Ruby 1.9New in

Bruce Williams

Thanks for having me out to Boston.

(especially to Thoughtbot & Tammer for the couch surfing opportunity)

Bruce Williams

Language Geek

lojbanesperantoarabic

basque

spanish

german

russian

erlang

ruby perl

python

c

java

haskellocaml

io

self

smalltalk

objc

english

lisp c++

awkeiffel

2001...2005Rubyist

2005..2008:-) + $:-)

Open Source DeveloperRTeX, TuneUp, keyword_search, numerous Rails

plugins

A bunch of URLshttp://codefluency.com

http://github.com/bruce

http://fiveruns.com

http://twitter.com/wbruce

and 1.9?

YARV

1.9 is just like 1.7.Except completely

different.

1.8.61.8.51.8.4

1.8.31.8.21.8.1

1.8.01.6.81.6.71.6.21.6.1

1.6.01.5

1.71.9

1.6.41.6.51.6.3

Japan Beyond Japan “... on Rails” Expansion

‘00 ‘01 ‘02 ‘03 ‘04 ‘05 ‘06 ‘07 ‘08

(dev)

(dev)

(dev)

1.8.7

... 2.0

1.9.1

...

StableReleases

1.9.1 will be stable.

Expect it around Christmas.

Many new syntax and language features.

Not strictly backwards compatible to 1.8.

Better performance characteristics.

More bugs (it’s new!)

1.9

Many new syntax and language features.

Not strictly backwards compatible to 1.8.

Better performance characteristics.

More bugs (it’s new!)

Out of scope.

(I’m not psychic)

1.9

$ svn co http://svn.ruby-lang.org/repos/ruby/trunk ruby1.9$ cd ruby1.9$ autoconf$ ./configure --program-suffix=1.9$ make && sudo make install

Installing

From Subversion:

1.9.0:

http://www.ruby-lang.org/en/downloads/

$ git clone git://github.com/bruce/compare-1-9.git $ cd compare-1-9$ rake db:migrate$ ruby script/server

Comparison App

(use ruby 1.8!)

Standard Library Changes

soap, wsdl, base64, some rarely used, old libraries

rubygems, rake, json, ripper, probeprofiler, securerandom, HMAC digests

csv replaced by FasterCSV implementation

12

3

Risk FactorsMigration

Having good test coverage is very helpful when migrating code from 1.8 to 1.9.

<obligatory-testing-related-slide bdd-buzzword-compliant=”0”>

</obligatory-testing-related-slide>

Risk: Text Processing

Relying on $KCODE, String#[], or String internals. Parsers especially at risk.

? New encoding support, String#[] returns chr, not ord

Use new encoding conventions.Get familiar with String#ord and unpack(‘c*’).

Risk: Text Processing

"ruby"[0]# => 114

"ruby"[0]# => “r”

Ruby 1.9Ruby 1.8

"ruby".unpack('U*')# => [114, 117, 98, 121]

[0]"كلمات"# => 217 <= #"ك"

[0]"كلمات"

.unpack('U*')# => [1603, 1604, 1605, 1575, 1578]"كلمات"

Risk: Block Var Scope

Modifying variables outside the scope of a block with a block argument. “Clever” block tricks.

? Block variables are always local, and you get warnings when shadowing outer local variables

Modify the outer variable manually from insidethe block if needed. Stop being “clever.”

Risk: Block Var Scope

item = 12.upto(4) do |item| p itemend# Outputs:# 2# 3# 4item# => 4

item = 12.upto(4) do |item| p itemend# Outputs:# 2# 3# 4item# => 1

Ruby 1.9Ruby 1.8“clever”assignment

Shadowing.Still a bad idea. Use a different name.

d = 2->(;d) { d = 1 }.()d# => 2

d = 2-> { d = 1 }.()d# => 1

Ruby 1.9not declaring local

Risk: Block Var Scope

Ruby 1.9declaring local

changed the outer variable this didn’t, but you still get the shadowing warning.

Risk: Hash#select

?

Expecting an Array result from Hash#select, or capturing both key and value in a single block argument.

Hash#select now returns a ... Hash, and it’s arity-aware.

Check your loops on results from Hash#select.You may be able to remove some Hashre-creation code.

Risk: Hash Enumerations

Ruby 1.9Ruby 1.8conferences.select do |name, _| name == :lsrcend# => [[:lsrc, "Austin"]]

conferences.select do |name, _| name == :lsrcend# => {:lsrc=>"Austin"}

Hash#select returns a Hash. Yes!

