Ruby7 OOP
Everything is Object 一切皆对象
a = "hello"
a.class # => String
b = 3.14
b.class # => Float
c = %w[pear cat horse]
c.class # => Array
Instance Method & Instance Attribute 实例方法，实例属性
- Instance Method: 实例方法，成员方法，成员函数
- Instance Attribute: 实例变量，成员属性，属性(property)，使用@定义
# class
class User
def initialize name, age
@name = name
@age = age
end
# getter
def name
@name
end
def age
@age
end
end
user = User.new('Hello', 18)
puts user.name
puts user.age
# class
class User
def initialize name, age
@name = name
@age = age
end
# getter
def name
@name
end
def age
@age
end
# setter
def name= name
@name = name
end
def age= age
@age = age
end
end
user = User.new('Hello', 18)
puts user.name
puts user.age
puts '-' * 30
user.name = 'hello 2'
user.age = 20
puts user.name
puts user.age
# class, attr_reader, attr_writer
class User
attr_reader :name
attr_reader :age
attr_writer :name
attr_writer :age
def initialize name, age
@name = name
@age = age
end
end
user = User.new('Hello', 18)
puts user.name
puts user.age
puts '-' * 30
user.name = 'hello 2'
user.age = 20
puts user.name
puts user.age
# class, method
class User
attr_accessor :name
attr_accessor :age
def initialize name, age
@name = name
@age = age
end
def say_hi
puts "hello #{@name}, i am #{@age}"
end
end
user = User.new('Hello', 18)
user.say_hi
Class Method & Class Variable 类方法，类变量
- Class Method:类方法，静态方法
- Class Variable:类变量, 使用@@定义
# class, method
class User
attr_accessor :name
attr_accessor :age
@@counter = 0
def initialize name, age
@name = name
@age = age
@@counter += 1
end
def say_hi
puts "hello #{@name}, i am #{@age}"
end
def self.get_counter
@@counter
end
end
puts User.get_counter
user = User.new('Hello', 18)
user.say_hi
puts User.get_counter
Access Control 访问控制
- public
- protected
- private
# class, method
class User
attr_accessor :name
attr_accessor :age
def initialize name, age
@name = name
@age = age
end
def say_hello
puts "hello..."
say_hi
say_hey
end
def say_hi
puts "hello #{@name}, i am #{@age}"
end
def say_hey
puts "hey, i am #{@name}"
end
protected :say_hi, :say_hey
end
user = User.new('Hello', 18)
user.say_hello
Dynamic Ruby 动态特性
User内幕
# attr_accessor 方法从哪里来的？
class User
# ...
end
User.class # => class
# Class.attr_accessor 背后的秘密
# define_method
# attr_accessor, define_method
define_method :hello do
puts "hello world"
end
hello
自己实现 attr_accessor
# define_method
class User
# attr_accessor :name
# attr_accessor :age
def self.setup_accessor var
define_method var do
instance_variable_get "@#{var}"
end
define_method "#{var}=" do |value|
instance_variable_set "@#{var}", value
end
end
setup_accessor :name
setup_accessor :age
def initialize name,age
@name = name
@age = age
end
end
user = User.new "hello", 18
puts user.name
puts '-' * 30
user.name = "hello 2"
puts user.name
