Ydb stable 22-4-4322.4.43

x-stable-origin-commit: 8d49d46cc834835bf3e50870516acd7376a63bcf

1 files changed, 1079 insertions, 0 deletions

diff --git a/contrib/go/_std_1.18/src/flag/flag.go b/contrib/go/_std_1.18/src/flag/flag.go
new file mode 100644
index 0000000000..4e2af450c5
--- /dev/null
+++ b/contrib/go/_std_1.18/src/flag/flag.go
@@ -0,0 +1,1079 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+/*
+	Package flag implements command-line flag parsing.
+
+	Usage
+
+	Define flags using flag.String(), Bool(), Int(), etc.
+
+	This declares an integer flag, -n, stored in the pointer nFlag, with type *int:
+		import "flag"
+		var nFlag = flag.Int("n", 1234, "help message for flag n")
+	If you like, you can bind the flag to a variable using the Var() functions.
+		var flagvar int
+		func init() {
+			flag.IntVar(&flagvar, "flagname", 1234, "help message for flagname")
+		}
+	Or you can create custom flags that satisfy the Value interface (with
+	pointer receivers) and couple them to flag parsing by
+		flag.Var(&flagVal, "name", "help message for flagname")
+	For such flags, the default value is just the initial value of the variable.
+
+	After all flags are defined, call
+		flag.Parse()
+	to parse the command line into the defined flags.
+
+	Flags may then be used directly. If you're using the flags themselves,
+	they are all pointers; if you bind to variables, they're values.
+		fmt.Println("ip has value ", *ip)
+		fmt.Println("flagvar has value ", flagvar)
+
+	After parsing, the arguments following the flags are available as the
+	slice flag.Args() or individually as flag.Arg(i).
+	The arguments are indexed from 0 through flag.NArg()-1.
+
+	Command line flag syntax
+
+	The following forms are permitted:
+
+		-flag
+		-flag=x
+		-flag x  // non-boolean flags only
+	One or two minus signs may be used; they are equivalent.
+	The last form is not permitted for boolean flags because the
+	meaning of the command
+		cmd -x *
+	where * is a Unix shell wildcard, will change if there is a file
+	called 0, false, etc. You must use the -flag=false form to turn
+	off a boolean flag.
+
+	Flag parsing stops just before the first non-flag argument
+	("-" is a non-flag argument) or after the terminator "--".
+
+	Integer flags accept 1234, 0664, 0x1234 and may be negative.
+	Boolean flags may be:
+		1, 0, t, f, T, F, true, false, TRUE, FALSE, True, False
+	Duration flags accept any input valid for time.ParseDuration.
+
+	The default set of command-line flags is controlled by
+	top-level functions.  The FlagSet type allows one to define
+	independent sets of flags, such as to implement subcommands
+	in a command-line interface. The methods of FlagSet are
+	analogous to the top-level functions for the command-line
+	flag set.
+*/
+package flag
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"reflect"
+	"sort"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// ErrHelp is the error returned if the -help or -h flag is invoked
+// but no such flag is defined.
+var ErrHelp = errors.New("flag: help requested")
+
+// errParse is returned by Set if a flag's value fails to parse, such as with an invalid integer for Int.
+// It then gets wrapped through failf to provide more information.
+var errParse = errors.New("parse error")
+
+// errRange is returned by Set if a flag's value is out of range.
+// It then gets wrapped through failf to provide more information.
