wmenu

package module
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 Go to latest Published: Apr 15, 2017 License: MIT Imports: 10 Imported by: 0

README

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Package wmenu creates menus for cli programs. It uses wlog for it's interface with the command line. It uses os.Stdin, os.Stdout, and os.Stderr with concurrency by default. wmenu allows you to change the color of the different parts of the menu. This package also creates it's own error structure so you can type assert if you need to. wmenu will validate all responses before calling any function. It will also figure out which function should be called so you don't have to.

Import

import "github.com/dixonwille/wmenu"

Features

  • Force single selection
  • Allow multiple selection
  • Change the delimiter
  • Change the color of different parts of the menu
  • Easily see which option(s) are default
  • Change the symbol used for default option(s)
  • Ask simple yes and no questions
  • Validate all responses before calling any functions
  • With yes and no can accept:
    • yes, Yes, YES, y, Y
    • no, No, NO, n, N
  • Figure out which Action should be called (Options, Default, or Multiple Action)
  • Re-ask question if invalid response up to a certain number of times
  • Can change max number of times to ask before failing output
  • Change reader and writer
  • Clear the screen whenever the menu is brought up
  • Has its own error structure so you can type assert menu errors

Usage

This is a simple use of the package.

menu := wmenu.NewMenu("What is your favorite food?")
menu.Action(func (opt Opt) error {fmt.Printf(opt.Text + " is your favorite food."); return nil})
menu.Option("Pizza", true, nil)
menu.Option("Ice Cream", false, nil)
menu.Option("Tacos", false, func() error {
  fmt.Printf("Tacos are great")
})
err := menu.Run()
if err != nil{
  log.Fatal(err)
}

The output would look like this:

0) *Pizza
1) Ice Cream
2) Tacos
What is your favorite food?

If the user just presses [Enter] then the option(s) with the * will be selected. This indicates that it is a default function. If they choose 1 then they would see Ice Cream is your favorite food.. This used the Action's function because the option selected didn't have a function along with it. But if they choose 2 they would see Tacos are great. That option did have a function with it which take precedence over Action.

You can you also use:

menu.MultipleAction(func (opt []Opt) error {return nil})

This will allow the user to select multiple options. The default delimiter is a [space], but can be changed by using:

menu.SetSeperator("some string")

Another feature is the ability to ask yes or no questions.

menu.IsYesNo(0)

This will remove any options previously added options and hide the ones used for the menu. It will simply just ask yes or no. Menu will parse and validate the response for you. This option will always call the Action's function and pass in the option that was selected.

Further Reading

This whole package has been documented and has a few examples in the godocs. You should read the docs to find all functions and structures at your finger tips.

Documentation

Overview

Package wmenu creates menus for cli programs. It uses wlog for it's interface with the command line. It uses os.Stdin, os.Stdout, and os.Stderr with concurrency by default. wmenu allows you to change the color of the different parts of the menu. This package also creates it's own error structure so you can type assert if you need to. wmenu will validate all responses before calling any function. It will also figure out which function should be called so you don't have to.

Example (ErrorDuplicate) 
reader := strings.NewReader("1 1\r\n") //Simulates the user typing "1 1" and hitting the [enter] key
optFunc := func() error {
	fmt.Println("Option 0 was chosen.")
	return nil
}
multiFunc := func(opts []Opt) error {
	for _, opt := range opts {
		fmt.Printf("%s has an id of %d.\n", opt.Text, opt.ID)
	}
	return nil
}
menu := NewMenu("Choose an option.")
menu.ChangeReaderWriter(reader, os.Stdout, os.Stderr)
menu.MultipleAction(multiFunc)
menu.Option("Option 0", false, optFunc)
menu.Option("Option 1", false, nil)
menu.Option("Option 2", false, nil)
err := menu.Run()
if err != nil {
	if IsDuplicateErr(err) {
		fmt.Println("We caught the err: " + err.Error())
	} else {
		log.Fatal(err)
	}
}

Output:

