Ruby 1.9 changes, cherry picked

In this post I look at some hand-picked changes in ruby 1.9 including new features and deprecations. Of course you can check the full changelog anytime at the main Ruby Language Site.

Ruby 1.9 brought forth some very nice and important changes which have been refined in v1.9.1 and v1.9.2. Naturally upgrades come with a cost: some of the new features might/will break compatibility with old codes and solutions. I’ll show you the most important things to look out for and also some of the awesomeness of this new version of ruby.

Some of the most important improvements in ruby 1.9

• Much better threading – performance and tools are superior to ruby 1.8. Read more about threads and fibers at Paul Barry’s blog.
• Unicode support, finally. Also a brand new encoding engine has been added. There’s a very informative blog post about this on Yehuda Katz’s blog.
• The interpreter’s performance had been vastly improved. Check out the (v1.9.0) benchmark.
• Rubygems is now integrated into ‘ruby’ itself.

Let’s look at the main incompatibilites that can break your code

• The shiny new String class.
• Literal Hash constructor has changed.
  • {“a”, “b”} no longer makes a Hash but a nice syntax error. You have to use {“a” => “b”} or {:a => “b”} or  {a: “b”}

Now for the other important changes and upgrades

Changes in the Hash class

• Hash finally preserves insertion order
  • Ruby 1.8
    
    ^?View Code RUBY

    hash = {:a=> 'A', :b=>'B', :c=>'C', :d=>'D'} hash.keys ====> [:b, :c, :d, :a] hash.values ====> ["B", "C", "D", "A"]

  • Ruby 1.9
    
    ^?View Code RUBY

    hash = {:a=> 'A', :b=>'B', :c=>'C', :d=>'D'} hash.keys ====> [:a, :b, :c, :d] hash.values ====> ["A", "B", "C", "D"]

• Hash#to_s behaves much nicer
  • Ruby 1.8
    
    ^?View Code RUBY

    hash = {:a=> 1, :b=>2, :c=>3, :d=>4} hash.to_s ====> "b2c3d4a1"

  • Ruby 1.9
    
    ^?View Code RUBY

    hash = {:a=> 1, :b=>2, :c=>3, :d=>4} hash.to_s ====> "{:a=>1, :b=>2, :c=>3, :d=>4}"

• Hash#select now returns a hash, not an array
  • Ruby 1.8
    
    ^?View Code RUBY

    hash = {:a=> 1, :b=>2, :c=>3, :d=>4} hash.select{|k,v| k == :c } ====> [[:c, 3]]

  • Ruby 1.9
    
    ^?View Code RUBY

    hash = {:a=> 1, :b=>2, :c=>3, :d=>4} hash.select{|k,v| k == :c } ====> {:c=>3}

String changes

• Single character strings
  • Ruby 1.8
    
    ^?View Code RUBY

    irb(main):001:0> ?c => 99 irb(main):001:0> "cat"[1] => 97

  • Ruby 1.9
    
    ^?View Code RUBY

    irb(main):001:0> ?c => "c" irb(main):001:0> "cat"[1] => "a"

• Encoding, encoding, encoding
  • All strings have an additional chunk of info attached: Encoding
    
    ^?View Code RUBY

    ruby-1.9.2-p136 :003 > "whatever".encoding => #<Encoding:UTF-8> ruby-1.9.2-p136 :004 > "whatever".encoding.name => "UTF-8"

  • String#size takes encoding into account – returns the encoded character count
    
    ^?View Code RUBY

    puts utf8_string.size # >> 6 puts latin1_string.size # >> 6

  • You can get the raw datasize
    
    ^?View Code RUBY

    puts utf8_string.bytesize # >> 8 puts latin1_string.bytesize # >> 6

  • Indexed access is by encoded data – characters, not bytes
    
    ^?View Code RUBY

    puts utf8_string[2..4] # >> sum puts latin1_string[2..4] # >> sum

  • You can change encoding by force but it doesn’t convert the data
    
    ^?View Code RUBY

    my_string = "Whatever" puts my_string.encoding.name # >> US-ASCII my_string.force_encoding("UTF-8") puts my_string.encoding.name # >> UTF-8   # changing the encoding doesn't convert the data though! latin1_string.force_encoding("UTF-8") puts latin1_string.encoding.name # >> UTF-8 puts latin1_string.bytesize # >> 6 puts latin1_string.valid_encoding? # >> false latin1_string =~ /AR/ # !> ArgumentError: invalid byte sequence in UTF-8

  • You can re-encode a string to ‘fix’ the above ‘error’
    
