gflag

package
v0.5.5 Latest Latest
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 Go to latest Published: Oct 28, 2018 License: BSD-3-Clause Imports: 7 Imported by: 0

Documentation

Overview

Package gflag implements GNU-style command line flag parsing. It supports the transformation of programs using the Go standard library flag package. However it doesn't target full compatibility with the Go standard library flag package. The Flag structure doesn't support all fields of the flag package and the Var method and function does have a different signature.

The typical use case looks like this: 

  b := Bool("flag-b", "b", false, "boolean flag")
  h := Bool("help", "h", false, "prints this message")

  Parse()

  if *h {
	  gflag.Usage()
  }

Index

Constants

This section is empty.

Variables

View Source 
var CommandLine = NewFlagSet(os.Args[0], ExitOnError)

CommandLine is the default set of command-line flags parsed from os.Args. The top-level functions such as BoolVar, Arg, etc. are wrappers for the methods of command line.

View Source 
var Usage = func() {
	fmt.Fprintf(CommandLine.out(), "Usage of %s:\n", os.Args[0])
	PrintDefaults()
}

Usage prints the default usage message.

Functions

func Arg 

func Arg(i int) string

Arg provides the argument number i after parsing of the command line flags.

func Args 

func Args() []string

Args returns all arguments after the command line flags have been parsed.

func Bool 

func Bool(name string, value bool, usage string) *bool

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 BoolP 

func BoolP(name, shorthands string, value bool, usage string) *bool

BoolP defines a bool flag with specified name, shorthands, default value and usage string. The return value is the address of a bool variable that stores the value of the flag.

func BoolVar 

func BoolVar(p *bool, name string, value bool, usage string)

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 BoolVarP 

func BoolVarP(p *bool, name, shorthands string, value bool, usage string)

BoolVarP defines a bool flag with specified name, shorthands, default value and usage string. The argument p points to a bool variable in which to store the value of the flag.

func Counter 

func Counter(name string, value int, usage string) *int

Counter defines a counter flag with specified name, default value and usage string. The return value is the address of an integer variable that stores the value of the flag.

func CounterP 

func CounterP(name, shorthands string, value int, usage string) *int

CounterP defines a counter flag with specified name, shorthands, default value and usage string. The return value is the address of an integer variable that stores the value of the flag.

func CounterVar 

func CounterVar(p *int, name string, value int, usage string)

CounterVar defines a counter flag with specified name, default value and usage string. The argument p points to an integer variable in which to store the value of the flag.

func CounterVarP 

func CounterVarP(p *int, name, shorthands string, value int, usage string)

CounterVarP defines a counter flag with specified name, shorthands, default value and usage string. The argument p points to an integer variable in which to store the value of the flag.

func Int 

func Int(name string, value int, usage string) *int

Int defines an integer flag with specified name, default value and usage string. The return value is the address of an integer variable that stores the value of the flag.

func IntP 

func IntP(name, shorthands string, value int, usage string) *int

IntP defines an integer flag with specified name, shorthands, default value and usage string. The return value is the address of an integer variable that stores the value of the flag.

func IntVar 

func IntVar(p *int, name string, value int, usage string)

IntVar defines an integer flag with specified name, default value and usage string. The argument p points to an integer variable in which to store the value of the flag.

func IntVarP 

func IntVarP(p *int, name, shorthands string, value int, usage string)

IntVarP defines an integer flag with specified name, shorthands, default value and usage string. The argument p points to an integer variable in which to store the value of the flag.

func NArg 

func NArg() int

NArg returns the number of remaining arguments after command line parsing.

func Parse 

func Parse()

Parse parses the command line.

func Parsed 

func Parsed() bool

Parsed returns whether the command line has already been parsed.

func Preset 

func Preset(start, end, value int, usage string) *int

Preset defines a range of preset flags starting at start and ending at end. The return value is the address of a preset variable in which to store the value of the flag.

If start is 1 and end is 9 the flags -1 to -9 will be supported.

func PresetVar 

func PresetVar(p *int, start, end, value int, usage string)

PresetVar defines a range of preset flags starting at start and ending at end. The argument p points to a preset variable in which to store the value of the flag.

If start is 1 and end is 9 the flags -1 to -9 will be supported.

func PrintDefaults 

func PrintDefaults()

PrintDefaults prints the information about all command line flags.

func String 

func String(name, value, usage string) *string

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 StringP 

func StringP(name, shorthands, value, usage string) *string

StringP defines a string flag with specified name, shorthands, default value and usage string. The return value is the address of a string variable that stores the value of the flag.

func StringVar 

func StringVar(p *string, name, value, usage string)

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 StringVarP 

func StringVarP(p *string, name, shorthands, value, usage string)

StringVarP defines an string flag with specified name, shorthands, default value and usage string. The argument p points to a string variable in which to store the value of the flag.

func Var 

func Var(value Value, name string, hasArg HasArg)

Var creates a flag for the given option name for the command line.

func VarP 

func VarP(value Value, name, shorthands string, hasArg HasArg)

VarP creates a flag for the given value for the command line.

Types

type ErrorHandling 

type ErrorHandling int

ErrorHandling defines how flag parsing errors are handled. 

const (
	ContinueOnError ErrorHandling = iota
	ExitOnError
	PanicOnError
)

The constants define how errors should be handled.

type Flag 

type Flag struct {
	Name       string
	Shorthands string
	HasArg     HasArg
	Value      Value
}

Flag represents a single flag.

type FlagSet 

type FlagSet struct {
	// Provides a custom usage function if set.
	Usage func()
	// contains filtered or unexported fields
}

FlagSet represents a set of option flags.

func NewFlagSet 

func NewFlagSet(name string, errorHandling ErrorHandling) *FlagSet

NewFlagSet creates a new flag set.

func (*FlagSet) Arg 

func (f *FlagSet) Arg(i int) string

Arg returns the argument number i after parsing has been successful.

func (*FlagSet) Args 

func (f *FlagSet) Args() []string

Args returns all arguments after parsing.

func (*FlagSet) Bool 

func (f *FlagSet) Bool(name string, value bool, usage string) *bool

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 (*FlagSet) BoolP 

func (f *FlagSet) BoolP(name, shorthands string, value bool, usage string) *bool

BoolP defines a bool flag with specified name, shorthands, default value and usage string. The return value is the address of a bool variable that stores the value of the flag.

func (*FlagSet) BoolVar 

func (f *FlagSet) BoolVar(p *bool, name string, value bool, usage string)

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 (*FlagSet) BoolVarP 

func (f *FlagSet) BoolVarP(p *bool, name, shorthands string, value bool, usage string)

BoolVarP defines a bool flag with specified name, shorthands, default value and usage string. The argument p points to a bool variable in which to store the value of the flag.

func (*FlagSet) Counter 

func (f *FlagSet) Counter(name string, value int, usage string) *int

Counter defines a counter flag with specified name, default value and usage string. The return value is the address of an integer variable that stores the value of the flag.

func (*FlagSet) CounterP 

func (f *FlagSet) CounterP(name, shorthands string, value int, usage string) *int

CounterP defines a counter flag with specified name, shorthands, default value and usage string. The return value is the address of an integer variable that stores the value of the flag.

func (*FlagSet) CounterVar 

func (f *FlagSet) CounterVar(p *int, name string, value int, usage string)

CounterVar defines a counter flag with specified name, default value and usage string. The argument p points to an integer variable in which to store the value of the flag.

func (*FlagSet) CounterVarP 

func (f *FlagSet) CounterVarP(p *int, name, shorthands string, value int, usage string)

CounterVarP defines a counter flag with specified name, shorthands, default value and usage string. The argument p points to an integer variable in which to store the value of the flag.

func (*FlagSet) Init 

func (f *FlagSet) Init(name string, errorHandling ErrorHandling)

Init initializes a flag set variable.

func (*FlagSet) Int 

func (f *FlagSet) Int(name string, value int, usage string) *int

Int defines an integer flag with specified name, default value and usage string. The return value is the address of an integer variable that stores the value of the flag.

func (*FlagSet) IntP 

func (f *FlagSet) IntP(name, shorthands string, value int, usage string) *int

IntP defines an integer flag with specified name, shorthands, default value and usage string. The return value is the address of an integer variable that stores the value of the flag.

func (*FlagSet) IntVar 

func (f *FlagSet) IntVar(p *int, name string, value int, usage string)

IntVar defines an integer flag with specified name, default value and usage string. The argument p points to an integer variable in which to store the value of the flag.

func (*FlagSet) IntVarP 

func (f *FlagSet) IntVarP(p *int, name, shorthands string, value int, usage string)

IntVarP defines an integer flag with specified name, shorthands, default value and usage string. The argument p points to an integer variable in which to store the value of the flag.

func (*FlagSet) NArg 

func (f *FlagSet) NArg() int

NArg returns the number of remaining arguments after parsing.

func (*FlagSet) Parse 

func (f *FlagSet) Parse(arguments []string) error

Parse parses the arguments. If an error happens the error is printed as well as the usage information.

func (*FlagSet) Parsed 

func (f *FlagSet) Parsed() bool

Parsed returns whether the flag set has already been parsed.

func (*FlagSet) Preset 

func (f *FlagSet) Preset(start, end, value int, usage string) *int

Preset defines a range of preset flags starting at start and ending at end. The return value is the address of a preset variable in which to store the value of the flag.

If start is 1 and end is 9 the flags -1 to -9 will be supported.

func (*FlagSet) PresetVar 

func (f *FlagSet) PresetVar(p *int, start, end, value int, usage string)

PresetVar defines a range of preset flags starting at start and ending at end. The argument p points to a preset variable in which to store the value of the flag.

If start is 1 and end is 9 the flags -1 to -9 will be supported.

func (*FlagSet) PrintDefaults 

func (f *FlagSet) PrintDefaults()

PrintDefaults prints information about all flags.

func (*FlagSet) SetOutput 

func (f *FlagSet) SetOutput(w io.Writer)

SetOutput sets the default output writer for the flag set.

func (*FlagSet) String 

func (f *FlagSet) String(name, value, usage string) *string

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 (*FlagSet) StringP 

func (f *FlagSet) StringP(name, shorthands, value, usage string) *string

StringP defines a string flag with specified name, shorthands, default value and usage string. The return value is the address of a string variable that stores the value of the flag.

func (*FlagSet) StringVar 

func (f *FlagSet) StringVar(p *string, name, value, usage string)

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 (*FlagSet) StringVarP 

func (f *FlagSet) StringVarP(p *string, name, shorthands, value, usage string)

StringVarP defines an string flag with specified name, shorthands, default value and usage string. The argument p points to a string variable in which to store the value of the flag.

func (*FlagSet) Var 

func (f *FlagSet) Var(value Value, name string, hasArg HasArg)

Var creates a flag for the given option name.

func (*FlagSet) VarP 

func (f *FlagSet) VarP(value Value, name, shorthands string, hasArg HasArg)

VarP creates a flag with a long and shorthand options.

type HasArg 

type HasArg int

HasArg defines whether a flag argument is required, optional or not supported. 

const (
	RequiredArg HasArg = iota
	NoArg
	OptionalArg
)

The constants define whether a flag argument is required, not supported or optional.

type Value 

type Value interface {
	Set(string) error
	Update()
	Get() interface{}
	String() string
}

Value is the interface to the value of a specific flag.

Source Files

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