Ruby 1.9Ruby 1.8conferences.select do |data| p dataend# [:lsrc, "Austin"]# [:scotland_on_rails, "Edinburgh"]# [:railsconf_europe, "Berlin"]

conferences.select do |data| p dataend# :lsrc# :scotland_on_rails# :railsconf_europe

conferences.select do |name, city| p [name, city]end# [:lsrc, "Austin"]# [:scotland_on_rails, "Edinburgh"]# [:railsconf_europe, "Berlin"]

warning: multiple values for a block parameter (2 for 1)

Risk: Hash EnumerationsArity matters with Hash#select.

Risk: Gems

The biggest obstacle to Ruby 1.9’s adoption is the sheer number of mostly working but essentially unmaintained gems that virtually everybody in the Ruby community depends on

Help!

- Sam Ruby

New Features

XL

Multilingualization(m17n)

There is one type of string, and the encoding is mutable

Strings don’t have #each (use #each_char, #each_line, etc)

The encoding is ‘lazy’ and can be set by probing with

String#ascii_only? and String#valid_encoding?. 

Various ways to set default encoding (commandline, magic comments)

# encoding: utf-8

String#[] now returns a String, not a Fixnum (use ord)

[:ASCII_8BIT, :Big5, :BIG5, :CP949, :EUC_JP, :EUC_KR, :EUC_TW, :GB18030, :GBK, :ISO_8859_1, :ISO_8859_2, :ISO_8859_3, :ISO_8859_4, :ISO_8859_5, :ISO_8859_6, :ISO_8859_7, :ISO_8859_8, :ISO_8859_9, :ISO_8859_10, :ISO_8859_11, :ISO_8859_13, :ISO_8859_14, :ISO_8859_15, :ISO_8859_16, :KOI8_R, :KOI8_U, :Shift_JIS, :SHIFT_JIS, :US_ASCII, :UTF_8, :UTF_16BE, :UTF_16LE, :UTF_32BE, :UTF_32LE, :Windows_1251, :WINDOWS_1251, :BINARY, :IBM437, :CP437, :IBM737, :CP737, :IBM775, :CP775, :CP850, :IBM850, :IBM852, :CP852, :IBM855, :CP855, :IBM857, :CP857, :IBM860, :CP860, :IBM861, :CP861, :IBM862, :CP862, :IBM863, :CP863, :IBM864, :CP864, :IBM865, :CP865, :IBM866, :CP866, :IBM869, :CP869, :Windows_1258, :WINDOWS_1258, :CP1258, :GB1988, :MacCentEuro, :MACCENTEURO, :MacCroatian, :MACCROATIAN, :MacCyrillic, :MACCYRILLIC, :MacGreek, :MACGREEK, :MacIceland, :MACICELAND, :MacRoman, :MACROMAN, :MacRomania, :MACROMANIA, :MacThai, :MACTHAI, :MacTurkish, :MACTURKISH, :MacUkraine, :MACUKRAINE, :CP950, :EucJP, :EUCJP, :EucJP_ms, :EUCJP_MS, :EUC_JP_MS, :CP51932, :EucKR, :EUCKR, :EucTW, :EUCTW, :EUC_CN, :EucCN, :EUCCN, :GB12345, :CP936, :ISO_2022_JP, :ISO2022_JP, :ISO_2022_JP_2, :ISO2022_JP2, :ISO8859_1, :Windows_1252, :WINDOWS_1252, :CP1252, :ISO8859_2, :Windows_1250, :WINDOWS_1250, :CP1250, :ISO8859_3, :ISO8859_4, :ISO8859_5, :ISO8859_6, :Windows_1256, :WINDOWS_1256, :CP1256, :ISO8859_7, :Windows_1253, :WINDOWS_1253, :CP1253, :ISO8859_8, :Windows_1255, :WINDOWS_1255, :CP1255, :ISO8859_9, :Windows_1254, :WINDOWS_1254, :CP1254, :ISO8859_10, :ISO8859_11, :TIS_620, :Windows_874, :WINDOWS_874, :CP874, :ISO8859_13, :Windows_1257, :WINDOWS_1257, :CP1257, :ISO8859_14, :ISO8859_15, :ISO8859_16, :CP878, :SJIS, :Windows_31J, :WINDOWS_31J, :CP932, :CsWindows31J, :CSWINDOWS31J, :MacJapanese, :MACJAPANESE, :MacJapan, :MACJAPAN, :ASCII, :ANSI_X3_4_1968, :UTF_7, :CP65000, :CP65001, :UCS_2BE, :UCS_4BE, :UCS_4LE, :CP1251]

Regular Expressions

Integrated the “Oniguruma” engine鬼車Same basic APIMuch better performanceSupport for encodingsExtended Syntax Look-ahead (?=), (?!), look-behind (?<), (?<!)

