Ruby's past, present, and future (RubyConf AR)

"This presentation delves into the past, present, and future of Ruby. This presentation covers various topics including the reason why Ruby was created, Ruby's evolution, its current status, and future plans."

At RubyConf Argentina 2011
http://rubyconfargentina.org/en/agenda

Transcript

1. Ruby's past, present, and future Nov 8th, 2011 Shugo Maeda and Yutaka Hara
2. Self introduction • Shugo Maeda • Twitter ID: @shugomaeda • A Ruby committer • The co-chairman of the Ruby Association • A director of Network Applied Communication Laboratory Ltd.
5. Any questions? :-)
6. Self introduction • Yutaka HARA • Twitter ID: @yhara_en • Github ID: yhara – BiwaScheme (R6RS Scheme in JS) – ruby-dev.info ([ruby-dev] translation to En) – Esoteric Language designer
7. Topics • Ruby's past, • present, • and future
8. Ruby's past
9. The birth of Ruby • Born on February 24th 1993 – Just the name • Father: Yukihiro Matsumoto, a.k.a. Matz • Godfather: Keiju Ishitsuka
10. How was the name Ruby chosen? keiju> Come to think of it, did you come up with the name of the language? matz> Hmm, if it's similar enough to shells, Tish. matz> But I need a more cool name ... keiju> ruby keiju> Of course, it should be a jewel name matz> Is it taken from ruby annotation? matz> Why should it be a jewel name? matz> Affected by Mitsubishi? keiju> perl matz> I see
11. Ruby 0.49 • The oldest version available – ftp://ftp.ruby-lang.org/pub/ruby/1.0/ruby-0.49.tar.gz – (see [ruby-talk: 206778]) • Released privately in July 1994
12. Hello world in Ruby 0.49 print("Hello world\n") • Is it the same as Ruby 1.9? – Both yes and no – You could not omit parentheses in Ruby 0.49 print "Hello world\n" #=> ERROR!
13. Hello world in Python $ python2.6 -c 'print "hello"' hello $ python3.1 -c 'print "hello"' File "<string>", line 1 print "hello" ^ SyntaxError: invalid syntax $ python3.1 -c 'print("hello")' hello
14. CoC • Convention over Configuration • Convenience over Consistency • In Python, the print statement was removed for consistency • In Ruby, parenthesis omission was supported for convenience
15. Example code in Ruby 0.49 class greeting # (1) def !=(array) # != can be overridden do array.each using x # (2) @say_hello(x) end fail("error") # (3) end def # (4) def @say_hello(x) # (5) print("Hello, ", x, "!\n") end def end class
16. Example code in Ruby 0.49 (cont'd) protect # (1) g = greeting.new() g != ("Matz" :: "Larry") # (2) print("success\n") resque # (3) print("failed\n") end protect • resque is a typo by Matz (not us!)
17. It looks very different ... • But it already had essential features of Ruby – Interpreter – Pure object oriented – Dynamically typed – Garbage collection – Blocks – ...
18. What was Ruby created for? • For UNIX • For easy object-oriented programming • For fun
19. Ruby for UNIX • Ruby was created for UNIX • Developed on SONY NEWS-OS • Easy scripting like Perl • APIs tied closely to UNIX/C – Not self-contained in contrast to Smalltalk – Better UNIX – Emulation for non-Unix OS
20. APIs came from UNIX/C • open • read • gets • write • printf • puts • fcntl • ioctl • stat • select • getuid • setuid • fork
21. Better UNIX • Some API's origins are in UNIX/C • However, their behavior is improved • Examples – IO#eof? returns true before read fails while feof(3) does't. – IO.select can be used for buffered IO while select(2) can't.
22. Ruby for object-oriented programming • Problem – OOP is excellent – But too heavy for daily scripting • Solution – Non-OO style syntax – Pure object-oriented semantics
23. Non-OO style syntax def fib(n) if n < 2 return n else return fib(n - 2) + fib(n - 1) end end puts fib(20) • fib looks like just a function, isn't it?
24. Pure object-oriented semantics • Receivers can be omitted – fib(20) is a short form of self.fib(20) • At top level: – self is an instance of Object – def defines a method in Object • All data (even integers) are objects • Most operators such as +, - are methods
25. Ruby for fun • For Matz's fun – Creating a new language was his dream • For your fun – Who are YOU? – YOU = programmers
26. Shugo's first contact of Ruby • In 1997 • He was a Java programmer – Please don't throw a stone at me! • Posted my regexp library in a Java ML • Someone said "Ruby's Regexp is better" • He fell in love with Ruby, threw away Java • Got involved with Ruby development
27. How he learned to stop worrying and love Ruby • His worries were: – Ruby is unpoplular, isn't it? – Ruby is slow, isn't it? – Dynamic typing is unsafe, isn't it?
