Question

我上课了枚举。

如何仅限制3个对象的访问权限？

class My
 include Enumerable
 def initialize(*s)
  @s = s
 end
 def each(&blok)
  @s.each(&blok)
 end
end

这没关系，只有字符串和整数以及我的

 b = Array.new(3)
 m = My.new
 my = MySuperObject("normal","slowly",1,m)

这不行，双，数组

 my = MySuperObject(1.5,"ok",b,m)

Answer 1

你的意思是这样吗？

require 'forwardable'
class MySuperObject
  extend Forwardable
  def_delegators :@target, *Enumerable.instance_methods
  def initialize(*args)
    if args.any? { |arg| ![String,Fixnum].include?(arg.class) }
       #alternatively as @tadman pointed out you could use
       #args.all? { |arg| arg.is_a?(String) || arg.is_a?(Fixnum) }  
       raise ArgumentError, 'Must be a String or Integer'
    else
       #what ever you need to do here
       @target = args
    end 
  end
end

然后

MySuperObject.new(12,"String")
#=> #<MySuperObject:0x2c1e568>

MySuperObject.new(12.4,"String")
#ArgumentError: Must be a String or Integer

关于这不是一个没有这样的东西的Enumerable类的抱怨吗（Enumerable是一些类中包含的模块）我已经更新了我的答案，将所有可枚举方法委托给@target。

MySuperObject.instance_methods.sort - Object.methods
#=> [:all?, :any?, :chunk, :collect, :collect_concat, :count, :cycle, 
     :detect, :drop, :drop_while, :each_cons, :each_entry, 
     :each_slice, :each_with_index, :each_with_object, :entries, 
     :find, :find_all,:find_index, :first, :flat_map, :grep, 
     :group_by, :inject, :map, :max, :max_by, :member?, :min, 
     :min_by, :minmax, :minmax_by, :none?, :one?, :partition,:reduce, 
     :reject, :reverse_each, :select, :slice_before, :sort, :sort_by, 
     :take, :take_while, :to_a, :zip]

请注意rubyists喜欢鸭子打字和限制输入这样做应该有充分的理由这样做，因为它打破了这个概念。

如何使用特定对象创建Enumerable

1 个答案: