Feature #17155: Add a Diggable mixin

• Status: Open
• Assignee: -
• Target version: -

[janfri (Jan Friedrich)]

Ruby 2.3 introduced the #dig method as a general way to access elements in deep structures. Initially it was implemented only for Array and Hash. In the meanwhile also the classes Struct, OpenStruct and Set have a #dig method. There is also a proposal to implement #dig for Thread.

In my development I have own classes which have a #[] method implemented and are also candidates for a #dig method. But implementing #dig isn't so trivial as it seems: you have to handle some corner cases. This is the intention for my proposal: Add a Diggable mixin to Ruby (core or stdlib). A simple implementation of it could be something like this:

module Diggable

 def dig *args
   a = args.shift
   o = self[a]
   return o if args.empty? || o.nil?
   o.send :dig, *args
 end

end

So you could simply include Diggable to any class which implements #[], and you would get a #dig method for free. Like Comparable or Enumerable for which you have to implement #<=> respectively #each and get other methods implemented in this mixins.

[janfri (Jan Friedrich)]

• Description updated (diff)