module Redis::Commands::Transactions

def discard
  send_command([:discard])
end

def exec
  send_command([:exec])
end

def multi
  synchronize do |client|
    client.multi do |raw_transaction|
      yield MultiConnection.new(raw_transaction)
    end
  end
end

def unwatch
  send_command([:unwatch])
end

def watch(*keys)
  synchronize do |client|
    res = client.call_v([:watch] + keys)
    if block_given?
      begin
        yield(self)
      rescue ConnectionError
        raise
      rescue StandardError
        unwatch
        raise
      end
    else
      res
    end
  end
end