ruby无法保护@变量么？

Question

看到一个例子，是有这个问题还是我理解不到位呢？

class LoadPaths
  # ...

  def initialize
    @paths = []
  end
  def push(*paths)
    @paths.push(*paths)
  end
  def inspect
    p @paths
  end
end

a = LoadPaths.new
x = a.push(1)
x.push 2
a.inspect

Answer 1

Instance methods operate instance variables, what’s the problem?

Answer 2

There is no problem at all.
What tends to cause problems is this:

class A

  def count
    @count ||= 0
    @count += 1
  end
end

a = A.new
a.count # => 1
a.instance_variable_set(:@count, 10)
a.count # => 11

Among theminstance_variable_setyou can modify the instance variables within the object ~ ~
Of course, it can also be understood as the power of Ruby!!!