Documentation

Overview

Package multiflag is a package providing a flag.Value implementation capable of switching between multiple registered sub-flags, each of which have their own set of parameter flags.

Example

This can be used to construct complex option flags. For example:

-backend mysql,address="192.168.1.1",port="12345"
-backend sqlite3,path="/path/to/database"

In this example, a MultiFlag is defined and bound to the option name, "backend". This MultiFlag has (at least) two registered Options:

1) mysql, whose FlagSet binds "address" and "port" options.
2) sqlite3, whose FlagSet binds "path".

The MultiFlag Option that is selected (e.g., "mysql") has the remainder of its option string parsed into its FlagSet, populating its "address" and "port" parameters. If "sqlite3" is selected, the remainder of the option string would be parsed into its FlagSet, which hosts the "path" parameter.

Index

Examples

Constants

This section is empty.

Variables

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Functions

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Types

type FlagOption

type FlagOption struct {
	Name        string
	Description string
	Pinned      bool
	// contains filtered or unexported fields
}

    FlagOption is an implementation of Option that is describes a single nestedflagset option. This option has sub-properties that

    func (*FlagOption) Descriptor

    func (o *FlagOption) Descriptor() *OptionDescriptor

      Descriptor implements Option.

      func (*FlagOption) Flags

      func (o *FlagOption) Flags() *flag.FlagSet

        Flags returns this Option's nested FlagSet for configuration.

        func (*FlagOption) IsPinned

        func (o *FlagOption) IsPinned() bool

          IsPinned implements Option.

          func (*FlagOption) PrintHelp

          func (o *FlagOption) PrintHelp(output io.Writer)

            PrintHelp implements Option.

            func (*FlagOption) Run

            func (o *FlagOption) Run(value string) error

              Run implements Option.

              type MultiFlag

              type MultiFlag struct {
              	Description string
              	Options     []Option
              	Output      io.Writer // Output writer, or nil to use STDERR.
              
              	// The selected Option, populated after Parsing.
              	Selected Option
              }

                MultiFlag is a flag.Value-like object that contains multiple sub-options. Each sub-option presents itself as a flag.FlagSet. The sub-option that gets selected will have its FlagSet be evaluated against the accompanying options.

                For example, one can construct flag that, depending on its options, chooses one of two sets of sub-properties:

                -myflag foo,foovalue=123
                -myflag bar,barvalue=456,barothervalue="hello"
                

                "myflag" is the name of the MultiFlag's top-level flag, as registered with a flag.FlagSet. The first token in the flag's value selects which Option should be configured. If "foo" is configured, the remaining configuration is parsed by the "foo" Option's FlagSet, and the equivalent is true for "bar".

                Example
                Output:
                
                Selecting help option: [-multiflag help]
                My test MultiFlag.
                help        Displays this help message. Can be run as "help,<option>" to display help for an option.
                beta        The new option, which is still beta.
                deprecated  The deprecated option.
                Selecting beta option: [-multiflag beta,param=Sup]
                Option [beta], parameter: [Sup].
                

                func (*MultiFlag) GetOptionFor

                func (mf *MultiFlag) GetOptionFor(name string) Option

                  GetOptionFor returns the Option associated with the specified name, or nil if one isn't defined.

                  func (*MultiFlag) GetOutput

                  func (mf *MultiFlag) GetOutput() io.Writer

                    GetOutput returns the output Writer used for help output.

                    func (MultiFlag) OptionNames

                    func (mf MultiFlag) OptionNames() []string

                      OptionNames returns a list of the option names registered with a MultiFlag.

                      func (*MultiFlag) Parse

                      func (mf *MultiFlag) Parse(value string) error

                        Parse applies a value string to a MultiFlag.

                        For example, if the value string is: foo,option1=test

                        Parse will identify the MultiFlag option named "foo" and have it parse the string, "option1=test".

                        func (*MultiFlag) PrintHelp

                        func (mf *MultiFlag) PrintHelp() error

                          PrintHelp prints a formatted help string for a MultiFlag. This help string details the Options registered with the MultiFlag.

                          func (*MultiFlag) Set

                          func (mf *MultiFlag) Set(value string) error

                            Set implements flag.Value

                            func (*MultiFlag) String

                            func (mf *MultiFlag) String() string

                              String implements flag.Value

                              type Option

                              type Option interface {
                              	Descriptor() *OptionDescriptor
                              
                              	PrintHelp(io.Writer)
                              	Run(string) error // Parses the Option from a configuration string.
                              }

                                Option is a single option entry in a MultiFlag. An Option is responsible for parsing a FlagSet from an option string.

                                func HelpOption

                                func HelpOption(mf *MultiFlag) Option

                                  HelpOption instantiates a new Option instance that prints a help string when parsed.

                                  type OptionDescriptor

                                  type OptionDescriptor struct {
                                  	Name        string
                                  	Description string
                                  
                                  	Pinned bool
                                  }

                                    OptionDescriptor is a collection of common Option properties.

                                    Source Files