Source: command.go in package github.com/go-redis/redis/v8

package redis

import (
	"context"
	"fmt"
	"net"
	"strconv"
	"time"

	"github.com/go-redis/redis/v8/internal"
	"github.com/go-redis/redis/v8/internal/proto"
	"github.com/go-redis/redis/v8/internal/util"
)

type Cmder interface {
	Name() string
	FullName() string
	Args() []interface{}
	String() string
	stringArg(int) string

	readTimeout() *time.Duration
	readReply(rd *proto.Reader) error

	SetErr(error)
	Err() error
}

func setCmdsErr(cmds []Cmder, e error) {
	for _, cmd := range cmds {
		if cmd.Err() == nil {
			cmd.SetErr(e)
		}
	}
}

func cmdsFirstErr(cmds []Cmder) error {
	for _, cmd := range cmds {
		if err := cmd.Err(); err != nil {
			return err
		}
	}
	return nil
}

func writeCmds(wr *proto.Writer, cmds []Cmder) error {
	for _, cmd := range cmds {
		if err := writeCmd(wr, cmd); err != nil {
			return err
		}
	}
	return nil
}

func writeCmd(wr *proto.Writer, cmd Cmder) error {
	return wr.WriteArgs(cmd.Args())
}

func cmdFirstKeyPos(cmd Cmder, info *CommandInfo) int {
	switch cmd.Name() {
	case "eval", "evalsha":
		if cmd.stringArg(2) != "0" {
			return 3
		}

		return 0
	case "publish":
		return 1

https://github.com/redis/redis/issues/7493

		if cmd.stringArg(1) == "usage" {
			return 2
		}
	}

	if info == nil {
		return 0
	}
	return int(info.FirstKeyPos)
}

func cmdString(cmd Cmder, val interface{}) string {
	b := make([]byte, 0, 64)

	for i, arg := range cmd.Args() {
		if i > 0 {
			b = append(b, ' ')
		}
		b = internal.AppendArg(b, arg)
	}

	if err := cmd.Err(); err != nil {
		b = append(b, ": "...)
		b = append(b, err.Error()...)
	} else if val != nil {
		b = append(b, ": "...)
		b = internal.AppendArg(b, val)
	}

	return internal.String(b)
}

------------------------------------------------------------------------------


type baseCmd struct {
	ctx  context.Context
	args []interface{}
	err  error

	_readTimeout *time.Duration
}

var _ Cmder = (*Cmd)(nil)

func (cmd *baseCmd) Name() string {
	if len(cmd.args) == 0 {
		return ""

Cmd name must be lower cased.

	return internal.ToLower(cmd.stringArg(0))
}

func (cmd *baseCmd) FullName() string {
	switch name := cmd.Name(); name {
	case "cluster", "command":
		if len(cmd.args) == 1 {
			return name
		}
		if s2, ok := cmd.args[1].(string); ok {
			return name + " " + s2
		}
		return name
	default:
		return name
	}
}

func (cmd *baseCmd) Args() []interface{} {
	return cmd.args
}

func (cmd *baseCmd) stringArg(pos int) string {
	if pos < 0 || pos >= len(cmd.args) {
		return ""
	}
	s, _ := cmd.args[pos].(string)
	return s
}

func (cmd *baseCmd) SetErr(e error) {
	cmd.err = e
}

func (cmd *baseCmd) Err() error {
	return cmd.err
}

func (cmd *baseCmd) readTimeout() *time.Duration {
	return cmd._readTimeout
}

func (cmd *baseCmd) setReadTimeout(d time.Duration) {
	cmd._readTimeout = &d
}

------------------------------------------------------------------------------


type Cmd struct {
	baseCmd

	val interface{}
}

func NewCmd(ctx context.Context, args ...interface{}) *Cmd {
	return &Cmd{
		baseCmd: baseCmd{
			ctx:  ctx,
			args: args,
		},
	}
}

func (cmd *Cmd) String() string {
	return cmdString(cmd, cmd.val)
}

func (cmd *Cmd) Val() interface{} {
	return cmd.val
}

func (cmd *Cmd) Result() (interface{}, error) {
	return cmd.val, cmd.err
}

func (cmd *Cmd) Text() (string, error) {
	if cmd.err != nil {
		return "", cmd.err
	}
	switch val := cmd.val.(type) {
	case string:
		return val, nil
	default:
		err := fmt.Errorf("redis: unexpected type=%T for String", val)
		return "", err
	}
}

func (cmd *Cmd) Int() (int, error) {
	if cmd.err != nil {
		return 0, cmd.err
	}
	switch val := cmd.val.(type) {
	case int64:
		return int(val), nil
	case string:
		return strconv.Atoi(val)
	default:
		err := fmt.Errorf("redis: unexpected type=%T for Int", val)
		return 0, err
	}
}

func (cmd *Cmd) Int64() (int64, error) {
	if cmd.err != nil {
		return 0, cmd.err
	}
	switch val := cmd.val.(type) {
	case int64:
		return val, nil
	case string:
		return strconv.ParseInt(val, 10, 64)
	default:
		err := fmt.Errorf("redis: unexpected type=%T for Int64", val)
		return 0, err
	}
}

func (cmd *Cmd) Uint64() (uint64, error) {
	if cmd.err != nil {
		return 0, cmd.err
	}
	switch val := cmd.val.(type) {
	case int64:
		return uint64(val), nil
	case string:
		return strconv.ParseUint(val, 10, 64)
	default:
		err := fmt.Errorf("redis: unexpected type=%T for Uint64", val)
		return 0, err
	}
}

func (cmd *Cmd) Float32() (float32, error) {
	if cmd.err != nil {
		return 0, cmd.err
	}
	switch val := cmd.val.(type) {
	case int64:
		return float32(val), nil
	case string:
		f, err := strconv.ParseFloat(val, 32)
		if err != nil {
			return 0, err
		}
		return float32(f), nil
	default:
		err := fmt.Errorf("redis: unexpected type=%T for Float32", val)
		return 0, err
	}
}

func (cmd *Cmd) Float64() (float64, error) {
	if cmd.err != nil {
		return 0, cmd.err
	}
	switch val := cmd.val.(type) {
	case int64:
		return float64(val), nil
	case string:
		return strconv.ParseFloat(val, 64)
	default:
		err := fmt.Errorf("redis: unexpected type=%T for Float64", val)
		return 0, err
	}
}

func (cmd *Cmd) Bool() (bool, error) {
	if cmd.err != nil {
		return false, cmd.err
	}
	switch val := cmd.val.(type) {
	case int64:
		return val != 0, nil
	case string:
		return strconv.ParseBool(val)
	default:
		err := fmt.Errorf("redis: unexpected type=%T for Bool", val)
		return false, err
	}
}

func (cmd *Cmd) readReply(rd *proto.Reader) error {
	cmd.val, cmd.err = rd.ReadReply(sliceParser)
	return cmd.err
}

sliceParser implements proto.MultiBulkParse.

