Ruby中的终结器：是否有一个等价于__“破坏”；来自PHP？
在PHP类中，解析器处理Ruby中的终结器：是否有一个等价于__“破坏”；来自PHP？,ruby,destructor,finalizer,Ruby,Destructor,Finalizer,在PHP类中，解析器处理\uu构造和\uu析构函数方法来实例化实例并在脚本退出或使用unset时销毁它。扩展类时，只需使用parent:：u-construct和parent:：u-destruct来运行可能需要在扩展的类上运行的任何清理代码 现在，在一个表示DB数据并帮助您操作该数据的类的上下文中，我认为可以使用\uu destruct方法将当前值与从DB获取的原始值进行比较，并在必要时进行更新（在某些情况下，只要主键值不能更改，就始终执行更新） 这种方法的主要优点是，只需根据需要快速操作类变
\uu构造\uu析构函数parent:：u-constructparent:：u-destruct\uu destructparent:：\u constructsuperObjectSpace。为Ruby类定义\u finalizefinalize父级：：\u destructfinalize谢谢正如pst在他的评论中指出的那样，ruby不需要析构函数。只需将所有引用变量设置为null（ref=nil），该对象就会被垃圾收集删除。您无法确切知道它的garbace何时被收集（删除）。此外，您可以（我不建议这样做）编写一个在实际删除该对象之前运行的过程
ObjectSpace.define_finalizer(self, self.class.method(:finalize).to_proc)
不，Ruby与PHP
\uuu destructObjectSpace.define\u finalizerObjectSpace.Unfine\u finalizerselfGC.startrequire 'forwardable'
require 'pstore'
# Create a database of people's ages.
People = PStore.new('people.pstore')
People.transaction do
People['Alice'] = 20
People['Bob'] = 30
People['Carl'] = 40
People['David'] = 50
People['Eve'] = 60
end
# Shows people in database. This can show old values if someone
# forgot to update the database!
def show_people(heading)
People.transaction(true) do
puts heading
%w[Alice Bob Carl David Eve].each do |name|
puts " #{name} is #{People[name]} years old."
end
end
end
show_people("Before birthdays:")
# This is a person in the database. You can change his or her age,
# but the database is only updated when you call #update or by this
# object's finalizer.
class Person
# We need a PersonStruct for the finalizer, because Ruby destroys
# the Person before calling the finalizer.
PersonStruct = Struct.new(:name, :age, :oage)
class PersonStruct
def update(_)
s = self
if s.age != s.oage
People.transaction { People[s.name] = s.oage = s.age }
end
end
end
private_constant :PersonStruct
# Delegate name (r) and age (rw) to the PersonStruct.
extend Forwardable
def_delegators(:@struct, :name, :age, :age=)
# Find a person in the database.
def initialize(name)
age = People.transaction(true) { People[name] }
@struct = PersonStruct.new(name, age, age)
ObjectSpace.define_finalizer(self, @struct.method(:update))
end
# Update this person in the database.
def update
@struct.update(nil)
end
end
# Now give everyone some birthdays.
Person.new('Alice').age += 2
Person.new('Bob').age += 1
Person.new('Carl').age += 1
Person.new('David').age += 1
Person.new('Eve').age += 2
# I forgot to keep references to the Person objects and call
# Person#update. Now I try to run the finalizers.
GC.start
# Did the database get updated?
show_people("After birthdays:")
Before birthdays:
Alice is 20 years old.
Bob is 30 years old.
Carl is 40 years old.
David is 50 years old.
Eve is 60 years old.
After birthdays:
Alice is 22 years old.
Bob is 31 years old.
Carl is 41 years old.
David is 51 years old.
Eve is 60 years old.
我把Eve的年龄增加了2岁，但在检查数据库之前没有更新。解释Ruby的C代码可能留下了对
Person.new（'Eve'）的引用context.Update（objectGraph）object.Save