0 Walkthrough: The Best Bits

A quick overview of a few of the best bits in Ruby 2.0.

Transcript

1. RUBY 2.0
   WALKTHROUGH
   

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2. The Best Bits
   THE RUBY 2.0 RUNTHROUGH
   

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3. A sprint, not a stroll
   

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4. BIG PARTS
   

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5. Refinements
   Experimental scope-limited
   monkey patching
   

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6. module FloatDivision
   refine Fixnum do
   def /(other); self.to_f / other; end
   end
   end
   class MathFun
   using FloatDivision
   def self.ratio(a, b)
   a / b
   end
   end
   p MathFun.ratio(6, 8)
   THE OLD IDEA (no longer works)
   

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7. module FloatDivision
   refine Fixnum do
   def /(other); self.to_f / other; end
   end
   end
   class MathFun
   using FloatDivision
   def self.ratio(a, b)
   a / b
   end
   end
   p MathFun.ratio(6, 8)
   

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8. module FloatDivision
   refine Fixnum do
   def /(other); self.to_f / other; end
   end
   end
   using FloatDivision
   class MathFun
   def self.ratio(a, b)
   a / b
   end
   end
   p MathFun.ratio(6, 8)
   Main context is OK
   

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9. Keyword Arguments
   definitely a: “pretty”, good:
   “addition”, to: “the language”
   

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10. def some_method(options = {})
    defaults = { x: 10, y: 20, z: 30 }
    options = defaults.merge(options)
    p options
    end
    some_method x: 1, y: 2
    

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11. def some_method(x: 10, y: 20, z: 30)
    p x, y, z
    end
    some_method x: 1, y: 2, z: 3
    

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12. def some_method(x: 10, **rest)
    p x, rest
    end
    some_method x: 1, y: 2, z: 3, c: “x”
    

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13. Enumerator::Lazy
    Lazy enumeration, finally made easy.
    

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14. infinite_range = (0..Float::INFINITY)
    infinite_range.select { |num| num % 74 == 0 }
    

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15. infinite_range = (0..Float::INFINITY)
    e = infinite_range.lazy.select { |num| num % 74 == 0 }
    puts e.next
    puts e.next
    puts e.next
    

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16. Module#prepend
    

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17. module Bar
    def my_method
    "inside the module"
    end
    end
    class Foo
    include Bar
    def my_method
    "inside the class"
    super
    end
    end
    x = Foo.new
    p x.my_method
    1
    2
    

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18. module Bar
    def my_method
    "inside the module"
    super
    end
    end
    class Foo
    prepend Bar
    def my_method
    "inside the class"
    end
    end
    x = Foo.new
    p x.my_method
    1
    2
    

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19. INCLUDE PREPEND
    Foo class
    Bar module
    x object
    NEITHER
    Foo class
    x object
    Object class
    Object class
    Foo class
    Bar module
    x object
    Object class
    

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20. DETAILS
    

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21. ABI Breakage
    Changes to the Application Binary
    Interface
    

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22. Regex engine changed
    From Oniguruma to Onigmo
    

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23. %{this\r\nis\n\ncool\vhello!}.gsub(/\R/, '')
    

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24. RubyGems 2.0
    Lots of refactoring, initial support
    for stdlib gemification, gem search
    is now remote, arbitrary
    metadata support & more.
    

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25. RDoc 4.0
    Adds Markdown support & ri can
    now show pages (e.g. READMEs
    with ri rdoc:README)
    

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26. %i and %I
    To form arrays of symbols, like %w
    does for words and arrays
    

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27. %i{a b c} == [:a, :b, :c]
    %I{ #{(rand(26) + 65).chr} } == [:Y]
    

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28. UTF-8 is default
    source encoding
    No more # encoding: utf-8 (if you
    don’t want)
    

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29. Bitmap garbage
    collector
    Faster, more efficient
    

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30. CSV.load and
    CSV.dump gone
    Not considered such a good idea
    in light of the early 2013 YAML
    vulnerabilities
    

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31. String#chars, #lines,
    #codepoints, etc.
    Now return arrays rather than
    enumerators.
    Use #each_char, #each_line, etc.
    instead if you need enumerators.
    

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32. TracePoint
    A more object oriented alternative
    to set_trace_func
    

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33. tracer = lambda do |event, file, line, id, binding, klass|
    to_display = [event, File.basename(file), line, klass, id]
    puts "%10s in %s at line %-2d %s:%s" % to_display
    end
    set_trace_func tracer
    # .. normal code here ..
    

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34. tracer = TracePoint.new do |tp|
    to_display = [tp.event, File.basename(tp.path), tp.lineno,
    tp.defined_class, tp.method_id]
    puts "%10s in %s at line %-2d %s:%s" % to_display
    end
    tracer.enable
    # .. normal code here ..
    

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35. respond_to?
    respond_to? against a protected
    method now returns false
    

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36. Method transplants
    with define_method
    Now accepts UnboundMethods
    

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37. module M
    def foo; "foo"; end
    end
    define_method :foo, M.instance_method(:foo)
    p foo
    

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38. Array#bsearch
    Range#bsearch
    Binary search for monotonic
    collections
    

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39. [1, 4, 9, 13, 14, 22, 40].bsearch { |i| p i; i >= 6 }
    # 13
    # 4
    # 9
    # => 9
    (1..1000).bsearch { |i| i > 372 }
    

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40. __dir__
    Like __FILE__ but for the current
    source file’s directory
    Equivalent to
    File.dirname(File.realpath(__FILE__))
    

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41. to_h and Hash()
    A new convention. The hash equivalent
    to #to_a
    A key use is with Struct and OpenStruct
    

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42. User = Struct.new(:name, :age, :status)
    me = User.new("Peter", 31, :admin)
    me.to_h
    ENV.to_h
    Hash(nil) # => {}
    Hash([]) # => {}
    

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43. FIN
    https://cooperpress.com/
    

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