func sliceParser(rd *proto.Reader, n int64) (interface{}, error) {
	vals := make([]interface{}, n)
	for i := 0; i < len(vals); i++ {
		v, err := rd.ReadReply(sliceParser)
		if err != nil {
			if err == Nil {
				vals[i] = nil
				continue
			}
			if err, ok := err.(proto.RedisError); ok {
				vals[i] = err
				continue
			}
			return nil, err
		}
		vals[i] = v
	}
	return vals, nil
}

------------------------------------------------------------------------------


type SliceCmd struct {
	baseCmd

	val []interface{}
}

var _ Cmder = (*SliceCmd)(nil)

func NewSliceCmd(ctx context.Context, args ...interface{}) *SliceCmd {
	return &SliceCmd{
		baseCmd: baseCmd{
			ctx:  ctx,
			args: args,
		},
	}
}

func (cmd *SliceCmd) Val() []interface{} {
	return cmd.val
}

func (cmd *SliceCmd) Result() ([]interface{}, error) {
	return cmd.val, cmd.err
}

func (cmd *SliceCmd) String() string {
	return cmdString(cmd, cmd.val)
}

func (cmd *SliceCmd) readReply(rd *proto.Reader) error {
	var v interface{}
	v, cmd.err = rd.ReadArrayReply(sliceParser)
	if cmd.err != nil {
		return cmd.err
	}
	cmd.val = v.([]interface{})
	return nil
}

------------------------------------------------------------------------------


type StatusCmd struct {
	baseCmd

	val string
}

var _ Cmder = (*StatusCmd)(nil)

func NewStatusCmd(ctx context.Context, args ...interface{}) *StatusCmd {
	return &StatusCmd{
		baseCmd: baseCmd{
			ctx:  ctx,
			args: args,
		},
	}
}

func (cmd *StatusCmd) Val() string {
	return cmd.val
}

func (cmd *StatusCmd) Result() (string, error) {
	return cmd.val, cmd.err
}

func (cmd *StatusCmd) String() string {
	return cmdString(cmd, cmd.val)
}

func (cmd *StatusCmd) readReply(rd *proto.Reader) error {
	cmd.val, cmd.err = rd.ReadString()
	return cmd.err
}

------------------------------------------------------------------------------


type IntCmd struct {
	baseCmd

	val int64
}

var _ Cmder = (*IntCmd)(nil)

func NewIntCmd(ctx context.Context, args ...interface{}) *IntCmd {
	return &IntCmd{
		baseCmd: baseCmd{
			ctx:  ctx,
			args: args,
		},
	}
}

func (cmd *IntCmd) Val() int64 {
	return cmd.val
}

func (cmd *IntCmd) Result() (int64, error) {
	return cmd.val, cmd.err
}

func (cmd *IntCmd) Uint64() (uint64, error) {
	return uint64(cmd.val), cmd.err
}

func (cmd *IntCmd) String() string {
	return cmdString(cmd, cmd.val)
}

func (cmd *IntCmd) readReply(rd *proto.Reader) error {
	cmd.val, cmd.err = rd.ReadIntReply()
	return cmd.err
}

------------------------------------------------------------------------------


type IntSliceCmd struct {
	baseCmd

	val []int64
}

var _ Cmder = (*IntSliceCmd)(nil)

func NewIntSliceCmd(ctx context.Context, args ...interface{}) *IntSliceCmd {
	return &IntSliceCmd{
		baseCmd: baseCmd{
			ctx:  ctx,
			args: args,
		},
	}
}

func (cmd *IntSliceCmd) Val() []int64 {
	return cmd.val
}

func (cmd *IntSliceCmd) Result() ([]int64, error) {
	return cmd.val, cmd.err
}

func (cmd *IntSliceCmd) String() string {
	return cmdString(cmd, cmd.val)
}

func (cmd *IntSliceCmd) readReply(rd *proto.Reader) error {
	_, cmd.err = rd.ReadArrayReply(func(rd *proto.Reader, n int64) (interface{}, error) {
		cmd.val = make([]int64, n)
		for i := 0; i < len(cmd.val); i++ {
			num, err := rd.ReadIntReply()
			if err != nil {
				return nil, err
			}
			cmd.val[i] = num
		}
		return nil, nil
	})
	return cmd.err
}

------------------------------------------------------------------------------


type DurationCmd struct {
	baseCmd

	val       time.Duration
	precision time.Duration
}

var _ Cmder = (*DurationCmd)(nil)

func NewDurationCmd(ctx context.Context, precision time.Duration, args ...interface{}) *DurationCmd {
	return &DurationCmd{
		baseCmd: baseCmd{
			ctx:  ctx,
			args: args,
		},
		precision: precision,
	}
}

func (cmd *DurationCmd) Val() time.Duration {
	return cmd.val
}

func (cmd *DurationCmd) Result() (time.Duration, error) {
	return cmd.val, cmd.err
}

func (cmd *DurationCmd) String() string {
	return cmdString(cmd, cmd.val)
}

func (cmd *DurationCmd) readReply(rd *proto.Reader) error {
	var n int64
	n, cmd.err = rd.ReadIntReply()
	if cmd.err != nil {
		return cmd.err
	}

-2 if the key does not exist -1 if the key exists but has no associated expire

	case -2, -1:
		cmd.val = time.Duration(n)
	default:
		cmd.val = time.Duration(n) * cmd.precision
	}
	return nil
}

------------------------------------------------------------------------------


type TimeCmd struct {
	baseCmd

	val time.Time
}

var _ Cmder = (*TimeCmd)(nil)

func NewTimeCmd(ctx context.Context, args ...interface{}) *TimeCmd {
	return &TimeCmd{
		baseCmd: baseCmd{
			ctx:  ctx,
			args: args,
		},
	}
}

func (cmd *TimeCmd) Val() time.Time {
	return cmd.val
}

func (cmd *TimeCmd) Result() (time.Time, error) {
	return cmd.val, cmd.err
}

func (cmd *TimeCmd) String() string {
	return cmdString(cmd, cmd.val)
}

func (cmd *TimeCmd) readReply(rd *proto.Reader) error {
	_, cmd.err = rd.ReadArrayReply(func(rd *proto.Reader, n int64) (interface{}, error) {
		if n != 2 {
			return nil, fmt.Errorf("got %d elements, expected 2", n)
		}

		sec, err := rd.ReadInt()
		if err != nil {
			return nil, err
		}

		microsec, err := rd.ReadInt()
		if err != nil {
			return nil, err
		}

		cmd.val = time.Unix(sec, microsec*1000)
		return nil, nil
	})
	return cmd.err
}

------------------------------------------------------------------------------


type BoolCmd struct {
	baseCmd

	val bool
}

var _ Cmder = (*BoolCmd)(nil)

func NewBoolCmd(ctx context.Context, args ...interface{}) *BoolCmd {
	return &BoolCmd{
		baseCmd: baseCmd{
			ctx:  ctx,
			args: args,
		},
	}
}

func (cmd *BoolCmd) Val() bool {
	return cmd.val
}

func (cmd *BoolCmd) Result() (bool, error) {
	return cmd.val, cmd.err
}

func (cmd *BoolCmd) String() string {
	return cmdString(cmd, cmd.val)
}

func (cmd *BoolCmd) readReply(rd *proto.Reader) error {
	var v interface{}

`SET key value NX` returns nil when key already exists. But `SETNX key value` returns bool (0/1). So convert nil to bool.

	if cmd.err == Nil {
		cmd.val = false
		cmd.err = nil
		return nil
	}
	if cmd.err != nil {
		return cmd.err
	}
	switch v := v.(type) {
	case int64:
		cmd.val = v == 1
		return nil
	case string:
		cmd.val = v == "OK"
		return nil
	default:
		cmd.err = fmt.Errorf("got %T, wanted int64 or string", v)
		return cmd.err
	}
}

------------------------------------------------------------------------------


type StringCmd struct {
	baseCmd

	val string
}

var _ Cmder = (*StringCmd)(nil)

func NewStringCmd(ctx context.Context, args ...interface{}) *StringCmd {
	return &StringCmd{
		baseCmd: baseCmd{
			ctx:  ctx,
			args: args,
		},
	}
}

func (cmd *StringCmd) Val() string {
	return cmd.val
}

func (cmd *StringCmd) Result() (string, error) {
	return cmd.Val(), cmd.err
}

func (cmd *StringCmd) Bytes() ([]byte, error) {
	return util.StringToBytes(cmd.val), cmd.err
}

func (cmd *StringCmd) Int() (int, error) {
	if cmd.err != nil {
		return 0, cmd.err
	}
	return strconv.Atoi(cmd.Val())
}

func (cmd *StringCmd) Int64() (int64, error) {
	if cmd.err != nil {
		return 0, cmd.err
	}
	return strconv.ParseInt(cmd.Val(), 10, 64)
}

func (cmd *StringCmd) Uint64() (uint64, error) {
	if cmd.err != nil {
		return 0, cmd.err
	}
	return strconv.ParseUint(cmd.Val(), 10, 64)
}

func (cmd *StringCmd) Float32() (float32, error) {
	if cmd.err != nil {
		return 0, cmd.err
	}
	f, err := strconv.ParseFloat(cmd.Val(), 32)
	if err != nil {
		return 0, err
	}
	return float32(f), nil
}

func (cmd *StringCmd) Float64() (float64, error) {
	if cmd.err != nil {
		return 0, cmd.err
	}
	return strconv.ParseFloat(cmd.Val(), 64)
}

func (cmd *StringCmd) Time() (time.Time, error) {
	if cmd.err != nil {
		return time.Time{}, cmd.err
	}
	return time.Parse(time.RFC3339Nano, cmd.Val())
}

func (cmd *StringCmd) Scan(val interface{}) error {
	if cmd.err != nil {
		return cmd.err
	}
	return proto.Scan([]byte(cmd.val), val)
}

func (cmd *StringCmd) String() string {
	return cmdString(cmd, cmd.val)
}

func (cmd *StringCmd) readReply(rd *proto.Reader) error {
	cmd.val, cmd.err = rd.ReadString()
	return cmd.err
}

------------------------------------------------------------------------------


type FloatCmd struct {
	baseCmd

	val float64
}

var _ Cmder = (*FloatCmd)(nil)

func NewFloatCmd(ctx context.Context, args ...interface{}) *FloatCmd {
	return &FloatCmd{
		baseCmd: baseCmd{
			ctx:  ctx,
			args: args,
		},
	}
}

func (cmd *FloatCmd) Val() float64 {
	return cmd.val
}

func (cmd *FloatCmd) Result() (float64, error) {
	return cmd.Val(), cmd.Err()
}

func (cmd *FloatCmd) String() string {
	return cmdString(cmd, cmd.val)
}

func (cmd *FloatCmd) readReply(rd *proto.Reader) error {
	cmd.val, cmd.err = rd.ReadFloatReply()
	return cmd.err
}

------------------------------------------------------------------------------


type StringSliceCmd struct {
	baseCmd

	val []string
}

var _ Cmder = (*StringSliceCmd)(nil)

func NewStringSliceCmd(ctx context.Context, args ...interface{}) *StringSliceCmd {
	return &StringSliceCmd{
		baseCmd: baseCmd{
			ctx:  ctx,
			args: args,
		},
	}
}

func (cmd *StringSliceCmd) Val() []string {
	return cmd.val
}

func (cmd *StringSliceCmd) Result() ([]string, error) {
	return cmd.Val(), cmd.Err()
}

func (cmd *StringSliceCmd) String() string {
	return cmdString(cmd, cmd.val)
}

func (cmd *StringSliceCmd) ScanSlice(container interface{}) error {
	return proto.ScanSlice(cmd.Val(), container)
}

func (cmd *StringSliceCmd) readReply(rd *proto.Reader) error {
	_, cmd.err = rd.ReadArrayReply(func(rd *proto.Reader, n int64) (interface{}, error) {
		cmd.val = make([]string, n)
		for i := 0; i < len(cmd.val); i++ {
			switch s, err := rd.ReadString(); {
			case err == Nil:
				cmd.val[i] = ""
			case err != nil:
				return nil, err
			default:
				cmd.val[i] = s
			}
		}
		return nil, nil
	})
	return cmd.err
}

------------------------------------------------------------------------------


type BoolSliceCmd struct {
	baseCmd

	val []bool
}

var _ Cmder = (*BoolSliceCmd)(nil)

func NewBoolSliceCmd(ctx context.Context, args ...interface{}) *BoolSliceCmd {
	return &BoolSliceCmd{
		baseCmd: baseCmd{
			ctx:  ctx,
			args: args,
		},
	}
}

func (cmd *BoolSliceCmd) Val() []bool {
	return cmd.val
}

func (cmd *BoolSliceCmd) Result() ([]bool, error) {
	return cmd.val, cmd.err
}

func (cmd *BoolSliceCmd) String() string {
	return cmdString(cmd, cmd.val)
}

func (cmd *BoolSliceCmd) readReply(rd *proto.Reader) error {
	_, cmd.err = rd.ReadArrayReply(func(rd *proto.Reader, n int64) (interface{}, error) {
		cmd.val = make([]bool, n)
		for i := 0; i < len(cmd.val); i++ {
			n, err := rd.ReadIntReply()
			if err != nil {
				return nil, err
			}
			cmd.val[i] = n == 1
		}
		return nil, nil
	})
	return cmd.err
}

