无法在instance_eval中调用* method = * type方法

Question

请考虑以下代码：

class Student
  attr_accessor :age, :gender, :school

  def explicit_school_setter
    @school = "Some School"
  end
end

bob = Student.new

bob.age = 16
bob.gender = :male

bob.instance_eval { school = :bvb } # ? Why is this not invoking the setter?

bob.age # => 16
bob.gender # => :male
bob.school # => nil

bob.instance_eval { explicit_school_setter }

bob.school # => "Some School"

bob.school = "Another School"

bob.school # => "Another School"

为什么setter无法在instance_eval块中运行？

Answer 1

当您致电school = :bvb时，您正在创建一个本地变量。将其更改为self.school = :bvb，您就完成了。

Answer 2

D @school而不是下面的学校，如下所示

bob.instance_eval { @school = :bvb }