+var errRange = errors.New("value out of range")
+
+func numError(err error) error {
+	ne, ok := err.(*strconv.NumError)
+	if !ok {
+		return err
+	}
+	if ne.Err == strconv.ErrSyntax {
+		return errParse
+	}
+	if ne.Err == strconv.ErrRange {
+		return errRange
+	}
+	return err
+}
+
+// -- bool Value
+type boolValue bool
+
+func newBoolValue(val bool, p *bool) *boolValue {
+	*p = val
+	return (*boolValue)(p)
+}
+
+func (b *boolValue) Set(s string) error {
+	v, err := strconv.ParseBool(s)
+	if err != nil {
+		err = errParse
+	}
+	*b = boolValue(v)
+	return err
+}
+
+func (b *boolValue) Get() any { return bool(*b) }
+
+func (b *boolValue) String() string { return strconv.FormatBool(bool(*b)) }
+
+func (b *boolValue) IsBoolFlag() bool { return true }
+
+// optional interface to indicate boolean flags that can be
+// supplied without "=value" text
+type boolFlag interface {
+	Value
+	IsBoolFlag() bool
+}
+
+// -- int Value
+type intValue int
+
+func newIntValue(val int, p *int) *intValue {
+	*p = val
+	return (*intValue)(p)
+}
+
+func (i *intValue) Set(s string) error {
+	v, err := strconv.ParseInt(s, 0, strconv.IntSize)
+	if err != nil {
+		err = numError(err)
+	}
+	*i = intValue(v)
+	return err
+}
+
+func (i *intValue) Get() any { return int(*i) }
+
+func (i *intValue) String() string { return strconv.Itoa(int(*i)) }
+
+// -- int64 Value
+type int64Value int64
+
+func newInt64Value(val int64, p *int64) *int64Value {
+	*p = val
+	return (*int64Value)(p)
+}
+
+func (i *int64Value) Set(s string) error {
+	v, err := strconv.ParseInt(s, 0, 64)
+	if err != nil {
+		err = numError(err)
+	}
+	*i = int64Value(v)
+	return err
+}
+
+func (i *int64Value) Get() any { return int64(*i) }
+
+func (i *int64Value) String() string { return strconv.FormatInt(int64(*i), 10) }
+
+// -- uint Value
+type uintValue uint
+
+func newUintValue(val uint, p *uint) *uintValue {
+	*p = val
+	return (*uintValue)(p)
+}
+
+func (i *uintValue) Set(s string) error {
+	v, err := strconv.ParseUint(s, 0, strconv.IntSize)
+	if err != nil {
+		err = numError(err)
+	}
+	*i = uintValue(v)
+	return err
+}
+
+func (i *uintValue) Get() any { return uint(*i) }
+
+func (i *uintValue) String() string { return strconv.FormatUint(uint64(*i), 10) }
+
+// -- uint64 Value
+type uint64Value uint64
+
+func newUint64Value(val uint64, p *uint64) *uint64Value {
+	*p = val
+	return (*uint64Value)(p)
+}
+
+func (i *uint64Value) Set(s string) error {
+	v, err := strconv.ParseUint(s, 0, 64)
+	if err != nil {
+		err = numError(err)
+	}
+	*i = uint64Value(v)
+	return err
+}
+
+func (i *uint64Value) Get() any { return uint64(*i) }
+
+func (i *uint64Value) String() string { return strconv.FormatUint(uint64(*i), 10) }
+
+// -- string Value
+type stringValue string
+
+func newStringValue(val string, p *string) *stringValue {
+	*p = val
+	return (*stringValue)(p)
+}
+
+func (s *stringValue) Set(val string) error {
+	*s = stringValue(val)
+	return nil
+}
+
+func (s *stringValue) Get() any { return string(*s) }
+
+func (s *stringValue) String() string { return string(*s) }
+
+// -- float64 Value
+type float64Value float64
+
+func newFloat64Value(val float64, p *float64) *float64Value {
+	*p = val
+	return (*float64Value)(p)
+}
+
+func (f *float64Value) Set(s string) error {
+	v, err := strconv.ParseFloat(s, 64)
+	if err != nil {
+		err = numError(err)
+	}
+	*f = float64Value(v)
+	return err
+}
+
+func (f *float64Value) Get() any { return float64(*f) }
+
+func (f *float64Value) String() string { return strconv.FormatFloat(float64(*f), 'g', -1, 64) }
+
+// -- time.Duration Value
+type durationValue time.Duration
+
+func newDurationValue(val time.Duration, p *time.Duration) *durationValue {
+	*p = val
+	return (*durationValue)(p)
+}
+
+func (d *durationValue) Set(s string) error {
+	v, err := time.ParseDuration(s)
+	if err != nil {
+		err = errParse
+	}
+	*d = durationValue(v)
+	return err
+}
+
+func (d *durationValue) Get() any { return time.Duration(*d) }
+
+func (d *durationValue) String() string { return (*time.Duration)(d).String() }
+
+type funcValue func(string) error
+
+func (f funcValue) Set(s string) error { return f(s) }
+
+func (f funcValue) String() string { return "" }
+
+// Value is the interface to the dynamic value stored in a flag.
+// (The default value is represented as a string.)
+//
+// If a Value has an IsBoolFlag() bool method returning true,
+// the command-line parser makes -name equivalent to -name=true
+// rather than using the next command-line argument.
+//
+// Set is called once, in command line order, for each flag present.
+// The flag package may call the String method with a zero-valued receiver,
+// such as a nil pointer.
+type Value interface {
+	String() string
+	Set(string) error
+}
+
+// Getter is an interface that allows the contents of a Value to be retrieved.
+// It wraps the Value interface, rather than being part of it, because it
+// appeared after Go 1 and its compatibility rules. All Value types provided
+// by this package satisfy the Getter interface, except the type used by Func.
+type Getter interface {
+	Value
+	Get() any
+}
+
+// ErrorHandling defines how FlagSet.Parse behaves if the parse fails.
+type ErrorHandling int
+
+// These constants cause FlagSet.Parse to behave as described if the parse fails.
+const (
+	ContinueOnError ErrorHandling = iota // Return a descriptive error.
