DelegateTo

delegate_to.rb

class DelegateTo < BasicObject
  include ::Kernel

  def initialize(object)
    @delegate_to = object
  end

  def inspect
    "#{self.class.inspect}[#{@delegate_to}]"
  end

  class << self
    alias_method :[], :new

    def to_proc
      method(:new).to_proc
    end

    def const_missing(name)
      ::Object.const_get(name)
    end
  end
end

def DelegateTo(target, &block)
  comparisons = [:=~, :!~, :===, :<=>, :eql?, :hash]

  Class.new(::DelegateTo) do
    delegate_missing_to target
    delegate target, to: :@delegate_to
    delegate :to_s, *comparisons, to: target

    define_method(:==) do |other|
      return true if other.equal?(self)
      public_send(target) == other
    end

    define_method(:!=) do |other|
      return false if other.equal?(self)
      public_send(target) != other
    end

    define_singleton_method(:inspect) do
      name || "DelegateTo(#{target})"
    end

    class_eval(&block) unless block.nil?
  end
end

example_usage.rb

Current = DelegateTo(:current)
now = Current[Time]

test.rb

First = DelegateTo(:first)
first = First.new [1,2,3]
# => First[[1, 2, 3]]
first == first
# => true
first == First.new([3,2,1])
# => false
first == 1 # => true
first != 1 # => false
first == 2 # => false
first != 2 # => true