RSpecではまるで自然言語（英語の文章）を書くかのように、振舞の定義（*_spec.rb)が書けます。プロダクトコードでも同様に英語の文法を意識して書くようにしてみたらどうなるでしょうか。Rubyを使って試してみました。

1. Programming Production Code
as if writing Natural Language
Kazuya NUMATA
@kaznum

2. Self-introduction
(Kazuya NUMATA)
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3. My favorite
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4. Agile

5. Communication with team members
including stakeholder
＆
Iterative Testing

6. Behavior Driven Development
BDD

7. Tools
to make BDD effective

8. • RSpec (Ruby)
• NSpec (.NET)
• CppSpec (C++)
• JBehave (Java)
• instinct (Java)
• PHPSpec (PHP)
• and more....

9. Question

10. Question
Have you ever experienced *Spec?
*Spec ？

11. RSpec example:
describe "A new chess board" do
before(:each) do
@board = Chess::Board.new
end
it "should have 32 pieces" do
@board.should have(32).pieces
end
end
D. Chelimsky. The RSpec Book
Section 13.7 Generated Descriptions

12. RSpec example:
describe "A new chess board" do
before(:each) do
@board = Chess::Board.new
end
it "should have 32 pieces" do
@board.should have(32).pieces
end
end
D. Chelimsky. The RSpec Book
Section 13.7 Generated Descriptions

13. RSpec example:
$ rspec -fd board_spec.rb
(Output is...)
A new chess board
should have 32 pieces
D. Chelimsky. The RSpec Book
Section 13.7 Generated Descriptions

14. It is just Natural Language!

15. �

16. The reality is that it’s hard for the Japanese.

17. Cucumber
( ）

18. Cucumber Example:
:
:
" " " "
" " " Cucumber"
" "
" Cucumber"
( ∀ )o sasata299's blog
http://blog.livedoor.jp/sasata299/archives/51278697.html

20. /Spec
Before
BDD
After Spec Spec
BDD

21. Before
BDD
After
BDD

22. ？

25. Uncle Bob
Complex fulcrumPoint = Complex.FromRealNumber(23.0);
is generally better than
Complex fulcrumPoint = new Complex(23.0);
Consider enforcing their use by making the corresponding constructors private.
（ ）

26. by Masayoshi Son

27. Person
name
true
false

28. Ruby Example: name 1
ex1
class Person
attr_accessor :name
def initialize(name = nil)
@name = name
end
end
shimada = Person.new(“Shimada”)
if shimada.name.split(//)[0] == “S”
puts “Match”
end

29. Ruby Example: name 1
ex2
class Person
attr_accessor :name
def initialize(name = nil)
@name = name
end
def has_a_name_that_begins_with?(expected)
@name.split(//)[0] == expected
end
end
shimada = Person.new(“Shimada”)
if shimada.has_a_name_that_begins_with?(“S”)
puts “Match”
end

30. Ruby Example: name 1
ex3
class Person
attr_accessor :name
def initialize(name = nil)
@name = name
end
def has_a_name_that_begins_with?(expected)
@name.split(//)[0] == expected
end
def method_missing(m, *args, &block)
if m.to_s =~ /has_(a|the)_name_(that|which)_begins_with?/
has_a_name_that_begins_with?(args)
else
super
end
end
end
shimada = Person.new(“Shimada”)
puts “Match” if shimada.has_a_name_that_begins_with?(“S”)
puts “Match” if shimada.has_the_name_that_begins_with?(“S”)
puts “Match” if shimada.has_a_name_which_begins_with?(“S”)
puts “Match” if shimada.has_the_name_which_begins_with?(“S”)

31. Ruby Example: name 1
ex4 name String
has_(a|the)_(.+)_(which|that)_begins_with?
Dynamic setter
undef Singleton Method
class Person
def initialize(args)
args.each do |key, value|
self.class.send(:attr_accessor, :"#{key}") unless instance_variables.include?(:"@#{key}")
instance_variable_set(:"@#{key}", value)
end
end
def self.undef_has_a_var_which_begins_with(var)
method_name = "has_a_#{var}_which_begins_with?"
send("undef_method", method_name) if method_defined? method_name
end
def self.define_has_a_var_which_begins_with(var)
method_name = "has_a_#{var}_which_begins_with?"
define_method(method_name) do |expectation|
value = instance_variable_get(:"@#{var}")
if value.is_a?(String)
value.split(//)[0].downcase == expectation.downcase
else
self.class.undef_has_a_var_which_begins_with(var)
method_missing(method_name.to_sym)
end
end
end
def method_missing(m, *args, &block)
if m.to_s =~ /has_(a|the)_(.+)_(which|that)_begins_with?/ &&
instance_variables.include?(:"@#{Regexp.last_match[2]}") &&
instance_variable_get(:"@#{Regexp.last_match[2]}").is_a?(String)
var_name = Regexp.last_match[2]
self.class.define_has_a_var_which_begins_with(var_name)
send("has_a_#{var_name}_which_begins_with?".to_sym, *args, &block)
else
super(m, *args, &block)
end
end
end
#### sample #####
shimada = Person.new(:name => "Shimada", :age => 18, :sex => :half, :fuga => "bababa")
p shimada.has_a_name_which_begins_with?("S") ? "Good" : "Suck"
p shimada.has_the_name_which_begins_with?("S") ? "Good" : "Suck"
shimada.name = 5
p shimada.has_the_name_which_begins_with?("5") ? "Good" : "Suck" #=> undefined method

33. if air_plane.is_created_by? :bowing
if he.is_eligible_to_get? reward
if selected_value.is_valid?
→
can_..., is_,

34. is does was did
module Kernel
def is(expected)
expected
end
alias_method :does, :is
alias_method :was, :is
alias_method :were, :is
alias_method :did, :is
# alias_method :do, :is × do
end
is air_plane.created_by?(bowing)
does [1,2,3].include?
is he.eligible_to_get?(bonus)
does [1,2,3].include?
is "h".included_in?("hello")
is she, nancy # ?

35. Conclusion & Impression
• Spec
•
•
• Receiver
Array#sort
• Ruby Standard Library if obj.instance_of?(exp) be
(Is Object#is Is#method_missing
self return...)
•
•
•

36. thank you :)