28. Ruby is unpopular, isn't it? • Yes, it was. – No books – No real world applications – No recruitment for Ruby programmers • But all the more, Ruby was worth learning – Ruby was the "Secret Weapon" – Read Paul Graham's "Beating the Averages"
29. Ruby is slow, isn't it? • Yes, it's slow because it's: – Dynamically typed • Can't use type information for optimization – Pure object oriented • No primitive types like int in Java – Extremely dynamic • Method redefinition etc... • But, the slowness is acceptable – At least for I/O bound applications
30. Dynamic typing is unsafe, isn't it? • Yes, so write test code • Shugo sais... – Ruby programming is like riding a motorcycle • You can go anywhere anytime you want • But you may sometimes slip down – It's fun for me
31. Ruby 1.0 - 1.6 • 1997 - 2002 • Many changes
32. Ruby 1.8 • The first release was on Aug 4th 2003 • Stable • The most successful version of Ruby
33. Ruby 1.8 is past • 1.8.8 – Never released • 1.8.7 – Only bug fixes until June 2012 – Only security fixes until June 2013
34. Some of Shugo's past works • puts • callcc • protected
35. puts • writeln and println were rejected – They came from Pascal and Java – Matz likes neither Pascal nor Java • Shugo proposed the name puts [ruby-dev:771] – It came from C (Matz likes C) – The behavior is a bit weird • puts [1,2,3]
36. calcc • Introduced callcc into Ruby [ruby-dev:4206] • callcc = call with current continuation • Provides first class continuations – Came from Scheme • Ruby's Black Magic! – (.*)eval – callcc – set_trace_func – ObjectSpace
37. callcc • Saves & loads interpreter state – Used like “goto”, but can jump between methods • Not encouraged to use – Removed from built-in libraries in Ruby 1.9 – It may be completely removed in Ruby 2.0
38. Example of callcc 01: require "continuation" 02: 03: cont = nil 04: x = callcc { |c| 05: cont = c 06: "first" 07: } 08: p x 09: if x == "first" 10: # go to line 04 with value "second" 11: cont.call("second") 12: end
39. Non-deterministic problems • Problem from the “SICP” book – Baker, Cooper, Fletcher, Miller, and Smith live on different floors of an apartment house that contains only five floors. – Baker does not live on the top floor. – Cooper does not live on the bottom floor. – Fletcher does not live on either the top or the bottom floor. – Miller lives on a higher floor than does Cooper. – Smith does not live on a floor adjacent to Fletcher's. – Fletcher does not live on a floor adjacent to Cooper's. – Where does everyone live?
40. Solution require "amb" a = Amb.new baker = a.choose(1, 2, 3, 4, 5) cooper = a.choose(1, 2, 3, 4, 5) fletcher = a.choose(1, 2, 3, 4, 5) miller = a.choose(1, 2, 3, 4, 5) smith = a.choose(1, 2, 3, 4, 5) a.assert([baker, cooper, fletcher, miller, smith].uniq.length == 5) a.assert(baker != 5) a.assert(cooper != 1) a.assert(fletcher != 1 && fletcher != 5) a.assert(miller > cooper) a.assert((smith - fletcher).abs != 1) a.assert((fletcher - cooper).abs != 1) p [baker, cooper, fletcher, miller, smith]
41. Implementation of Amb class Amb ... def choose(*choices) choices.each { |choice| callcc { |fk| @back << fk return choice } } failure end def failure @back.pop.call end def assert(cond) failure unless cond end
42. Why is callcc evil? • Objects are mutable in Ruby – callcc doesn't restore the state of objects • C calls and Ruby calls are nested in Ruby – C calls are also restored by callcc – Most C code doesn't take care of it • Even built-in methods used to crash – [ruby-dev:24301] Hash#rehash [ruby-dev:24303] Hash#each [ruby-dev:24378] sort_by [ruby-dev:24432] String#gsub! [ruby-dev:24463] each_with_index [ruby- dev:24487] Dir.glob [ruby-dev:24499] each_slice
43. protected • Method visibility • Equivalent to Java's protected • Useful to implement binary operators def ==(other) @value == other.value # error if value is private end protected def value; @value; end
44. “abnormal” use of protected • Often seen in Rails applications • Use private instead if possible – private methods can be called from subclasses class ApplicationController < ActionController::Base before_filter :login_required protected # Why not private? def login_required ...
