Gem::StreamUI#ask_yes_no

# File tmp/rubies/ruby-3.2.0/lib/rubygems/user_interaction.rb, line 250
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
    else            nil
    end
  end

  return result
end