Footing Brainstorm

better_hash.rb

class BetterHash < Footing

  def filter!(keys, replacement: "[FILTERED]")
    should_replace = lambda do |key|
      replace = false
      keys.each do |k|
        break if replace
        replace = k.is_a?(Regexp) ? key.to_s =~ k : key.to_s == k.to_s
      end
      replace
    end

    each do |key, value|
      if value.is_a?(::Hash)
        value.filter!(keys, replacement: replacement)
      elsif value.is_a?(Enumerable)
        value.each do |val|
          if val.is_a?(::Hash)
            value.filter!(keys, replacement: replacement)
          end
        end
      else
        value = replacement if should_replace.call(key)
        self[key] = value
      end
    end

    self
  end

end

footing.rb

require 'delegate'

class Footing < SimpleDelegator

  class << self

    def copy(o)
      Marshal.load Marshal.dump(o)
    end

  end

  def initialize(o, copy: true)
    o = self.class.copy(o) if copy
    super(o)
  end

  def inner_object
    __getobj__
  end

end

usage.md

data = { name: "Joe", password: "secret" }
copy = BetterHash.new(data)
copy.filter!([:password])
copy.inner_object # => {:name=>"Joe", :password=>"[FILTERED]"}