    ^?View Code RUBY

    transcoded_utf8_string= latin1_string.encode("UTF-8") puts transcoded_utf8_string.valid_encoding? # >> true

  • Iterators have changed as String is not Enumerable anymore
    
    ^?View Code RUBY

    #Use each_byte, each_char or each_codepoint   utf8_resume.each_byte do |byte| puts byte end # >> 82 # >> 195 # >> 169 # >> 115 # >> 117 # >> 109 # >> 195 # >> 169   utf8_resume.each_char do |char| puts char end # >> R # >> é # >> s # >> u # >> m # >> é   utf8_resume.each_codepoint do |codepoint| puts codepoint end # >> 82 # >> 233 # >> 115 # >> 117 # >> 109 # >> 233   # if you need custom processing, you can get the enumerators with bytes, chars, lines and codepoints   p utf8_resume.bytes.first(3) # >> [82, 195, 169] p utf8_resume.chars.find { |char| char.bytesize > 1 } # >> "é" p utf8_resume.codepoints.to_a # >> [82, 233, 115, 117, 109, 233] p utf8_resume.lines.map { |line| line.reverse } # >> ["émuséR"]

Block variables now shadow local variables

#Ruby 1.9
 
irb(main):001:0> i=0; [1,2,3].each {|i|}; i
=> 0
irb(main):002:0> i=0; for i in [1,2,3]; end; i
=> 3
 
#Ruby 1.8.6
 
irb(main):001:0> i=0; [1,2,3].each {|i|}; i
=> 3

tr and Regexp are Unicode-compatible

You can now specify source file encoding

Basic

# coding: utf-8
Emacs

# -*- encoding: utf-8 -*-
Shebang

#!/usr/local/rubybook/bin/ruby
# encoding: utf-8

Inject methods

#Ruby 1.9
 
[1,2].inject(:+)
 
#Ruby 1.8.6
 
[1,2].inject {|a,b| a+b}

Lambda shorthand syntax

#Ruby 1.9
 
p = -> a,b,c {a+b+c}
puts p.(1,2,3)
puts p[1,2,3]
 
#Ruby 1.8.6
 
p = lambda {|a,b,c| a+b+c}
puts p.call(1,2,3)

