使用和不使用self的类方法调用Ruby类方法之间有什么区别吗？

I am little bit curious about to know that, is there any difference between below two approaches?

我有点好奇要知道，以下两种方法之间有什么区别吗？

Calling class method with in class method using self

使用self在类方法中调用类方法
```
class Test
  def self.foo
   puts 'Welcome to ruby'
  end

 def self.bar
  self.foo
 end

end
```
Test.bar # Welcome to ruby

Test.bar＃欢迎来到红宝石
Calling class method with in class method without self

在没有self的类方法中调用类方法
```
class Test
  def self.foo
   puts 'Welcome to ruby'
  end

 def self.bar
  foo
 end

end
```
Test.bar # Welcome to ruby

Test.bar＃欢迎来到红宝石

1 个解决方案

#1

Yes, there is a difference. But not in your example. But if foo was a private class method, then your first version would raise an exception, because you call foo with an explicit receiver:

是，有一点不同。但不是在你的例子中。但是如果foo是一个私有类方法，那么你的第一个版本会引发异常，因为你用一个显式接收器调用foo：

class Test
  def self.foo
    puts 'Welcome to ruby'
  end
  private_class_method :foo

  def self.bar
    self.foo
  end
end

Test.bar
#=> NoMethodError: private method `foo' called for Test:Class

But the second version would still work:

但第二个版本仍然有效：

class Test
  def self.foo
    puts 'Welcome to ruby'
  end
  private_class_method :foo

  def self.bar
    foo
  end
end

Test.bar
#=> "Welcome to ruby"

#1