如何重载 each 来建立所需的顺序

发布于 2024-12-29 23:05:41 字数 840 浏览 0 评论 0原文

这类似于按顺序重载每个方法中发布的问题，但是区别在于我希望支持所有关联的可枚举方法而无需重新定义。

使用 mixin，如何重写 each 以及由 enumerable 提供的所有关联方法，而不重新定义它们中的每一个。例如：

module Ordering
   def self.included base
       base.class_eval do
           alias_method :old_each,:each

           def each *args,&block
               reverse.old_each(*args,&block) # sample: just reverse std order
           end
       end
   end
end

class OrderedArray < Array
   include Ordering
end

a=OrderedArray.new [1,2,3]
a.each{|_| p _} # works nicely
p a.collect     # fails!

生成：

3
2
1
[1, 2, 3]

重新定义 each 似乎没有重新定义 collect!

原文

This is similar to question posted in Overload each method with order but with the difference that I would like to have all associated enumerable methods supported without redefinition.

Using a mixin, how do I override each and all associated methods supplied by enumerable without redefining each of them. For example:

module Ordering
   def self.included base
       base.class_eval do
           alias_method :old_each,:each

           def each *args,&block
               reverse.old_each(*args,&block) # sample: just reverse std order
           end
       end
   end
end

class OrderedArray < Array
   include Ordering
end

a=OrderedArray.new [1,2,3]
a.each{|_| p _} # works nicely
p a.collect     # fails!

generates: