Ruby属性与方法 #

class Person
  attr_reader :name

  def initialize(name)
    @name = name
  end
end

person = Person.new("Ruby")
person.name
person.name = "Rails"

class Person
  attr_writer :name

  def initialize(name)
    @name = name
  end

  def greet
    "Hello, #{@name}"
  end
end

person = Person.new("Ruby")
person.name = "Rails"
person.greet
person.name

class Person
  attr_accessor :name, :age

  def initialize(name, age)
    @name = name
    @age = age
  end
end

person = Person.new("Ruby", 30)
person.name
person.name = "Rails"
person.age
person.age = 31

class Person
  def initialize(name)
    @name = name
  end

  def name
    @name
  end

  def name=(new_name)
    @name = new_name
  end
end

class Person
  def initialize(name)
    @name = name
  end

  def name
    @name.upcase
  end

  def name=(new_name)
    @name = new_name.strip
  end
end

person = Person.new("  Ruby  ")
person.name
person.name = "  Rails  "
person.name

class Person
  def greet
    "Hello!"
  end
end

person = Person.new
person.greet

class Person
  def self.create
    Person.new
  end

  class << self
    def default
      Person.new
    end
  end
end

Person.create
Person.default

module Helper
  def self.utility
    "Utility method"
  end

  module_function

  def exported
    "Exported method"
  end
end

Helper.utility
Helper.exported

class Person
  def greet
    "Hello!"
  end
end

person = Person.new
person.greet

class Person
  def initialize(name)
    @name = name
  end

  def introduce
    "Hello, I'm #{name}"
  end

  private

  def name
    @name
  end
end

person = Person.new("Ruby")
person.introduce
person.name

class Person
  def initialize(age)
    @age = age
  end

  def older_than?(other)
    age > other.age
  end

  protected

  def age
    @age
  end
end

alice = Person.new(30)
bob = Person.new(25)
alice.older_than?(bob)
alice.age

class Example
  def public_method
  end

  private :public_method

  def another_public
  end

  private

  def private_method_1
  end

  def private_method_2
  end

  public :another_public
end

class Counter
  @@count = 0

  def initialize
    @@count += 1
  end

  def self.count
    @@count
  end
end

Counter.new
Counter.new
Counter.count

class Counter
  @count = 0

  def initialize
    self.class.count += 1
  end

  class << self
    attr_accessor :count
  end
end

Counter.count = 0
Counter.new
Counter.new
Counter.count

class Parent
  @@class_var = "parent"
  @class_instance_var = "parent"
end

class Child < Parent
  @@class_var = "child"
  @class_instance_var = "child"
end

Parent.class_variable_get(:@@class_var)
Child.class_variable_get(:@@class_var)

Parent.instance_variable_get(:@class_instance_var)
Child.instance_variable_get(:@class_instance_var)

class User
  def initialize(email, password)
    @email = email
    @password = encrypt(password)
  end

  def authenticate(password)
    @password == encrypt(password)
  end

  private

  def encrypt(text)
    Digest::SHA256.hexdigest(text)
  end
end

class Employee
  def initialize(salary)
    @salary = salary
  end

  def higher_paid_than?(other)
    salary > other.salary
  end

  protected

  def salary
    @salary
  end
end

class Configuration
  class << self
    attr_accessor :api_key, :timeout, :debug

    def configure
      yield self
    end

    def reset
      @api_key = nil
      @timeout = 30
      @debug = false
    end
  end

  reset
end

Configuration.configure do |config|
  config.api_key = "secret"
  config.timeout = 60
  config.debug = true
end

class Person
  attr_reader :name, :age

  def name=(value)
    raise ArgumentError, "Name cannot be empty" if value.nil? || value.empty?
    @name = value
  end

  def age=(value)
    raise ArgumentError, "Age must be positive" if value.nil? || value < 0
    @age = value
  end
end

person = Person.new
person.name = "Ruby"
person.age = 30

class Person
  def initialize(first_name, last_name)
    @first_name = first_name
    @last_name = last_name
  end

  def full_name
    "#{@first_name} #{@last_name}"
  end

  def full_name=(name)
    @first_name, @last_name = name.split(" ", 2)
  end
end

person = Person.new("Ruby", "Rails")
person.full_name
person.full_name = "New Name"
person.full_name