+	ExitOnError                          // Call os.Exit(2) or for -h/-help Exit(0).
+	PanicOnError                         // Call panic with a descriptive error.
+)
+
+// A FlagSet represents a set of defined flags. The zero value of a FlagSet
+// has no name and has ContinueOnError error handling.
+//
+// Flag names must be unique within a FlagSet. An attempt to define a flag whose
+// name is already in use will cause a panic.
+type FlagSet struct {
+	// Usage is the function called when an error occurs while parsing flags.
+	// The field is a function (not a method) that may be changed to point to
+	// a custom error handler. What happens after Usage is called depends
+	// on the ErrorHandling setting; for the command line, this defaults
+	// to ExitOnError, which exits the program after calling Usage.
+	Usage func()
+
+	name          string
+	parsed        bool
+	actual        map[string]*Flag
+	formal        map[string]*Flag
+	args          []string // arguments after flags
+	errorHandling ErrorHandling
+	output        io.Writer // nil means stderr; use Output() accessor
+}
+
+// A Flag represents the state of a flag.
+type Flag struct {
+	Name     string // name as it appears on command line
+	Usage    string // help message
+	Value    Value  // value as set
+	DefValue string // default value (as text); for usage message
+}
+
+// sortFlags returns the flags as a slice in lexicographical sorted order.
+func sortFlags(flags map[string]*Flag) []*Flag {
+	result := make([]*Flag, len(flags))
+	i := 0
+	for _, f := range flags {
+		result[i] = f
+		i++
+	}
+	sort.Slice(result, func(i, j int) bool {
+		return result[i].Name < result[j].Name
+	})
+	return result
+}
+
+// Output returns the destination for usage and error messages. os.Stderr is returned if
+// output was not set or was set to nil.
+func (f *FlagSet) Output() io.Writer {
+	if f.output == nil {
+		return os.Stderr
+	}
+	return f.output
+}
+
+// Name returns the name of the flag set.
+func (f *FlagSet) Name() string {
+	return f.name
+}
+
+// ErrorHandling returns the error handling behavior of the flag set.
+func (f *FlagSet) ErrorHandling() ErrorHandling {
+	return f.errorHandling
+}
+
+// SetOutput sets the destination for usage and error messages.
+// If output is nil, os.Stderr is used.
+func (f *FlagSet) SetOutput(output io.Writer) {
+	f.output = output
+}
+
+// VisitAll visits the flags in lexicographical order, calling fn for each.
+// It visits all flags, even those not set.
+func (f *FlagSet) VisitAll(fn func(*Flag)) {
+	for _, flag := range sortFlags(f.formal) {
+		fn(flag)
+	}
+}
+
+// VisitAll visits the command-line flags in lexicographical order, calling
+// fn for each. It visits all flags, even those not set.
+func VisitAll(fn func(*Flag)) {
+	CommandLine.VisitAll(fn)
+}
+
+// Visit visits the flags in lexicographical order, calling fn for each.
+// It visits only those flags that have been set.
+func (f *FlagSet) Visit(fn func(*Flag)) {
+	for _, flag := range sortFlags(f.actual) {
+		fn(flag)
+	}
+}
+
+// Visit visits the command-line flags in lexicographical order, calling fn
+// for each. It visits only those flags that have been set.
+func Visit(fn func(*Flag)) {
+	CommandLine.Visit(fn)
+}
+
+// Lookup returns the Flag structure of the named flag, returning nil if none exists.
+func (f *FlagSet) Lookup(name string) *Flag {
+	return f.formal[name]
+}
+
+// Lookup returns the Flag structure of the named command-line flag,
+// returning nil if none exists.
+func Lookup(name string) *Flag {
+	return CommandLine.formal[name]
+}
+
+// Set sets the value of the named flag.
+func (f *FlagSet) Set(name, value string) error {
+	flag, ok := f.formal[name]
+	if !ok {
+		return fmt.Errorf("no such flag -%v", name)
+	}
+	err := flag.Value.Set(value)
+	if err != nil {
+		return err
+	}
+	if f.actual == nil {
+		f.actual = make(map[string]*Flag)
+	}
+	f.actual[name] = flag
+	return nil
+}
+
+// Set sets the value of the named command-line flag.
+func Set(name, value string) error {
+	return CommandLine.Set(name, value)
+}
+
+// isZeroValue determines whether the string represents the zero
+// value for a flag.
+func isZeroValue(flag *Flag, value string) bool {
+	// Build a zero value of the flag's Value type, and see if the
+	// result of calling its String method equals the value passed in.
+	// This works unless the Value type is itself an interface type.
+	typ := reflect.TypeOf(flag.Value)
+	var z reflect.Value
+	if typ.Kind() == reflect.Pointer {
+		z = reflect.New(typ.Elem())
+	} else {
+		z = reflect.Zero(typ)
+	}
+	return value == z.Interface().(Value).String()
+}
+
+// UnquoteUsage extracts a back-quoted name from the usage
+// string for a flag and returns it and the un-quoted usage.
+// Given "a `name` to show" it returns ("name", "a name to show").
+// If there are no back quotes, the name is an educated guess of the
+// type of the flag's value, or the empty string if the flag is boolean.
+func UnquoteUsage(flag *Flag) (name string, usage string) {
+	// Look for a back-quoted name, but avoid the strings package.
+	usage = flag.Usage
+	for i := 0; i < len(usage); i++ {
+		if usage[i] == '`' {
+			for j := i + 1; j < len(usage); j++ {
+				if usage[j] == '`' {
+					name = usage[i+1 : j]
+					usage = usage[:i] + name + usage[j+1:]
+					return name, usage
+				}
+			}
+			break // Only one back quote; use type name.
+		}
+	}
+	// No explicit name, so use type if we can find one.
+	name = "value"
+	switch flag.Value.(type) {
+	case boolFlag:
+		name = ""
+	case *durationValue:
+		name = "duration"
+	case *float64Value:
+		name = "float"
+	case *intValue, *int64Value:
+		name = "int"
+	case *stringValue:
+		name = "string"
+	case *uintValue, *uint64Value:
+		name = "uint"
+	}
+	return
+}
+
+// PrintDefaults prints, to standard error unless configured otherwise, the
+// default values of all defined command-line flags in the set. See the
+// documentation for the global function PrintDefaults for more information.
+func (f *FlagSet) PrintDefaults() {
+	f.VisitAll(func(flag *Flag) {
+		var b strings.Builder
+		fmt.Fprintf(&b, "  -%s", flag.Name) // Two spaces before -; see next two comments.
+		name, usage := UnquoteUsage(flag)
+		if len(name) > 0 {
+			b.WriteString(" ")
+			b.WriteString(name)
+		}
+		// Boolean flags of one ASCII letter are so common we
+		// treat them specially, putting their usage on the same line.
+		if b.Len() <= 4 { // space, space, '-', 'x'.
+			b.WriteString("\t")
+		} else {
+			// Four spaces before the tab triggers good alignment
+			// for both 4- and 8-space tab stops.
+			b.WriteString("\n    \t")
+		}
+		b.WriteString(strings.ReplaceAll(usage, "\n", "\n    \t"))
+
+		if !isZeroValue(flag, flag.DefValue) {
+			if _, ok := flag.Value.(*stringValue); ok {
+				// put quotes on the value
+				fmt.Fprintf(&b, " (default %q)", flag.DefValue)
+			} else {
+				fmt.Fprintf(&b, " (default %v)", flag.DefValue)
+			}
+		}
+		fmt.Fprint(f.Output(), b.String(), "\n")
+	})
+}
+
+// PrintDefaults prints, to standard error unless configured otherwise,
+// a usage message showing the default settings of all defined
+// command-line flags.
+// For an integer valued flag x, the default output has the form
+//	-x int
+//		usage-message-for-x (default 7)
+// The usage message will appear on a separate line for anything but
+// a bool flag with a one-byte name. For bool flags, the type is
+// omitted and if the flag name is one byte the usage message appears
+// on the same line. The parenthetical default is omitted if the
+// default is the zero value for the type. The listed type, here int,
+// can be changed by placing a back-quoted name in the flag's usage
+// string; the first such item in the message is taken to be a parameter
+// name to show in the message and the back quotes are stripped from
+// the message when displayed. For instance, given
+//	flag.String("I", "", "search `directory` for include files")
+// the output will be
+//	-I directory
+//		search directory for include files.
+//
+// To change the destination for flag messages, call CommandLine.SetOutput.
+func PrintDefaults() {
+	CommandLine.PrintDefaults()
+}
+
+// defaultUsage is the default function to print a usage message.
+func (f *FlagSet) defaultUsage() {
+	if f.name == "" {
+		fmt.Fprintf(f.Output(), "Usage:\n")
+	} else {
+		fmt.Fprintf(f.Output(), "Usage of %s:\n", f.name)
+	}
+	f.PrintDefaults()
+}
+
+// NOTE: Usage is not just defaultUsage(CommandLine)
+// because it serves (via godoc flag Usage) as the example
+// for how to write your own usage function.
+
+// Usage prints a usage message documenting all defined command-line flags
+// to CommandLine's output, which by default is os.Stderr.
+// It is called when an error occurs while parsing flags.
+// The function is a variable that may be changed to point to a custom function.
+// By default it prints a simple header and calls PrintDefaults; for details about the
+// format of the output and how to control it, see the documentation for PrintDefaults.