------------------------------------------------------------------------------


type StringStringMapCmd struct {
	baseCmd

	val map[string]string
}

var _ Cmder = (*StringStringMapCmd)(nil)

func NewStringStringMapCmd(ctx context.Context, args ...interface{}) *StringStringMapCmd {
	return &StringStringMapCmd{
		baseCmd: baseCmd{
			ctx:  ctx,
			args: args,
		},
	}
}

func (cmd *StringStringMapCmd) Val() map[string]string {
	return cmd.val
}

func (cmd *StringStringMapCmd) Result() (map[string]string, error) {
	return cmd.val, cmd.err
}

func (cmd *StringStringMapCmd) String() string {
	return cmdString(cmd, cmd.val)
}

func (cmd *StringStringMapCmd) readReply(rd *proto.Reader) error {
	_, cmd.err = rd.ReadArrayReply(func(rd *proto.Reader, n int64) (interface{}, error) {
		cmd.val = make(map[string]string, n/2)
		for i := int64(0); i < n; i += 2 {
			key, err := rd.ReadString()
			if err != nil {
				return nil, err
			}

			value, err := rd.ReadString()
			if err != nil {
				return nil, err
			}

			cmd.val[key] = value
		}
		return nil, nil
	})
	return cmd.err
}

------------------------------------------------------------------------------


type StringIntMapCmd struct {
	baseCmd

	val map[string]int64
}

var _ Cmder = (*StringIntMapCmd)(nil)

func NewStringIntMapCmd(ctx context.Context, args ...interface{}) *StringIntMapCmd {
	return &StringIntMapCmd{
		baseCmd: baseCmd{
			ctx:  ctx,
			args: args,
		},
	}
}

func (cmd *StringIntMapCmd) Val() map[string]int64 {
	return cmd.val
}

func (cmd *StringIntMapCmd) Result() (map[string]int64, error) {
	return cmd.val, cmd.err
}

func (cmd *StringIntMapCmd) String() string {
	return cmdString(cmd, cmd.val)
}

func (cmd *StringIntMapCmd) readReply(rd *proto.Reader) error {
	_, cmd.err = rd.ReadArrayReply(func(rd *proto.Reader, n int64) (interface{}, error) {
		cmd.val = make(map[string]int64, n/2)
		for i := int64(0); i < n; i += 2 {
			key, err := rd.ReadString()
			if err != nil {
				return nil, err
			}

			n, err := rd.ReadIntReply()
			if err != nil {
				return nil, err
			}

			cmd.val[key] = n
		}
		return nil, nil
	})
	return cmd.err
}

------------------------------------------------------------------------------


type StringStructMapCmd struct {
	baseCmd

	val map[string]struct{}
}

var _ Cmder = (*StringStructMapCmd)(nil)

func NewStringStructMapCmd(ctx context.Context, args ...interface{}) *StringStructMapCmd {
	return &StringStructMapCmd{
		baseCmd: baseCmd{
			ctx:  ctx,
			args: args,
		},
	}
}

func (cmd *StringStructMapCmd) Val() map[string]struct{} {
	return cmd.val
}

func (cmd *StringStructMapCmd) Result() (map[string]struct{}, error) {
	return cmd.val, cmd.err
}

func (cmd *StringStructMapCmd) String() string {
	return cmdString(cmd, cmd.val)
}

func (cmd *StringStructMapCmd) readReply(rd *proto.Reader) error {
	_, cmd.err = rd.ReadArrayReply(func(rd *proto.Reader, n int64) (interface{}, error) {
		cmd.val = make(map[string]struct{}, n)
		for i := int64(0); i < n; i++ {
			key, err := rd.ReadString()
			if err != nil {
				return nil, err
			}
			cmd.val[key] = struct{}{}
		}
		return nil, nil
	})
	return cmd.err
}

------------------------------------------------------------------------------


type XMessage struct {
	ID     string
	Values map[string]interface{}
}

type XMessageSliceCmd struct {
	baseCmd

	val []XMessage
}

var _ Cmder = (*XMessageSliceCmd)(nil)

func NewXMessageSliceCmd(ctx context.Context, args ...interface{}) *XMessageSliceCmd {
	return &XMessageSliceCmd{
		baseCmd: baseCmd{
			ctx:  ctx,
			args: args,
		},
	}
}

func (cmd *XMessageSliceCmd) Val() []XMessage {
	return cmd.val
}

func (cmd *XMessageSliceCmd) Result() ([]XMessage, error) {
	return cmd.val, cmd.err
}

func (cmd *XMessageSliceCmd) String() string {
	return cmdString(cmd, cmd.val)
}

func (cmd *XMessageSliceCmd) readReply(rd *proto.Reader) error {
	var v interface{}
	v, cmd.err = rd.ReadArrayReply(xMessageSliceParser)
	if cmd.err != nil {
		return cmd.err
	}
	cmd.val = v.([]XMessage)
	return nil
}

xMessageSliceParser implements proto.MultiBulkParse.

func xMessageSliceParser(rd *proto.Reader, n int64) (interface{}, error) {
	msgs := make([]XMessage, n)
	for i := 0; i < len(msgs); i++ {
		i := i
		_, err := rd.ReadArrayReply(func(rd *proto.Reader, n int64) (interface{}, error) {
			id, err := rd.ReadString()
			if err != nil {
				return nil, err
			}

			var values map[string]interface{}

			v, err := rd.ReadArrayReply(stringInterfaceMapParser)
			if err != nil {
				if err != proto.Nil {
					return nil, err
				}
			} else {
				values = v.(map[string]interface{})
			}

			msgs[i] = XMessage{
				ID:     id,
				Values: values,
			}
			return nil, nil
		})
		if err != nil {
			return nil, err
		}
	}
	return msgs, nil
}

stringInterfaceMapParser implements proto.MultiBulkParse.

func stringInterfaceMapParser(rd *proto.Reader, n int64) (interface{}, error) {
	m := make(map[string]interface{}, n/2)
	for i := int64(0); i < n; i += 2 {
		key, err := rd.ReadString()
		if err != nil {
			return nil, err
		}

		value, err := rd.ReadString()
		if err != nil {
			return nil, err
		}

		m[key] = value
	}
	return m, nil
}

------------------------------------------------------------------------------


type XStream struct {
	Stream   string
	Messages []XMessage
}

type XStreamSliceCmd struct {
	baseCmd

	val []XStream
}

var _ Cmder = (*XStreamSliceCmd)(nil)

func NewXStreamSliceCmd(ctx context.Context, args ...interface{}) *XStreamSliceCmd {
	return &XStreamSliceCmd{
		baseCmd: baseCmd{
			ctx:  ctx,
			args: args,
		},
	}
}

func (cmd *XStreamSliceCmd) Val() []XStream {
	return cmd.val
}

func (cmd *XStreamSliceCmd) Result() ([]XStream, error) {
	return cmd.val, cmd.err
}

func (cmd *XStreamSliceCmd) String() string {
	return cmdString(cmd, cmd.val)
}

func (cmd *XStreamSliceCmd) readReply(rd *proto.Reader) error {
	_, cmd.err = rd.ReadArrayReply(func(rd *proto.Reader, n int64) (interface{}, error) {
		cmd.val = make([]XStream, n)
		for i := 0; i < len(cmd.val); i++ {
			i := i
			_, err := rd.ReadArrayReply(func(rd *proto.Reader, n int64) (interface{}, error) {
				if n != 2 {
					return nil, fmt.Errorf("got %d, wanted 2", n)
				}

				stream, err := rd.ReadString()
				if err != nil {
					return nil, err
				}

				v, err := rd.ReadArrayReply(xMessageSliceParser)
				if err != nil {
					return nil, err
				}

				cmd.val[i] = XStream{
					Stream:   stream,
					Messages: v.([]XMessage),
				}
				return nil, nil
			})
			if err != nil {
				return nil, err
			}
		}
		return nil, nil
	})
	return cmd.err
}

