class Class
def attr_accessor_with_history(attr_name)
attr_name = attr_name.to_s
# make sure it's a string
attr_reader attr_name
# create the attribute's
attr_reader attr_name+"_history" # create bar_history
class_eval %Q{
def #{attr_name}=(val)
@#{attr_name+"_history"}=[]
@#{attr_name+"_history"}.push(val)
@#{attr_name}=val
end
}
end
end
class Foo
attr_accessor_with_history :bar
end
我想制作 attr 访问器,它将记录数组中所有写入的历史记录,但问题出在 class_eval 中,数组每次都被初始化,因此它不保存旧值。
我应该做些什么改变?