Playing around with a Bottom object and try operator.

bottom_try_spec.rb

require 'rspec/given'

class Object
  def _?
    self
  end
  def _
    self
  end
end

class Bottom
  def bottom?
    true
  end
  def method_missing(sym, *args, &block)
    self
  end
  def _
    nil
  end
  def self.instance
    @instance ||= Bottom.new
  end
end

class NilClass
  def _?
    Bottom.instance
  end
end

describe "_?" do
  S = Struct.new(:item)

  context "with a real object" do
    Given(:obj) { S.new(1) }
    When(:result) { obj._?.item }
    Then { result.should == 1 }
    Then { result._.should == 1 }
  end

  context "with a nil object" do
    When(:result) { nil._?.item }
    Then { result.should be_bottom }
    Then { result._.should be_nil }
  end

  context "with a chain of nils" do
    Given(:obj) { S.new(nil) }
    When(:result) { obj._?.item._?.item._?.item }
    Then { result.should be_bottom }
    Then { result._.should be_nil }
  end

  context "with a chain of objects" do
    Given(:obj) { S.new(S.new(S.new(5))) }
    When(:result) { obj._?.item._?.item._?.item }
    Then { result.should == 5 }
    Then { result._.should == 5 }
  end
end