Gem::StreamUI#ask_yes_no

# File tmp/rubies/ruby-4.0.0/lib/rubygems/user_interaction.rb, line 246
def ask_yes_no(question, default = nil)
  unless tty?
    if default.nil?
      raise Gem::OperationNotSupportedError,
            "Not connected to a tty and no default specified"
    else
      return default
    end
  end

  default_answer = case default
                   when nil
                     "yn"
                   when true
                     "Yn"
                   else
                     "yN"
  end

  result = nil

  while result.nil? do
    result = case ask "#{question} [#{default_answer}]"
             when /^y/i then true
             when /^n/i then false
             when /^$/  then default
    end
  end

  result
end