------------------------------------------------------------------------------


type XPending struct {
	Count     int64
	Lower     string
	Higher    string
	Consumers map[string]int64
}

type XPendingCmd struct {
	baseCmd
	val *XPending
}

var _ Cmder = (*XPendingCmd)(nil)

func NewXPendingCmd(ctx context.Context, args ...interface{}) *XPendingCmd {
	return &XPendingCmd{
		baseCmd: baseCmd{
			ctx:  ctx,
			args: args,
		},
	}
}

func (cmd *XPendingCmd) Val() *XPending {
	return cmd.val
}

func (cmd *XPendingCmd) Result() (*XPending, error) {
	return cmd.val, cmd.err
}

func (cmd *XPendingCmd) String() string {
	return cmdString(cmd, cmd.val)
}

func (cmd *XPendingCmd) readReply(rd *proto.Reader) error {
	_, cmd.err = rd.ReadArrayReply(func(rd *proto.Reader, n int64) (interface{}, error) {
		if n != 4 {
			return nil, fmt.Errorf("got %d, wanted 4", n)
		}

		count, err := rd.ReadIntReply()
		if err != nil {
			return nil, err
		}

		lower, err := rd.ReadString()
		if err != nil && err != Nil {
			return nil, err
		}

		higher, err := rd.ReadString()
		if err != nil && err != Nil {
			return nil, err
		}

		cmd.val = &XPending{
			Count:  count,
			Lower:  lower,
			Higher: higher,
		}
		_, err = rd.ReadArrayReply(func(rd *proto.Reader, n int64) (interface{}, error) {
			for i := int64(0); i < n; i++ {
				_, err = rd.ReadArrayReply(func(rd *proto.Reader, n int64) (interface{}, error) {
					if n != 2 {
						return nil, fmt.Errorf("got %d, wanted 2", n)
					}

					consumerName, err := rd.ReadString()
					if err != nil {
						return nil, err
					}

					consumerPending, err := rd.ReadInt()
					if err != nil {
						return nil, err
					}

					if cmd.val.Consumers == nil {
						cmd.val.Consumers = make(map[string]int64)
					}
					cmd.val.Consumers[consumerName] = consumerPending

					return nil, nil
				})
				if err != nil {
					return nil, err
				}
			}
			return nil, nil
		})
		if err != nil && err != Nil {
			return nil, err
		}

		return nil, nil
	})
	return cmd.err
}

------------------------------------------------------------------------------


type XPendingExt struct {
	ID         string
	Consumer   string
	Idle       time.Duration
	RetryCount int64
}

type XPendingExtCmd struct {
	baseCmd
	val []XPendingExt
}

var _ Cmder = (*XPendingExtCmd)(nil)

func NewXPendingExtCmd(ctx context.Context, args ...interface{}) *XPendingExtCmd {
	return &XPendingExtCmd{
		baseCmd: baseCmd{
			ctx:  ctx,
			args: args,
		},
	}
}

func (cmd *XPendingExtCmd) Val() []XPendingExt {
	return cmd.val
}

func (cmd *XPendingExtCmd) Result() ([]XPendingExt, error) {
	return cmd.val, cmd.err
}

func (cmd *XPendingExtCmd) String() string {
	return cmdString(cmd, cmd.val)
}

func (cmd *XPendingExtCmd) readReply(rd *proto.Reader) error {
	_, cmd.err = rd.ReadArrayReply(func(rd *proto.Reader, n int64) (interface{}, error) {
		cmd.val = make([]XPendingExt, 0, n)
		for i := int64(0); i < n; i++ {
			_, err := rd.ReadArrayReply(func(rd *proto.Reader, n int64) (interface{}, error) {
				if n != 4 {
					return nil, fmt.Errorf("got %d, wanted 4", n)
				}

				id, err := rd.ReadString()
				if err != nil {
					return nil, err
				}

				consumer, err := rd.ReadString()
				if err != nil && err != Nil {
					return nil, err
				}

				idle, err := rd.ReadIntReply()
				if err != nil && err != Nil {
					return nil, err
				}

				retryCount, err := rd.ReadIntReply()
				if err != nil && err != Nil {
					return nil, err
				}

				cmd.val = append(cmd.val, XPendingExt{
					ID:         id,
					Consumer:   consumer,
					Idle:       time.Duration(idle) * time.Millisecond,
					RetryCount: retryCount,
				})
				return nil, nil
			})
			if err != nil {
				return nil, err
			}
		}
		return nil, nil
	})
	return cmd.err
}

------------------------------------------------------------------------------


type XInfoGroupsCmd struct {
	baseCmd
	val []XInfoGroups
}

type XInfoGroups struct {
	Name            string
	Consumers       int64
	Pending         int64
	LastDeliveredID string
}

var _ Cmder = (*XInfoGroupsCmd)(nil)

func NewXInfoGroupsCmd(ctx context.Context, stream string) *XInfoGroupsCmd {
	return &XInfoGroupsCmd{
		baseCmd: baseCmd{
			ctx:  ctx,
			args: []interface{}{"xinfo", "groups", stream},
		},
	}
}

func (cmd *XInfoGroupsCmd) Val() []XInfoGroups {
	return cmd.val
}

func (cmd *XInfoGroupsCmd) Result() ([]XInfoGroups, error) {
	return cmd.val, cmd.err
}

func (cmd *XInfoGroupsCmd) String() string {
	return cmdString(cmd, cmd.val)
}

func (cmd *XInfoGroupsCmd) readReply(rd *proto.Reader) error {
	_, cmd.err = rd.ReadArrayReply(
		func(rd *proto.Reader, n int64) (interface{}, error) {
			for i := int64(0); i < n; i++ {
				v, err := rd.ReadReply(xGroupInfoParser)
				if err != nil {
					return nil, err
				}
				cmd.val = append(cmd.val, v.(XInfoGroups))
			}
			return nil, nil
		})
	return nil
}

func xGroupInfoParser(rd *proto.Reader, n int64) (interface{}, error) {
	if n != 8 {
		return nil, fmt.Errorf("redis: got %d elements in XINFO GROUPS reply,"+
			"wanted 8", n)
	}
	var (
		err error
		grp XInfoGroups
		key string
		val string
	)

	for i := 0; i < 4; i++ {
		key, err = rd.ReadString()
		if err != nil {
			return nil, err
		}
		val, err = rd.ReadString()
		if err != nil {
			return nil, err
		}
		switch key {
		case "name":
			grp.Name = val
		case "consumers":
			grp.Consumers, err = strconv.ParseInt(val, 0, 64)
		case "pending":
			grp.Pending, err = strconv.ParseInt(val, 0, 64)
		case "last-delivered-id":
			grp.LastDeliveredID = val
		default:
			return nil, fmt.Errorf("redis: unexpected content %s "+
				"in XINFO GROUPS reply", key)
		}
		if err != nil {
			return nil, err
		}
	}
	return grp, err
}

