class RSpec::Matchers::BuiltIn::OperatorMatcher

def self.use_custom_matcher_or_delegate(operator)
  define_method(operator) do |expected|
    if !has_non_generic_implementation_of?(operator) && matcher = OperatorMatcher.get(@actual.class, operator)
      @actual.__send__(::RSpec::Matchers.last_should, matcher.new(expected))
    else
      eval_match(@actual, operator, expected)
    end
  end
  negative_operator = operator.sub(/^=/, '!')
  if negative_operator != operator && respond_to?(negative_operator)
    define_method(negative_operator) do |expected|
      opposite_should = ::RSpec::Matchers.last_should == :should ? :should_not : :should
      raise "RSpec does not support `#{::RSpec::Matchers.last_should} #{negative_operator} expected`.  " +
        "Use `#{opposite_should} #{operator} expected` instead."
    end
  end
end

def description
  "#{@operator} #{@expected.inspect}"
end

def eval_match(actual, operator, expected)
  ::RSpec::Matchers.last_matcher = self
  @operator, @expected = operator, expected
  __delegate_operator(actual, operator, expected)
end

def fail_with_message(message)
  RSpec::Expectations.fail_with(message, @expected, @actual)
end

def get(klass, operator)
  klass.ancestors.each { |ancestor|
    matcher = registry[ancestor] && registry[ancestor][operator]
    return matcher if matcher
  }
  nil
end

def has_non_generic_implementation_of?(op)
  Expectations.method_handle_for(@actual, op).owner != ::Kernel
rescue NameError
  false
end

def has_non_generic_implementation_of?(op)
  # This is a bit of a hack, but:
  #
  # {}.method(:=~).to_s # => "#<Method: Hash(Kernel)#=~>"
  #
  # In the absence of Method#owner, this is the best we
  # can do to see if the method comes from Kernel.
  !Expectations.method_handle_for(@actual, op).to_s.include?('(Kernel)')
rescue NameError
  false
end

def initialize(actual)
  @actual = actual
end

def register(klass, operator, matcher)
  registry[klass] ||= {}
  registry[klass][operator] = matcher
end

def registry
  @registry ||= {}
end

def unregister(klass, operator)
  registry[klass] && registry[klass].delete(operator)
end