switch rval := result.(type) {
	case string:
		return FromString(rval), nil
	case float64:
		return FromFloat(rval), nil
	case int64:
		return FromInt(rval), nil
	case uint64:
		if rval <= math.MaxInt64 {
			return FromInt(int64(rval)), nil
		}
		return FromFloat(float64(rval)), nil
	case bool:
		return FromBool(rval), nil
	case jstream.KVS:
		bs, err := json.Marshal(result)

var valueBuilders = []func() *Value{
	FromNull,
	func() *Value {
		return FromBool(true)
	},
	func() *Value {
		return FromBytes([]byte("byte contents"))
	},
	func() *Value {
		return FromFloat(math.Pi)
	},
	func() *Value {
		return FromInt(0x1337)
	},
	func() *Value {
		t, err := time.Parse(time.RFC3339, "2006-01-02T15:04:05Z")
		if err != nil {
			panic(err)
		}
		return FromTimestamp(t)

	runningMax, runningMin *Value

	// Stores if at least one record has been seen
	seen bool
}

func newAggVal(fn FuncName) *aggVal {
	switch fn {
	case aggFnAvg, aggFnSum:
		return &aggVal{runningSum: FromFloat(0)}
	case aggFnMin:
		return &aggVal{runningMin: FromInt(0)}
	case aggFnMax:
		return &aggVal{runningMax: FromInt(0)}
	default:
		return &aggVal{}
	}
}