Named groups (?<>), backreferences, etc

"His name is Joe".match(/name is (?<name>\S+)/)[:name]# => "Joe"

Named Groups

MultilingualizationRead a file with File.read

File.read("input.txt").encoding# => #<Encoding:UTF-8>

File.read("input.txt", encoding: 'ascii-8bit').encoding# => #<Encoding:ASCII-8BIT>

result = File.open("input.txt", "r:euc-jp") do |f| f.readendresult.encoding# => #<Encoding:EUC-JP>result.valid_encoding?# => true

Read a file with File.open

EnumerableEnumerator built-in, returned from Enumerable methods (and those in Array, Dir, Hash, IO, Range, String or Struct that serve the same purposes). Added Enumerator#with_index

%w(Joe John Jack).map.with_index do |name, offset| "#{name} is #{offset + 1}"end# => ["Joe is #1", "John is #2", "Jack is #3"]

Map with Index

Enumerable

[1,2,3,4].reduce(:+)# => 10

[1,2,3,4].reduce(&:+)# => 10

Reduce (inject) SymbolorSymbol#to_proc

EnumerableNew Enumerable methods take, group_by, drop, min_by, max_by, count, and others.

array = [1, 2, 3, 4, 5]array.take(3)# => [1, 2, 3]array# => [1, 2, 3, 4, 5]

array = [1, 2, 3, 4, 5]array.drop(3)# => [4, 5]array# => [1, 2, 3, 4, 5]

Take Drop

Hash Changes

conferences = { lsrc: 'Austin', scotland_on_rails: 'Edinburgh'}conferences[:rubyconf] = 'Orlando'conferences.each do |name, city| p "#{name} is in #{city}"end# "lsrc is in Austin"# "scotland_on_rails is in Edinburgh"# "rubyconf is in Orlando"conferences.delete(:scotland_on_rails)conferences[:scotland_on_rails] = 'Edinburgh'conferences.each do |name, city| p "#{name} is in #{city}"end# "lsrc is in Austin"# "rubyconf is in Orlando"# "scotland_on_rails is in Edinburgh"

Insertion Order

thing = Thing.new.tap do |thing| thing.something = 1 thing.something_else = 2end

Object

Tap

{foo: 1, bar: 2}# => {:foo=>1, :bar=>2}

{foo: 1, 'bar' => 2, 'foo' => 3}# => {:foo=>1, "bar"=>2, "foo"=>3}

some_method "argument1", a: 1, b: 2

Symbol shortcut

You can mix forms

And leave it `open’

New Hash Literal

New Proc LiteralMore flexible

Not possible in { | | ... } style literals

m = ->(x, &b) { b.(x * 2) if b }m.(3) do |result| puts resultend# Output# 6

->(a, b=2) { a * b }.(3)# => 6

Passing blocks Default arguments

-> a = 1, b = 2, c, &d ; e { e = d.(a * b * c); e + 1 }.(3) { |p| p * 4 }# => 25

Can be Ugly as Hell

Don’t do this. Ruby isn’t Perl.!

Symbol Changes

Indexing into Comparing with a String

Added to_proc

Added =~, [] like String (to_s less needed), sortable

Object#methods, etc now return an array of symbols

:foo[1]# => "o"

:this === "this"# => true

ThreadsMoved to a native threading model.

A thread has mutex (GVL: Global VM Lock) can run. When thread scheduling, running thread release GVL. If running thread try blocking operation, this thread must release GVL and another thread can continue this flow. After blocking operation, thread must check interrupt (RUBY_VM_CHECK_INTS).

Every VM can run parallel.

Ruby threads are scheduled by OS thread scheduler.

From thread.c (“model 2”):

Fibers

http://pragdave.blogs.pragprog.com/pragdave/2007/12/pipelines-using.html

http://www.davidflanagan.com/blog/2007_08.html

InfoQ, others...

“Semi-coroutines.” Think of them as lightweight user threads with manual scheduling.

Revactor

NeverBlock

Questions?

Thank You.bruce@codefluency.com

http://twitter.com/wbruce