+// Custom usage functions may choose to exit the program; by default exiting
+// happens anyway as the command line's error handling strategy is set to
+// ExitOnError.
+var Usage = func() {
+	fmt.Fprintf(CommandLine.Output(), "Usage of %s:\n", os.Args[0])
+	PrintDefaults()
+}
+
+// NFlag returns the number of flags that have been set.
+func (f *FlagSet) NFlag() int { return len(f.actual) }
+
+// NFlag returns the number of command-line flags that have been set.
+func NFlag() int { return len(CommandLine.actual) }
+
+// Arg returns the i'th argument. Arg(0) is the first remaining argument
+// after flags have been processed. Arg returns an empty string if the
+// requested element does not exist.
+func (f *FlagSet) Arg(i int) string {
+	if i < 0 || i >= len(f.args) {
+		return ""
+	}
+	return f.args[i]
+}
+
+// Arg returns the i'th command-line argument. Arg(0) is the first remaining argument
+// after flags have been processed. Arg returns an empty string if the
+// requested element does not exist.
+func Arg(i int) string {
+	return CommandLine.Arg(i)
+}
+
+// NArg is the number of arguments remaining after flags have been processed.
+func (f *FlagSet) NArg() int { return len(f.args) }
+
+// NArg is the number of arguments remaining after flags have been processed.
+func NArg() int { return len(CommandLine.args) }
+
+// Args returns the non-flag arguments.
+func (f *FlagSet) Args() []string { return f.args }
+
+// Args returns the non-flag command-line arguments.
+func Args() []string { return CommandLine.args }
+
+// BoolVar defines a bool flag with specified name, default value, and usage string.
+// The argument p points to a bool variable in which to store the value of the flag.
+func (f *FlagSet) BoolVar(p *bool, name string, value bool, usage string) {
+	f.Var(newBoolValue(value, p), name, usage)
+}
+
+// BoolVar defines a bool flag with specified name, default value, and usage string.
+// The argument p points to a bool variable in which to store the value of the flag.
+func BoolVar(p *bool, name string, value bool, usage string) {
+	CommandLine.Var(newBoolValue(value, p), name, usage)
+}
+
+// Bool defines a bool flag with specified name, default value, and usage string.
+// The return value is the address of a bool variable that stores the value of the flag.
+func (f *FlagSet) Bool(name string, value bool, usage string) *bool {
+	p := new(bool)
+	f.BoolVar(p, name, value, usage)
+	return p
+}
+
+// Bool defines a bool flag with specified name, default value, and usage string.
+// The return value is the address of a bool variable that stores the value of the flag.
+func Bool(name string, value bool, usage string) *bool {
+	return CommandLine.Bool(name, value, usage)
+}
+
+// IntVar defines an int flag with specified name, default value, and usage string.
+// The argument p points to an int variable in which to store the value of the flag.
+func (f *FlagSet) IntVar(p *int, name string, value int, usage string) {
+	f.Var(newIntValue(value, p), name, usage)
+}
+
+// IntVar defines an int flag with specified name, default value, and usage string.
+// The argument p points to an int variable in which to store the value of the flag.
+func IntVar(p *int, name string, value int, usage string) {
+	CommandLine.Var(newIntValue(value, p), name, usage)
+}
+
+// Int defines an int flag with specified name, default value, and usage string.
+// The return value is the address of an int variable that stores the value of the flag.
+func (f *FlagSet) Int(name string, value int, usage string) *int {
+	p := new(int)
+	f.IntVar(p, name, value, usage)
+	return p
+}
+
+// Int defines an int flag with specified name, default value, and usage string.
+// The return value is the address of an int variable that stores the value of the flag.
+func Int(name string, value int, usage string) *int {
+	return CommandLine.Int(name, value, usage)
+}
+
+// Int64Var defines an int64 flag with specified name, default value, and usage string.
+// The argument p points to an int64 variable in which to store the value of the flag.
+func (f *FlagSet) Int64Var(p *int64, name string, value int64, usage string) {
+	f.Var(newInt64Value(value, p), name, usage)
+}
+
+// Int64Var defines an int64 flag with specified name, default value, and usage string.
+// The argument p points to an int64 variable in which to store the value of the flag.
+func Int64Var(p *int64, name string, value int64, usage string) {
+	CommandLine.Var(newInt64Value(value, p), name, usage)
+}
+
+// Int64 defines an int64 flag with specified name, default value, and usage string.
+// The return value is the address of an int64 variable that stores the value of the flag.
+func (f *FlagSet) Int64(name string, value int64, usage string) *int64 {
+	p := new(int64)
+	f.Int64Var(p, name, value, usage)
+	return p
+}
+
+// Int64 defines an int64 flag with specified name, default value, and usage string.
+// The return value is the address of an int64 variable that stores the value of the flag.