------------------------------------------------------------------------------


type ZSliceCmd struct {
	baseCmd

	val []Z
}

var _ Cmder = (*ZSliceCmd)(nil)

func NewZSliceCmd(ctx context.Context, args ...interface{}) *ZSliceCmd {
	return &ZSliceCmd{
		baseCmd: baseCmd{
			ctx:  ctx,
			args: args,
		},
	}
}

func (cmd *ZSliceCmd) Val() []Z {
	return cmd.val
}

func (cmd *ZSliceCmd) Result() ([]Z, error) {
	return cmd.val, cmd.err
}

func (cmd *ZSliceCmd) String() string {
	return cmdString(cmd, cmd.val)
}

func (cmd *ZSliceCmd) readReply(rd *proto.Reader) error {
	_, cmd.err = rd.ReadArrayReply(func(rd *proto.Reader, n int64) (interface{}, error) {
		cmd.val = make([]Z, n/2)
		for i := 0; i < len(cmd.val); i++ {
			member, err := rd.ReadString()
			if err != nil {
				return nil, err
			}

			score, err := rd.ReadFloatReply()
			if err != nil {
				return nil, err
			}

			cmd.val[i] = Z{
				Member: member,
				Score:  score,
			}
		}
		return nil, nil
	})
	return cmd.err
}

------------------------------------------------------------------------------


type ZWithKeyCmd struct {
	baseCmd

	val *ZWithKey
}

var _ Cmder = (*ZWithKeyCmd)(nil)

func NewZWithKeyCmd(ctx context.Context, args ...interface{}) *ZWithKeyCmd {
	return &ZWithKeyCmd{
		baseCmd: baseCmd{
			ctx:  ctx,
			args: args,
		},
	}
}

func (cmd *ZWithKeyCmd) Val() *ZWithKey {
	return cmd.val
}

func (cmd *ZWithKeyCmd) Result() (*ZWithKey, error) {
	return cmd.Val(), cmd.Err()
}

func (cmd *ZWithKeyCmd) String() string {
	return cmdString(cmd, cmd.val)
}

func (cmd *ZWithKeyCmd) readReply(rd *proto.Reader) error {
	_, cmd.err = rd.ReadArrayReply(func(rd *proto.Reader, n int64) (interface{}, error) {
		if n != 3 {
			return nil, fmt.Errorf("got %d elements, expected 3", n)
		}

		cmd.val = &ZWithKey{}
		var err error

		cmd.val.Key, err = rd.ReadString()
		if err != nil {
			return nil, err
		}

		cmd.val.Member, err = rd.ReadString()
		if err != nil {
			return nil, err
		}

		cmd.val.Score, err = rd.ReadFloatReply()
		if err != nil {
			return nil, err
		}

		return nil, nil
	})
	return cmd.err
}

------------------------------------------------------------------------------


type ScanCmd struct {
	baseCmd

	page   []string
	cursor uint64

	process cmdable
}

var _ Cmder = (*ScanCmd)(nil)

func NewScanCmd(ctx context.Context, process cmdable, args ...interface{}) *ScanCmd {
	return &ScanCmd{
		baseCmd: baseCmd{
			ctx:  ctx,
			args: args,
		},
		process: process,
	}
}

func (cmd *ScanCmd) Val() (keys []string, cursor uint64) {
	return cmd.page, cmd.cursor
}

func (cmd *ScanCmd) Result() (keys []string, cursor uint64, err error) {
	return cmd.page, cmd.cursor, cmd.err
}

func (cmd *ScanCmd) String() string {
	return cmdString(cmd, cmd.page)
}

func (cmd *ScanCmd) readReply(rd *proto.Reader) error {
	cmd.page, cmd.cursor, cmd.err = rd.ReadScanReply()
	return cmd.err
}

Iterator creates a new ScanIterator.

func (cmd *ScanCmd) Iterator() *ScanIterator {
	return &ScanIterator{
		cmd: cmd,
	}
}

------------------------------------------------------------------------------


type ClusterNode struct {
	ID   string
	Addr string
}

type ClusterSlot struct {
	Start int
	End   int
	Nodes []ClusterNode
}

type ClusterSlotsCmd struct {
	baseCmd

	val []ClusterSlot
}

var _ Cmder = (*ClusterSlotsCmd)(nil)

func NewClusterSlotsCmd(ctx context.Context, args ...interface{}) *ClusterSlotsCmd {
	return &ClusterSlotsCmd{
		baseCmd: baseCmd{
			ctx:  ctx,
			args: args,
		},
	}
}

func (cmd *ClusterSlotsCmd) Val() []ClusterSlot {
	return cmd.val
}

func (cmd *ClusterSlotsCmd) Result() ([]ClusterSlot, error) {
	return cmd.Val(), cmd.Err()
}

func (cmd *ClusterSlotsCmd) String() string {
	return cmdString(cmd, cmd.val)
}

func (cmd *ClusterSlotsCmd) readReply(rd *proto.Reader) error {
	_, cmd.err = rd.ReadArrayReply(func(rd *proto.Reader, n int64) (interface{}, error) {
		cmd.val = make([]ClusterSlot, n)
		for i := 0; i < len(cmd.val); i++ {
			n, err := rd.ReadArrayLen()
			if err != nil {
				return nil, err
			}
			if n < 2 {
				err := fmt.Errorf("redis: got %d elements in cluster info, expected at least 2", n)
				return nil, err
			}

			start, err := rd.ReadIntReply()
			if err != nil {
				return nil, err
			}

			end, err := rd.ReadIntReply()
			if err != nil {
				return nil, err
			}

			nodes := make([]ClusterNode, n-2)
			for j := 0; j < len(nodes); j++ {
				n, err := rd.ReadArrayLen()
				if err != nil {
					return nil, err
				}
				if n != 2 && n != 3 {
					err := fmt.Errorf("got %d elements in cluster info address, expected 2 or 3", n)
					return nil, err
				}

				ip, err := rd.ReadString()
				if err != nil {
					return nil, err
				}

				port, err := rd.ReadString()
				if err != nil {
					return nil, err
				}

				nodes[j].Addr = net.JoinHostPort(ip, port)

				if n == 3 {
					id, err := rd.ReadString()
					if err != nil {
						return nil, err
					}
					nodes[j].ID = id
				}
			}

			cmd.val[i] = ClusterSlot{
				Start: int(start),
				End:   int(end),
				Nodes: nodes,
			}
		}
		return nil, nil
	})
	return cmd.err
}

------------------------------------------------------------------------------

GeoLocation is used with GeoAdd to add geospatial location.

type GeoLocation struct {
	Name                      string
	Longitude, Latitude, Dist float64
	GeoHash                   int64
}

GeoRadiusQuery is used with GeoRadius to query geospatial index.

type GeoRadiusQuery struct {

Can be m, km, ft, or mi. Default is km.

