+= 0.1
require ‘yarv’
require ‘syntax-1.9’
require ‘stdlib-1.9’
require ‘unicode’
Stephen Touset <stephen@touset.org>

Play Along at Home
$ svn export \\
http://svn.ruby-lang.org/repos/ruby/tags/v1_9_9_0 \\
ruby-1.9.0
$ cd ruby-1.9.0
$ ./configure --program-suffix 1.9
$ make
$ make test
$ chmod a+x bin/irb
$ PATH=. RUBYLIB=\"./lib\" bin/irb

YARV FTW
• Faster
• Less Memory
• Native threads*
• Fun Acronym
*concurrency of one

ruby 1.8 ruby 1.9 improvement
app_answer 0.460 0.146 68%
app_erb 1.655 1.646 0.5%
app_factorial 0.762 0.858 -13%
app_fib 5.572 1.530 73%
app_mandelbrot 2.034 0.848 58%
app_pentomino 92.811 50.778 45%
app_raise 1.984 2.474 -25%
app_strcat 1.414 1.113 21%
app_tak 8.306 2.083 75%
app_tarai 6.530 1.660 75%
app_uri 3.555 2.027 43%

≈38% faster
(62% as slow)
((twice-ish as fast))

Yet Another Meaningless Benchmark
(http://www.timestretch.com/FractalBenchmark.html)

The Image Below is
Not Photoshopped

...thus ending the
language wars once and
for all

Shiny New Syntax
• Lambda shortcut
• Implicit #call
• Literal hashes
• Block parameters
• Function parameter insanity
• Block local variables

lambda, v1.9
->

λ

_
/|

_
/|

->

λ
->
“I found lambda!”
- Matz

c = lambda {|a, b| [b, a] }
- becomes -
c = ->(a, b) { [b, a] }

Implicit #call
c = lambda {|a, b| [b, a] }
c.call(1, 2)
- becomes -
c = ->(a, b) { [b, a] }
c.(1,2)

Block Parameters
lambda {|a, b, c = 1, &d| d.call }
^
syntax error, unexpected '}' ...
- becomes -
->(a, b, c = 1, &d) { d.call }

laaaaame
lambda { yield }.call { puts ‘hi’ }
LocalJumpError: no block given
- becomes -
-> { yield }.() { puts ‘hi’ }
LocalJumpError: no block given

Literal Hashes
{ :a => 1, :b => 2,
:c => 3, :d => 4 }
- becomes -
{ a: 1, b: 2,
c: 3, d: 4 }

W...T...
def foo(a, b = 100, c)
puts “#{a} #{b} #{c}”
end
foo(3) # => ArgumentError
foo(3, 5) # => 3, 100, 5
foo(3, 4, 5) # => 3, 4, 5

...F
def bar(a, b = nil, *c, d)
end

Block Local Variables
i = Elephant.new
[1,2,3].map {|i| i * 2 }
i # => #<Elephant:0x3688b4>

stdlib.succ!
• send no longer calls private methods
• #methods and its siblings return symbols
• class variables are not inherited, now work
like class instance variables
(thus obsoleting my entire metaprogramming presentation)
• blocks passable to #[]
• enumerator love
• Oniguruma regexp engine

#tap that class
Passes an object to a block, then returns the object
(useful for call chaining)
‘foo’.tap(&:upcase!).tap {|s| s.gsub! /oo/, ‘u’ }

Wait, did I see that
correctly?
tap(&:upcase!)
^^

Enumerator Love
[1, 2, 3].cycle {|i| puts i } # loops forever puts-ing 1,2,3
[1, 2, 3].first(2) # => [1,2]
[1, 2, 3].map.with_index {|o,i| i} # => [0, 1, 2]
[1, 3, 4, 2].take {|i| i < 4 } # => [1, 3]
[1, 2, 3].reduce(:+1) # => 6

Ordered Hashes
h = { a: 1, b: 2, c: 3 }
h # => { a: 1, b: 2, c: 3 }
h.keys # => [ :a, :b, :c ]
h.values # => [ 1, 2, 3 ]

Encoded Strings
• No longer Enumerable
• String#bytes
• String#lines
• String#each_char
• “One-char-wide” String behavior

#!/usr/bin/ruby -w
# -*- coding: utf-8 -*-
open(filename, ‘r:utf-8’)
encodings = %w{ utf-8 utf-16
ascii-8bit euc-jp }

More Info
• Summary of Changes in 1.9
http://eigenclass.org/hiki/Changes+in+Ruby+1.9
• Mechanically Verified 1.9 Changelog
http://eigenclass.org/hiki/mechanically-verified-ruby19-changelog
• Matz’ RubyConf 2007 Keynote
http://rubyconf2007.confreaks.com/d2t1p8_keynote.html

exit(0)