+func Int64(name string, value int64, usage string) *int64 {
+	return CommandLine.Int64(name, value, usage)
+}
+
+// UintVar defines a uint flag with specified name, default value, and usage string.
+// The argument p points to a uint variable in which to store the value of the flag.
+func (f *FlagSet) UintVar(p *uint, name string, value uint, usage string) {
+	f.Var(newUintValue(value, p), name, usage)
+}
+
+// UintVar defines a uint flag with specified name, default value, and usage string.
+// The argument p points to a uint variable in which to store the value of the flag.
+func UintVar(p *uint, name string, value uint, usage string) {
+	CommandLine.Var(newUintValue(value, p), name, usage)
+}
+
+// Uint defines a uint flag with specified name, default value, and usage string.
+// The return value is the address of a uint variable that stores the value of the flag.
+func (f *FlagSet) Uint(name string, value uint, usage string) *uint {
+	p := new(uint)
+	f.UintVar(p, name, value, usage)
+	return p
+}
+
+// Uint defines a uint flag with specified name, default value, and usage string.
+// The return value is the address of a uint variable that stores the value of the flag.
+func Uint(name string, value uint, usage string) *uint {
+	return CommandLine.Uint(name, value, usage)
+}
+
+// Uint64Var defines a uint64 flag with specified name, default value, and usage string.
+// The argument p points to a uint64 variable in which to store the value of the flag.
+func (f *FlagSet) Uint64Var(p *uint64, name string, value uint64, usage string) {
+	f.Var(newUint64Value(value, p), name, usage)
+}
+
+// Uint64Var defines a uint64 flag with specified name, default value, and usage string.
+// The argument p points to a uint64 variable in which to store the value of the flag.
+func Uint64Var(p *uint64, name string, value uint64, usage string) {
+	CommandLine.Var(newUint64Value(value, p), name, usage)
+}
+
+// Uint64 defines a uint64 flag with specified name, default value, and usage string.
+// The return value is the address of a uint64 variable that stores the value of the flag.
+func (f *FlagSet) Uint64(name string, value uint64, usage string) *uint64 {
+	p := new(uint64)
+	f.Uint64Var(p, name, value, usage)
+	return p
+}
+
+// Uint64 defines a uint64 flag with specified name, default value, and usage string.
+// The return value is the address of a uint64 variable that stores the value of the flag.
+func Uint64(name string, value uint64, usage string) *uint64 {
+	return CommandLine.Uint64(name, value, usage)
+}
+
+// StringVar defines a string flag with specified name, default value, and usage string.
+// The argument p points to a string variable in which to store the value of the flag.
+func (f *FlagSet) StringVar(p *string, name string, value string, usage string) {
+	f.Var(newStringValue(value, p), name, usage)
+}
+
+// StringVar defines a string flag with specified name, default value, and usage string.
+// The argument p points to a string variable in which to store the value of the flag.
+func StringVar(p *string, name string, value string, usage string) {
+	CommandLine.Var(newStringValue(value, p), name, usage)
+}
+
+// String defines a string flag with specified name, default value, and usage string.
+// The return value is the address of a string variable that stores the value of the flag.
+func (f *FlagSet) String(name string, value string, usage string) *string {
+	p := new(string)
+	f.StringVar(p, name, value, usage)
+	return p
+}
+
+// String defines a string flag with specified name, default value, and usage string.
+// The return value is the address of a string variable that stores the value of the flag.
+func String(name string, value string, usage string) *string {
+	return CommandLine.String(name, value, usage)
+}
+
+// Float64Var defines a float64 flag with specified name, default value, and usage string.
+// The argument p points to a float64 variable in which to store the value of the flag.
+func (f *FlagSet) Float64Var(p *float64, name string, value float64, usage string) {
+	f.Var(newFloat64Value(value, p), name, usage)
+}
+
+// Float64Var defines a float64 flag with specified name, default value, and usage string.
+// The argument p points to a float64 variable in which to store the value of the flag.
+func Float64Var(p *float64, name string, value float64, usage string) {
+	CommandLine.Var(newFloat64Value(value, p), name, usage)
+}
+
+// Float64 defines a float64 flag with specified name, default value, and usage string.
+// The return value is the address of a float64 variable that stores the value of the flag.
+func (f *FlagSet) Float64(name string, value float64, usage string) *float64 {
+	p := new(float64)
+	f.Float64Var(p, name, value, usage)
+	return p
+}
+
+// Float64 defines a float64 flag with specified name, default value, and usage string.
+// The return value is the address of a float64 variable that stores the value of the flag.
+func Float64(name string, value float64, usage string) *float64 {
+	return CommandLine.Float64(name, value, usage)
+}
+
+// DurationVar defines a time.Duration flag with specified name, default value, and usage string.
+// The argument p points to a time.Duration variable in which to store the value of the flag.