	Unit        string
	WithCoord   bool
	WithDist    bool
	WithGeoHash bool

Can be ASC or DESC. Default is no sort order.

	Sort      string
	Store     string
	StoreDist string
}

type GeoLocationCmd struct {
	baseCmd

	q         *GeoRadiusQuery
	locations []GeoLocation
}

var _ Cmder = (*GeoLocationCmd)(nil)

func NewGeoLocationCmd(ctx context.Context, q *GeoRadiusQuery, args ...interface{}) *GeoLocationCmd {
	return &GeoLocationCmd{
		baseCmd: baseCmd{
			ctx:  ctx,
			args: geoLocationArgs(q, args...),
		},
		q: q,
	}
}

func geoLocationArgs(q *GeoRadiusQuery, args ...interface{}) []interface{} {
	args = append(args, q.Radius)
	if q.Unit != "" {
		args = append(args, q.Unit)
	} else {
		args = append(args, "km")
	}
	if q.WithCoord {
		args = append(args, "withcoord")
	}
	if q.WithDist {
		args = append(args, "withdist")
	}
	if q.WithGeoHash {
		args = append(args, "withhash")
	}
	if q.Count > 0 {
		args = append(args, "count", q.Count)
	}
	if q.Sort != "" {
		args = append(args, q.Sort)
	}
	if q.Store != "" {
		args = append(args, "store")
		args = append(args, q.Store)
	}
	if q.StoreDist != "" {
		args = append(args, "storedist")
		args = append(args, q.StoreDist)
	}
	return args
}

func (cmd *GeoLocationCmd) Val() []GeoLocation {
	return cmd.locations
}

func (cmd *GeoLocationCmd) Result() ([]GeoLocation, error) {
	return cmd.locations, cmd.err
}

func (cmd *GeoLocationCmd) String() string {
	return cmdString(cmd, cmd.locations)
}

func (cmd *GeoLocationCmd) readReply(rd *proto.Reader) error {
	var v interface{}
	v, cmd.err = rd.ReadArrayReply(newGeoLocationSliceParser(cmd.q))
	if cmd.err != nil {
		return cmd.err
	}
	cmd.locations = v.([]GeoLocation)
	return nil
}

func newGeoLocationSliceParser(q *GeoRadiusQuery) proto.MultiBulkParse {
	return func(rd *proto.Reader, n int64) (interface{}, error) {
		locs := make([]GeoLocation, 0, n)
		for i := int64(0); i < n; i++ {
			v, err := rd.ReadReply(newGeoLocationParser(q))
			if err != nil {
				return nil, err
			}
			switch vv := v.(type) {
			case string:
				locs = append(locs, GeoLocation{
					Name: vv,
				})

TODO: avoid copying

				locs = append(locs, *vv)
			default:
				return nil, fmt.Errorf("got %T, expected string or *GeoLocation", v)
			}
		}
		return locs, nil
	}
}

func newGeoLocationParser(q *GeoRadiusQuery) proto.MultiBulkParse {
	return func(rd *proto.Reader, n int64) (interface{}, error) {
		var loc GeoLocation
		var err error

		loc.Name, err = rd.ReadString()
		if err != nil {
			return nil, err
		}
		if q.WithDist {
			loc.Dist, err = rd.ReadFloatReply()
			if err != nil {
				return nil, err
			}
		}
		if q.WithGeoHash {
			loc.GeoHash, err = rd.ReadIntReply()
			if err != nil {
				return nil, err
			}
		}
		if q.WithCoord {
			n, err := rd.ReadArrayLen()
			if err != nil {
				return nil, err
			}
			if n != 2 {
				return nil, fmt.Errorf("got %d coordinates, expected 2", n)
			}

			loc.Longitude, err = rd.ReadFloatReply()
			if err != nil {
				return nil, err
			}
			loc.Latitude, err = rd.ReadFloatReply()
			if err != nil {
				return nil, err
			}
		}

		return &loc, nil
	}
}

------------------------------------------------------------------------------


type GeoPos struct {
	Longitude, Latitude float64
}

type GeoPosCmd struct {
	baseCmd

	val []*GeoPos
}

var _ Cmder = (*GeoPosCmd)(nil)

func NewGeoPosCmd(ctx context.Context, args ...interface{}) *GeoPosCmd {
	return &GeoPosCmd{
		baseCmd: baseCmd{
			ctx:  ctx,
			args: args,
		},
	}
}

func (cmd *GeoPosCmd) Val() []*GeoPos {
	return cmd.val
}

func (cmd *GeoPosCmd) Result() ([]*GeoPos, error) {
	return cmd.Val(), cmd.Err()
}

func (cmd *GeoPosCmd) String() string {
	return cmdString(cmd, cmd.val)
}

func (cmd *GeoPosCmd) readReply(rd *proto.Reader) error {
	_, cmd.err = rd.ReadArrayReply(func(rd *proto.Reader, n int64) (interface{}, error) {
		cmd.val = make([]*GeoPos, n)
		for i := 0; i < len(cmd.val); i++ {
			i := i
			_, err := rd.ReadReply(func(rd *proto.Reader, n int64) (interface{}, error) {
				longitude, err := rd.ReadFloatReply()
				if err != nil {
					return nil, err
				}

				latitude, err := rd.ReadFloatReply()
				if err != nil {
					return nil, err
				}

				cmd.val[i] = &GeoPos{
					Longitude: longitude,
					Latitude:  latitude,
				}
				return nil, nil
			})
			if err != nil {
				if err == Nil {
					cmd.val[i] = nil
					continue
				}
				return nil, err
			}
		}
		return nil, nil
	})
	return cmd.err
}