Complex numbers

#Ruby 1.9
 
Complex(3,4) == 3 + 4.im

Multi-splat

# This will work on both Ruby 1.8 and 1.9
a, b, c = *[1, 2], 3
 
# This will fail on 1.8, but work on 1.9
a, b, c = 1, *[2, 3]
 
# Even this will work on 1.9, but not 1.8
a, b, c, d, e, f = *[1, 2], 3, *[4, 5]

Blocks now can accept block arguments

define_method(:answer) { |&b| b.call(42) }

In this post I look at some hand-picked changes in ruby 1.9 including new features and deprecations. Of course you can check the full changelog anytime at the main Ruby Language Site. Ruby 1.9 brought forth some very nice and important changes which have been refined in v1.9.1 and v1.9.2. Naturally upgrades come with a cost: some of the new features might/will break compatibility with old codes and solutions. I'll show you the most important things to look out for and also some of the awesomeness of this new version of ruby. Some of the most important improvements in ruby 1.9 Much better threading - performance and tools are superior to ruby 1.8. Read more about threads and fibers at Paul Barry's blog. Unicode support, finally. Also a brand new encoding engine has been added. There's a very informative blog post about this on Yehuda Katz's blog. The interpreter's performance had been vastly improved. Check out the (v1.9.0) benchmark. Rubygems is now integrated into 'ruby' itself. Let's look at the main incompatibilites that can break your code The shiny new String class. Literal Hash constructor has changed. {"a", "b"} no longer makes a Hash but a nice syntax error. You have to use {"a" => "b"} or {:a => "b"} or  {a: "b"} Now for the other important changes and upgrades Changes in the Hash class Hash finally preserves insertion order Ruby 1.8 hash = {:a=> 'A', :b=>'B', :c=>'C', :d=>'D'} hash.keys ====> [:b, :c, :d, :a] hash.values ====> ["B", "C", "D", "A"] Ruby 1.9 hash = {:a=> 'A', :b=>'B', :c=>'C', :d=>'D'} hash.keys ====> [:a, :b, :c, :d] hash.values ====> ["A", "B", "C", "D"] Hash#to_s behaves much nicer Ruby 1.8 hash = {:a=> 1, :b=>2, :c=>3, :d=>4} hash.to_s ====> "b2c3d4a1" Ruby 1.9 hash = {:a=> 1, :b=>2, :c=>3, :d=>4} hash.to_s ====> "{:a=>1, :b=>2, :c=>3, :d=>4}" Hash#select now returns a hash, not an array Ruby 1.8 hash = {:a=> 1, :b=>2, :c=>3, :d=>4} hash.select{|k,v| k == :c } ====> [[:c, 3]] Ruby 1.9 hash = {:a=> 1, :b=>2, :c=>3, :d=>4} hash.select{|k,v| k == :c } ====> {:c=>3} String changes Single character strings Ruby 1.8 irb(main):001:0> ?c => 99 irb(main):001:0> "cat"[1] => 97 Ruby 1.9 irb(main):001:0> ?c => "c" irb(main):001:0> "cat"[1] => "a" Encoding, encoding, encoding All strings have an additional chunk of info attached: Encoding ruby-1.9.2-p136 :003 > "whatever".encoding => # ruby-1.9.2-p136 :004 > "whatever".encoding.name => "UTF-8" String#size takes encoding into account - returns the encoded character count puts utf8_string.size # >> 6 puts latin1_string.size # >> 6 You can get the raw datasize puts utf8_string.bytesize # >> 8 puts latin1_string.bytesize # >> 6 Indexed access is by encoded data - characters, not bytes puts utf8_string[2..4] # >> sum puts latin1_string[2..4] # >> sum You can change encoding by force but it doesn't convert the data my_string = "Whatever" puts my_string.encoding.name # >> US-ASCII my_string.force_encoding("UTF-8") puts my_string.encoding.name # >> UTF-8 # changing the encoding doesn't convert the data though! latin1_string.force_encoding("UTF-8") puts latin1_string.encoding.name # >> UTF-8 puts latin1_string.bytesize # >> 6 puts latin1_string.valid_encoding? # >> false latin1_string =~ /AR/ # !> ArgumentError: invalid byte sequence in UTF-8 You can re-encode a string to 'fix' the above 'error' transcoded_utf8_string= latin1_string.encode("UTF-8") puts transcoded_utf8_string.valid_encoding? # >> true Iterators have changed as String is not Enumerable anymore #Use each_byte, each_char or each_codepoint utf8_resume.each_byte do |byte| puts byte end # >> 82 # >> 195 # >> 169 # >> 115 # >> 117 # >> 109 # >> 195 # >> 169 utf8_resume.each_char do |char| puts char end # >> R # >> é # >> s # >> u # >> m # >> é utf8_resume.each_codepoint do |codepoint| puts codepoint end # >> 82 # >> 233 # >> 115 # >> 117 # >> 109 # >> 233 # if you need custom processing, you can get the enumerators with bytes, chars, lines and codepoints p utf8_resume.bytes.first(3) # >> [82, 195, 169] p utf8_resume.chars.find { |char| char.bytesize > 1 } # >> "é" p utf8_resume.codepoints.to_a # >> [82, 233, 115, 117, 109, 233] p utf8_resume.lines.map { |line| line.reverse } # >> ["émuséR"] Block variables now shadow local variables #Ruby 1.9 irb(main):001:0> i=0; [1,2,3].each {|i|}; i => 0 irb(main):002:0> i=0; for i in [1,2,3]; end; i => 3 #Ruby 1.8.6 irb(main):001:0> i=0; [1,2,3].each {|i|}; i => 3 tr and Regexp are Unicode-compatible You can now specify source file encoding Basic # coding: utf-8 Emacs # -*- encoding: utf-8 -*- Shebang #!/usr/local/rubybook/bin/ruby # encoding: utf-8 Inject methods #Ruby 1.9 [1,2].inject(:+) #Ruby 1.8.6 [1,2].inject {|a,b| a+b} Lambda shorthand syntax #Ruby 1.9 p = -> a,b,c {a+b+c} puts p.(1,2,3) puts p[1,2,3] #Ruby 1.8.6 p = lambda {|a,b,c| a+b+c} puts p.call(1,2,3) Complex numbers #Ruby 1.9 Complex(3,4) == 3 + 4.im Multi-splat # This will work on both Ruby 1.8 and 1.9 a, b, c = *[1, 2], 3 # This will fail on 1.8, but work on 1.9 a, b, c = 1, *[2, 3] # Even this will work on 1.9, but not 1.8 a, b, c, d, e, f = *[1, 2], 3, *[4, 5] Blocks now can accept block arguments define_method(:answer) { |&b| b.call(42) }

Tagged as: 1.8, 1.9, changes, comparison, improvements, performance, ruby