+// The flag accepts a value acceptable to time.ParseDuration.
+func (f *FlagSet) DurationVar(p *time.Duration, name string, value time.Duration, usage string) {
+	f.Var(newDurationValue(value, p), name, usage)
+}
+
+// DurationVar defines a time.Duration flag with specified name, default value, and usage string.
+// The argument p points to a time.Duration variable in which to store the value of the flag.
+// The flag accepts a value acceptable to time.ParseDuration.
+func DurationVar(p *time.Duration, name string, value time.Duration, usage string) {
+	CommandLine.Var(newDurationValue(value, p), name, usage)
+}
+
+// Duration defines a time.Duration flag with specified name, default value, and usage string.
+// The return value is the address of a time.Duration variable that stores the value of the flag.
+// The flag accepts a value acceptable to time.ParseDuration.
+func (f *FlagSet) Duration(name string, value time.Duration, usage string) *time.Duration {
+	p := new(time.Duration)
+	f.DurationVar(p, name, value, usage)
+	return p
+}
+
+// Duration defines a time.Duration flag with specified name, default value, and usage string.
+// The return value is the address of a time.Duration variable that stores the value of the flag.
+// The flag accepts a value acceptable to time.ParseDuration.
+func Duration(name string, value time.Duration, usage string) *time.Duration {
+	return CommandLine.Duration(name, value, usage)
+}
+
+// Func defines a flag with the specified name and usage string.
+// Each time the flag is seen, fn is called with the value of the flag.
+// If fn returns a non-nil error, it will be treated as a flag value parsing error.
+func (f *FlagSet) Func(name, usage string, fn func(string) error) {
+	f.Var(funcValue(fn), name, usage)
+}
+
+// Func defines a flag with the specified name and usage string.
+// Each time the flag is seen, fn is called with the value of the flag.
+// If fn returns a non-nil error, it will be treated as a flag value parsing error.
+func Func(name, usage string, fn func(string) error) {
+	CommandLine.Func(name, usage, fn)
+}
+
+// Var defines a flag with the specified name and usage string. The type and
+// value of the flag are represented by the first argument, of type Value, which
+// typically holds a user-defined implementation of Value. For instance, the
+// caller could create a flag that turns a comma-separated string into a slice
+// of strings by giving the slice the methods of Value; in particular, Set would
+// decompose the comma-separated string into the slice.
+func (f *FlagSet) Var(value Value, name string, usage string) {
+	// Flag must not begin "-" or contain "=".
+	if strings.HasPrefix(name, "-") {
+		panic(f.sprintf("flag %q begins with -", name))
+	} else if strings.Contains(name, "=") {
+		panic(f.sprintf("flag %q contains =", name))
+	}
+
+	// Remember the default value as a string; it won't change.
+	flag := &Flag{name, usage, value, value.String()}
+	_, alreadythere := f.formal[name]
+	if alreadythere {
+		var msg string
+		if f.name == "" {
+			msg = f.sprintf("flag redefined: %s", name)
+		} else {
+			msg = f.sprintf("%s flag redefined: %s", f.name, name)
+		}
+		panic(msg) // Happens only if flags are declared with identical names
+	}
+	if f.formal == nil {
+		f.formal = make(map[string]*Flag)
+	}
+	f.formal[name] = flag
+}
+
+// Var defines a flag with the specified name and usage string. The type and
+// value of the flag are represented by the first argument, of type Value, which
+// typically holds a user-defined implementation of Value. For instance, the
+// caller could create a flag that turns a comma-separated string into a slice
+// of strings by giving the slice the methods of Value; in particular, Set would
+// decompose the comma-separated string into the slice.
+func Var(value Value, name string, usage string) {
+	CommandLine.Var(value, name, usage)
+}
+
+// sprintf formats the message, prints it to output, and returns it.
+func (f *FlagSet) sprintf(format string, a ...any) string {
+	msg := fmt.Sprintf(format, a...)
+	fmt.Fprintln(f.Output(), msg)
+	return msg
+}
+
+// failf prints to standard error a formatted error and usage message and
+// returns the error.
+func (f *FlagSet) failf(format string, a ...any) error {
+	msg := f.sprintf(format, a...)
+	f.usage()
+	return errors.New(msg)
+}
+
+// usage calls the Usage method for the flag set if one is specified,
+// or the appropriate default usage function otherwise.
+func (f *FlagSet) usage() {
+	if f.Usage == nil {
+		f.defaultUsage()
+	} else {
+		f.Usage()
+	}
+}
+
+// parseOne parses one flag. It reports whether a flag was seen.