------------------------------------------------------------------------------


type CommandInfo struct {
	Name        string
	Arity       int8
	Flags       []string
	ACLFlags    []string
	FirstKeyPos int8
	LastKeyPos  int8
	StepCount   int8
	ReadOnly    bool
}

type CommandsInfoCmd struct {
	baseCmd

	val map[string]*CommandInfo
}

var _ Cmder = (*CommandsInfoCmd)(nil)

func NewCommandsInfoCmd(ctx context.Context, args ...interface{}) *CommandsInfoCmd {
	return &CommandsInfoCmd{
		baseCmd: baseCmd{
			ctx:  ctx,
			args: args,
		},
	}
}

func (cmd *CommandsInfoCmd) Val() map[string]*CommandInfo {
	return cmd.val
}

func (cmd *CommandsInfoCmd) Result() (map[string]*CommandInfo, error) {
	return cmd.Val(), cmd.Err()
}

func (cmd *CommandsInfoCmd) String() string {
	return cmdString(cmd, cmd.val)
}

func (cmd *CommandsInfoCmd) readReply(rd *proto.Reader) error {
	_, cmd.err = rd.ReadArrayReply(func(rd *proto.Reader, n int64) (interface{}, error) {
		cmd.val = make(map[string]*CommandInfo, n)
		for i := int64(0); i < n; i++ {
			v, err := rd.ReadReply(commandInfoParser)
			if err != nil {
				return nil, err
			}
			vv := v.(*CommandInfo)
			cmd.val[vv.Name] = vv
		}
		return nil, nil
	})
	return cmd.err
}

func commandInfoParser(rd *proto.Reader, n int64) (interface{}, error) {
	const numArgRedis5 = 6
	const numArgRedis6 = 7

	switch n {

continue

	default:
		return nil, fmt.Errorf("redis: got %d elements in COMMAND reply, wanted 7", n)
	}

	var cmd CommandInfo
	var err error

	cmd.Name, err = rd.ReadString()
	if err != nil {
		return nil, err
	}

	arity, err := rd.ReadIntReply()
	if err != nil {
		return nil, err
	}
	cmd.Arity = int8(arity)

	_, err = rd.ReadReply(func(rd *proto.Reader, n int64) (interface{}, error) {
		cmd.Flags = make([]string, n)
		for i := 0; i < len(cmd.Flags); i++ {
			switch s, err := rd.ReadString(); {
			case err == Nil:
				cmd.Flags[i] = ""
			case err != nil:
				return nil, err
			default:
				cmd.Flags[i] = s
			}
		}
		return nil, nil
	})
	if err != nil {
		return nil, err
	}

	firstKeyPos, err := rd.ReadIntReply()
	if err != nil {
		return nil, err
	}
	cmd.FirstKeyPos = int8(firstKeyPos)

	lastKeyPos, err := rd.ReadIntReply()
	if err != nil {
		return nil, err
	}
	cmd.LastKeyPos = int8(lastKeyPos)

	stepCount, err := rd.ReadIntReply()
	if err != nil {
		return nil, err
	}
	cmd.StepCount = int8(stepCount)

	for _, flag := range cmd.Flags {
		if flag == "readonly" {
			cmd.ReadOnly = true
			break
		}
	}

	if n == numArgRedis5 {
		return &cmd, nil
	}

	_, err = rd.ReadReply(func(rd *proto.Reader, n int64) (interface{}, error) {
		cmd.ACLFlags = make([]string, n)
		for i := 0; i < len(cmd.ACLFlags); i++ {
			switch s, err := rd.ReadString(); {
			case err == Nil:
				cmd.ACLFlags[i] = ""
			case err != nil:
				return nil, err
			default:
				cmd.ACLFlags[i] = s
			}
		}
		return nil, nil
	})
	if err != nil {
		return nil, err
	}

	return &cmd, nil
}

------------------------------------------------------------------------------


type cmdsInfoCache struct {
	fn func() (map[string]*CommandInfo, error)

	once internal.Once
	cmds map[string]*CommandInfo
}

func newCmdsInfoCache(fn func() (map[string]*CommandInfo, error)) *cmdsInfoCache {
	return &cmdsInfoCache{
		fn: fn,
	}
}

func (c *cmdsInfoCache) Get() (map[string]*CommandInfo, error) {
	err := c.once.Do(func() error {
		cmds, err := c.fn()
		if err != nil {
			return err
		}

Extensions have cmd names in upper case. Convert them to lower case.

		for k, v := range cmds {
			lower := internal.ToLower(k)
			if lower != k {
				cmds[lower] = v
			}
		}

		c.cmds = cmds
		return nil
	})
	return c.cmds, err
}

------------------------------------------------------------------------------


type SlowLog struct {
	ID       int64
	Time     time.Time
	Duration time.Duration

These are also optional fields emitted only by Redis 4.0 or greater: https://redis.io/commands/slowlog#output-format

	ClientAddr string
	ClientName string
}

type SlowLogCmd struct {
	baseCmd

	val []SlowLog
}

var _ Cmder = (*SlowLogCmd)(nil)

func NewSlowLogCmd(ctx context.Context, args ...interface{}) *SlowLogCmd {
	return &SlowLogCmd{
		baseCmd: baseCmd{
			ctx:  ctx,
			args: args,
		},
	}
}

func (cmd *SlowLogCmd) Val() []SlowLog {
	return cmd.val
}

func (cmd *SlowLogCmd) Result() ([]SlowLog, error) {
	return cmd.Val(), cmd.Err()
}

func (cmd *SlowLogCmd) String() string {
	return cmdString(cmd, cmd.val)
}

func (cmd *SlowLogCmd) readReply(rd *proto.Reader) error {
	_, cmd.err = rd.ReadArrayReply(func(rd *proto.Reader, n int64) (interface{}, error) {
		cmd.val = make([]SlowLog, n)
		for i := 0; i < len(cmd.val); i++ {
			n, err := rd.ReadArrayLen()
			if err != nil {
				return nil, err
			}
			if n < 4 {
				err := fmt.Errorf("redis: got %d elements in slowlog get, expected at least 4", n)
				return nil, err
			}

			id, err := rd.ReadIntReply()
			if err != nil {
				return nil, err
			}

			createdAt, err := rd.ReadIntReply()
			if err != nil {
				return nil, err
			}
			createdAtTime := time.Unix(createdAt, 0)

			costs, err := rd.ReadIntReply()
			if err != nil {
				return nil, err
			}
			costsDuration := time.Duration(costs) * time.Microsecond

			cmdLen, err := rd.ReadArrayLen()
			if err != nil {
				return nil, err
			}
			if cmdLen < 1 {
				err := fmt.Errorf("redis: got %d elements commands reply in slowlog get, expected at least 1", cmdLen)
				return nil, err
			}

			cmdString := make([]string, cmdLen)
			for i := 0; i < int(cmdLen); i++ {
				cmdString[i], err = rd.ReadString()
				if err != nil {
					return nil, err
				}
			}

			var address, name string
			for i := 4; i < int(n); i++ {
				str, err := rd.ReadString()
				if err != nil {
					return nil, err
				}
				if i == 4 {
					address = str
				} else if i == 5 {
					name = str
				}
			}

			cmd.val[i] = SlowLog{
				ID:         id,
				Time:       createdAtTime,
				Duration:   costsDuration,
				Args:       cmdString,
				ClientAddr: address,
				ClientName: name,
			}
		}
		return nil, nil
	})
	return cmd.err