45. Ruby's present
46. Ruby's present • Popularity • JIS/ISO Standard • Ruby 1.9 • Recent trends in Ruby
47. Mainstream Language • TIOBE Index (October 2011) • "A" means mainstream
48. Ruby on Rails • Rails made Ruby more popular • Rails may be more popular than Ruby
49. Difference between Ruby and Rails?
50. Same question in Japan
51. Ruby standard • JIS X 3017 – published on March 22nd 2011 – JIS = Japanese Industrial Standards • ISO/IEC JTC1 Fast-Track procedure – "Voting closed 6 September; it received a 100% approval. Only Japan made comments." • http://grouper.ieee.org/groups/plv/DocLog/300- 399/360-thru-379/22-WG23-N-0364/n0364.pdf
52. Why Ruby standard? • Business reasons – Tranquilizer for enterprise users – Necessary for government procurement • Technical reason – Written specification may help development • I have found some bugs in CRuby:) • The standard may also have bugs:(
53. How Ruby has been standardized • Codified the existing (implicit) specification – No new invention by the standardization WG – Ruby development is kept free • Asked public comments from the community – Over 100 comments
54. Ruby 1.9 • New implementation • New syntax • Other new features
55. New implementation • YARV = Yet Another Ruby VM • It's now the Ruby VM • Word-code interpreter – The size of opcode and operands is the size of pointers • Made 1.9 faster than Ruby 1.8
56. New syntax • New hash syntax • New syntax for blocks and lambda • Extended splat
57. New hash syntax # Normal hash syntax h = {:a => 1, :b => 2} # New hash syntax h = {a: 1, b: 2} # Specify method options (keyword argument) foo opt1: 1, opt2: 2
58. New syntax for blocks and lambda # Default value for block parameter foo = lambda{|a, b, c=nil| … } # Passing block to Proc foo = lambda{|a, b, &block| … } # New lambda syntax (“stabby lambda”) add = ->(x, y) { x + y } p add.call(1, 2) # (a) normal way p add[1, 2] # (b) shorter way p add.(1, 2) # (c) !?
59. Extended splat # Splat in the middle # (1) def foo(a, *b, c) … # (2) bar(a *b, c) # (3) baz{|a, *b, c| … } # (4) a, *b, c = ary # Multiple splats x = [1,2,3]; y = [4,5,6] ary = *x, *y foo *x, *y
60. Other new features • M17N • Fiber • Enumerator
61. M17N • M17N = multilingualization • Code Set Independent (CSI) – Not UCS Normalization – Unicode is just one of supported character sets • Strings are character strings – In Ruby 1.8, strings are byte strings
62. Fiber • Semi-coroutines • Coroutines are similar to subroutines – But have multiple entry points • Semi-coroutines are restricted coroutines – Parent/child relationship
63. Example of Fiber f = Fiber.new { print ”1, ” Fiber.yield # Stop! print ”2” Fiber.yield # Stop! print ”3” } f.resume #=> 1, f.resume #=> 2, f.resume #=> 3
64. Enumerator • Some methods return Enumerator – String#lines, String#chars etc. • Enumerator is a lazy list • Enumerator is Enumerable • Enumerator is an external iterator
65. Example of Enumerator s = <<EOF ruby perl python EOF puts s.lines.each_with_index.select { |line, i| /p/ =~ line }.map { |line, i| format("%3d: %s", i + 1, line) }
66. Enumerator as an external iterator lines = ARGF.lines 10.times do puts lines.next end
67. Ruby 1.9 is present • Everyone should use it now • Migration from Ruby 1.8 to 1.9 is easier than migration from Rails 2 to Rails 3
68. Recent trends in Ruby • Functional programming • Monkey patching
69. Functional programming • "a programming paradigm that treats computation as the evaluation of mathematical functions and avoids state and mutable data" (from Wikipedia)
70. Concepts in functional programming • Pure functional functions – No side effects – Expressions over statements • Higher-order functions – Take functions as arguments – Return functions
71. Functional programming in Ruby • Advantages – Blocks and lambda – Methods like higher-order functions • Enumerable#map etc... – Almost everything is an expression • Disadvantages – No real function – Almost everything is mutable
72. 1.9 features for functional programming • Proc#curry • Enumerable#flat_map
73. Proc#curry add = lambda { |x, y| x + y } curried_add = add.curry # => lambda {|x| lambda {|y| x + y}} add1 = curried_add.call(1) p add1.call(2) #=> 3 • Useful for partial application
74. Enumerable#flat_map def queens(n, k = n) if k == 0 [[]] else queens(n, k - 1).flat_map {|qs| (1..n).map {|col| [k, col]}.select {|q| qs.all? {|q2| q[1] != q2[1] && (q[0] - q2[0]).abs != (q[1] - q2[1]).abs } }.map {|q| [q, *qs]} } end end
75. Monkey patching • Classes and modules are also mutable • Runtime extension of classes and modules
76. Use cases of monkey patching • Workaround for a bug of a library • Plugin system like Rails • Extensions of built-in classes – Often used for internal DSLs @empty_array.size.should == 0
77. alias_method_chain ActionView::Helpers::RenderingHelper.module_eval do def render_with_update(options = {}, locals = {}, &block) if options == :update update_page(&block) else render_without_update(options, locals, &block) end end alias_method_chain :render, :update end