+func (f *FlagSet) parseOne() (bool, error) {
+	if len(f.args) == 0 {
+		return false, nil
+	}
+	s := f.args[0]
+	if len(s) < 2 || s[0] != '-' {
+		return false, nil
+	}
+	numMinuses := 1
+	if s[1] == '-' {
+		numMinuses++
+		if len(s) == 2 { // "--" terminates the flags
+			f.args = f.args[1:]
+			return false, nil
+		}
+	}
+	name := s[numMinuses:]
+	if len(name) == 0 || name[0] == '-' || name[0] == '=' {
+		return false, f.failf("bad flag syntax: %s", s)
+	}
+
+	// it's a flag. does it have an argument?
+	f.args = f.args[1:]
+	hasValue := false
+	value := ""
+	for i := 1; i < len(name); i++ { // equals cannot be first
+		if name[i] == '=' {
+			value = name[i+1:]
+			hasValue = true
+			name = name[0:i]
+			break
+		}
+	}
+	m := f.formal
+	flag, alreadythere := m[name] // BUG
+	if !alreadythere {
+		if name == "help" || name == "h" { // special case for nice help message.
+			f.usage()
+			return false, ErrHelp
+		}
+		return false, f.failf("flag provided but not defined: -%s", name)
+	}
+
+	if fv, ok := flag.Value.(boolFlag); ok && fv.IsBoolFlag() { // special case: doesn't need an arg
+		if hasValue {
+			if err := fv.Set(value); err != nil {
+				return false, f.failf("invalid boolean value %q for -%s: %v", value, name, err)
+			}
+		} else {
+			if err := fv.Set("true"); err != nil {
+				return false, f.failf("invalid boolean flag %s: %v", name, err)
+			}
+		}
+	} else {
+		// It must have a value, which might be the next argument.
+		if !hasValue && len(f.args) > 0 {
+			// value is the next arg
+			hasValue = true
+			value, f.args = f.args[0], f.args[1:]
+		}
+		if !hasValue {
+			return false, f.failf("flag needs an argument: -%s", name)
+		}
+		if err := flag.Value.Set(value); err != nil {
+			return false, f.failf("invalid value %q for flag -%s: %v", value, name, err)
+		}
+	}
+	if f.actual == nil {
+		f.actual = make(map[string]*Flag)
+	}
+	f.actual[name] = flag
+	return true, nil
+}
+
+// Parse parses flag definitions from the argument list, which should not
+// include the command name. Must be called after all flags in the FlagSet
+// are defined and before flags are accessed by the program.
+// The return value will be ErrHelp if -help or -h were set but not defined.
+func (f *FlagSet) Parse(arguments []string) error {
+	f.parsed = true
+	f.args = arguments
+	for {
+		seen, err := f.parseOne()
+		if seen {
+			continue
+		}
+		if err == nil {
+			break
+		}
+		switch f.errorHandling {
+		case ContinueOnError:
+			return err
+		case ExitOnError:
+			if err == ErrHelp {
+				os.Exit(0)
+			}
+			os.Exit(2)
+		case PanicOnError:
+			panic(err)
+		}
+	}
+	return nil
+}
+
+// Parsed reports whether f.Parse has been called.
+func (f *FlagSet) Parsed() bool {
+	return f.parsed
+}
+
+// Parse parses the command-line flags from os.Args[1:]. Must be called
+// after all flags are defined and before flags are accessed by the program.
+func Parse() {
+	// Ignore errors; CommandLine is set for ExitOnError.
+	CommandLine.Parse(os.Args[1:])
+}
+
+// Parsed reports whether the command-line flags have been parsed.
+func Parsed() bool {
+	return CommandLine.Parsed()
+}
+
+// CommandLine is the default set of command-line flags, parsed from os.Args.
+// The top-level functions such as BoolVar, Arg, and so on are wrappers for the
+// methods of CommandLine.
+var CommandLine = NewFlagSet(os.Args[0], ExitOnError)
+
+func init() {
+	// Override generic FlagSet default Usage with call to global Usage.
+	// Note: This is not CommandLine.Usage = Usage,
+	// because we want any eventual call to use any updated value of Usage,
+	// not the value it has when this line is run.
+	CommandLine.Usage = commandLineUsage
+}
+
+func commandLineUsage() {
+	Usage()
+}
+
+// NewFlagSet returns a new, empty flag set with the specified name and
+// error handling property. If the name is not empty, it will be printed
+// in the default usage message and in error messages.
+func NewFlagSet(name string, errorHandling ErrorHandling) *FlagSet {
+	f := &FlagSet{
+		name:          name,
+		errorHandling: errorHandling,
+	}
+	f.Usage = f.defaultUsage
+	return f
+}
+
+// Init sets the name and error handling property for a flag set.
+// By default, the zero FlagSet uses an empty name and the
+// ContinueOnError error handling policy.
+func (f *FlagSet) Init(name string, errorHandling ErrorHandling) {
+	f.name = name
+	f.errorHandling = errorHandling
+}