78. Ruby's future
79. Ruby 2.0 • Had been a vaporware for a long time – Matz mentioned Ruby 2.0 at RubyConf 2001 • Something like Web 2.0?
80. Now Ruby 2.0 is real $ ruby-trunk -v ruby 2.0.0dev (2011-10-31 trunk 33588) [i686-linux] $ fgrep -B2 '2.0' ChangeLog Wed Oct 19 17:06:54 2011 Yukihiro Matsumoto <matz@ ruby-lang.org> * version.h (RUBY_VERSION): finally declare start of 2.0 work! $
81. Ruby 2.0 is future • It's near future • Current schedule – Aug 24th 2012 big-feature freeze – Oct 24th 2012 feature freeze – Feb 2nd 2013 2.0 release
82. New features in Ruby 2.0 • Accepted features – Keyword arguments – Module#prepend • Features under discussion – Enumerable#lazy – Refinements
83. Keyword arguments # Existing syntax def foo(opts={}) opts[:opt1] ||= ”foo” if opts[:opt2] … # Planning syntax def foo(opt1: "foo", opt2: nil) if opt2 ... end # Calling is the same foo(opt1: 1, opt2: 2) – Discussion ongoing: [Redmine #5474]
84. Module#prepend • Replaces alias_method_chain • • • • • • – Discussion ongoing: [Redmine: #1102] module RenderUpdate def render(options = {}, locals = {}, &block) if options == :update update_page(&block) else # call the original RenderingHelper#render super(options, locals, &block) end end end ActionView::Helpers::RenderingHelper.module_eval do prepend RenderUpdate end
85. Enumerable#lazy • Proposed by @yhara_en def pythagorean_triples (1..Float::INFINITY).lazy.flat_map {|z| (1..z).lazy.flat_map {|x| (x..z).lazy.select {|y| x**2 + y**2 == z**2 }.map {|y| [x, y, z] } } } end p pythagorean_triples.take(10)
86. Considerations for Enumerable#lazy • Is lazy a good name? – Is view, delay, or defer better? • Is lazy necessary? – Why not Enumerator#map returns an Enumerator instead of an Array?
87. Refinements • Provides “scoped” monkey patching module MathN refine Fixnum do def /(other) quo(other) end end end module Foo using MathN p 1 / 2 #=> (1/2) end p 1 / 2 #=> 0
88. Considerations for Refinements • Performance issue – It's slow even if refinements are not used • Scope of refinements – Lexical scoping is safe, but not flexible – Do we need refinement propagation? • Discussions: [Redmine: #4085]
89. Who creates Ruby's future? • It's You! • Redmine: – http://redmine.ruby-lang.org/projects/ruby-trunk/ • Mailing list: – http://www.ruby-lang.org/en/community/mailing-lists/
91. 2011 Call for grant proposals • Anyone can submit proposals • Grant size: ¥500,000 JPY (≒ $6400 USD) • Selection criteria – Impact on the productivity and performance of Ruby and its environment – Originality and creativity of the project – Feasibility of the project • Details: – http://www.ruby-assn.org/en/index.htm
92. Conclusion
93. Ruby's past • Ruby was created for fun • Ruby 1.8 is past
94. Ruby's present • Ruby is now mainstream • Ruby 1.9 is present
95. Ruby's future • Ruby 2.0 is future • You can change it! – http://redmine.ruby-lang.org/projects/ruby-trunk/ – http://www.ruby-lang.org/en/community/mailing-lists/
96. Thank you!
97. Any questions? :-)