0) Option 0
1) Option 1
2) Option 2
Choose an option.
We caught the err: Duplicated response: 1
Example (ErrorInvalid) 
reader := strings.NewReader("3\r\n") //Simulates the user typing "3" and hitting the [enter] key
optFunc := func() error {
	fmt.Println("Option 0 was chosen.")
	return nil
}
menu := NewMenu("Choose an option.")
menu.ChangeReaderWriter(reader, os.Stdout, os.Stderr)
menu.Option("Option 0", false, optFunc)
menu.Option("Option 1", false, nil)
menu.Option("Option 2", false, nil)
err := menu.Run()
if err != nil {
	if IsInvalidErr(err) {
		fmt.Println("We caught the err: " + err.Error())
	} else {
		log.Fatal(err)
	}
}

Output:

0) Option 0
1) Option 1
2) Option 2
Choose an option.
We caught the err: Invalid response: 3
Example (ErrorNoResponse) 
reader := strings.NewReader("\r\n") //Simulates the user hitting the [enter] key
optFunc := func() error {
	fmt.Println("Option 0 was chosen.")
	return nil
}
menu := NewMenu("Choose an option.")
menu.ChangeReaderWriter(reader, os.Stdout, os.Stderr)
menu.Option("Option 0", false, optFunc)
menu.Option("Option 1", false, nil)
menu.Option("Option 2", false, nil)
err := menu.Run()
if err != nil {
	if IsNoResponseErr(err) {
		fmt.Println("We caught the err: " + err.Error())
	} else {
		log.Fatal(err)
	}
}

Output:

0) Option 0
1) Option 1
2) Option 2
Choose an option.
We caught the err: No response
Example (ErrorTooMany) 
reader := strings.NewReader("1 2\r\n") //Simulates the user typing "1 2" and hitting the [enter] key
optFunc := func() error {
	fmt.Println("Option 0 was chosen.")
	return nil
}
menu := NewMenu("Choose an option.")
menu.ChangeReaderWriter(reader, os.Stdout, os.Stderr)
menu.Option("Option 0", false, optFunc)
menu.Option("Option 1", false, nil)
menu.Option("Option 2", false, nil)
err := menu.Run()
if err != nil {
	if IsTooManyErr(err) {
		fmt.Println("We caught the err: " + err.Error())
	} else {
		log.Fatal(err)
	}
}

Output:

0) Option 0
1) Option 1
2) Option 2
Choose an option.
We caught the err: Too many responses
Example (Multiple) 
reader := strings.NewReader("1,2\r\n") //Simulates the user typing "1,2" and hitting the [enter] key
optFunc := func() error {
	fmt.Println("Option 0 was chosen.")
	return nil
}
multiFunc := func(opts []Opt) error {
	for _, opt := range opts {
		fmt.Printf("%s has an id of %d.\n", opt.Text, opt.ID)
	}
	return nil
}
menu := NewMenu("Choose an option.")
menu.ChangeReaderWriter(reader, os.Stdout, os.Stderr)
menu.MultipleAction(multiFunc)
menu.SetSeparator(",")
menu.Option("Option 0", true, optFunc)
menu.Option("Option 1", false, nil)
menu.Option("Option 2", true, nil)
err := menu.Run()
if err != nil {
	log.Fatal(err)
}

Output:

0) *Option 0
1) Option 1
2) *Option 2
Choose an option.
Option 1 has an id of 1.
Option 2 has an id of 2.
Example (MultipleDefault) 
reader := strings.NewReader("\r\n") //Simulates the user hitting the [enter] key
optFunc := func() error {
	fmt.Println("Option 0 was chosen.")
	return nil
}
multiFunc := func(opts []Opt) error {
	for _, opt := range opts {
		fmt.Printf("%s has an id of %d.\n", opt.Text, opt.ID)
	}
	return nil
}
menu := NewMenu("Choose an option.")
menu.ChangeReaderWriter(reader, os.Stdout, os.Stderr)
menu.MultipleAction(multiFunc)
menu.Option("Option 0", true, optFunc)
menu.Option("Option 1", false, nil)
menu.Option("Option 2", true, nil)
err := menu.Run()
if err != nil {
	log.Fatal(err)
}

Output:

0) *Option 0
1) Option 1
2) *Option 2
Choose an option.
Option 0 has an id of 0.
Option 2 has an id of 2.
Example (Simple) 
reader := strings.NewReader("1\r\n") //Simulates the user typing "1" and hitting the [enter] key
optFunc := func() error {
	fmt.Println("Option 0 was chosen.")
	return nil
}
actFunc := func(opt Opt) error {
	fmt.Printf("%s has an id of %d.\n", opt.Text, opt.ID)
	return nil
}
menu := NewMenu("Choose an option.")
menu.ChangeReaderWriter(reader, os.Stdout, os.Stderr)
menu.Action(actFunc)
menu.Option("Option 0", true, optFunc)
menu.Option("Option 1", false, nil)
menu.Option("Option 2", true, nil)
err := menu.Run()
if err != nil {
	log.Fatal(err)
}

Output:

0) *Option 0
1) Option 1
2) *Option 2
Choose an option.
Option 1 has an id of 1.
Example (SimpleDefault) 
reader := strings.NewReader("\r\n") //Simulates the user hitting the [enter] key
optFunc := func() error {
	fmt.Fprint(os.Stdout, "Option 0 was chosen.")
	return nil
}
menu := NewMenu("Choose an option.")
menu.ChangeReaderWriter(reader, os.Stdout, os.Stderr)
menu.Option("Option 0", true, optFunc)
menu.Option("Option 1", false, nil)
menu.Option("Option 2", false, nil)
err := menu.Run()
if err != nil {
	log.Fatal(err)
}

Output:

0) *Option 0
1) Option 1
2) Option 2
Choose an option.
Option 0 was chosen.
Example (YesNo) 
reader := strings.NewReader("y\r\n") //Simulates the user typing "1" and hitting the [enter] key
actFunc := func(opt Opt) error {
	fmt.Printf("%s has an id of %d.\n", opt.Text, opt.ID)
	return nil
}
menu := NewMenu("Would you like to start?")
menu.ChangeReaderWriter(reader, os.Stdout, os.Stderr)
menu.Action(actFunc)
menu.IsYesNo(0)
err := menu.Run()
if err != nil {
	log.Fatal(err)
}

Output:

Would you like to start? (Y/n)
y has an id of 0.

Index

Examples

Constants

This section is empty.

Variables

View Source 
var (
	//ErrInvalid is returned if a response from user was an invalid option
	ErrInvalid = errors.New("Invalid response")

	//ErrTooMany is returned if multiSelect is false and a user tries to select multiple options
	ErrTooMany = errors.New("Too many responses")

	//ErrNoResponse is returned if there were no responses and no action to call
	ErrNoResponse = errors.New("No response")

	//ErrDuplicate is returned is a user selects an option twice
	ErrDuplicate = errors.New("Duplicated response")
)

Functions

func Clear 

func Clear()

Clear simply clears the command line interface (os.Stdout only).

func IsDuplicateErr 

func IsDuplicateErr(err error) bool

IsDuplicateErr checks to see if err is of type duplicate returned by menu.

func IsInvalidErr 

func IsInvalidErr(err error) bool

IsInvalidErr checks to see if err is of type invalid error returned by menu.

func IsMenuErr 

func IsMenuErr(err error) bool

IsMenuErr checks to see if it is a menu err. This is a general check not a specific one.

func IsNoResponseErr 

func IsNoResponseErr(err error) bool

IsNoResponseErr checks to see if err is of type no response returned by menu.

func IsTooManyErr 

func IsTooManyErr(err error) bool

IsTooManyErr checks to see if err is of type too many returned by menu.

Types 

type Menu struct {
	// contains filtered or unexported fields
}

Menu is used to display options to a user. A user can then select options and Menu will validate the response and perform the correct action.

func NewMenu 

func NewMenu(question string) *Menu

NewMenu creates a menu with a wlog.UI as the writer. 

func (m *Menu) Action(function func(Opt) error)

Action adds a default action to use in certain scenarios. If the selected option (by default or user selected) does not have a function applied to it this will be called. If there are no default options and no option was selected this will be called with an option that has an ID of -1. 

func (m *Menu) AddColor(optionColor, questionColor, responseColor, errorColor wlog.Color)

AddColor will change the color of the menu items. optionColor changes the color of the options. questionColor changes the color of the questions. errorColor changes the color of the question. Use wlog.None if you do not want to change the color. 

func (m *Menu) ChangeReaderWriter(reader io.Reader, writer, errorWriter io.Writer)

ChangeReaderWriter changes where the menu listens and writes to. reader is where user input is collected. writer and errorWriter is where the menu should write to. 

func (m *Menu) ClearOnMenuRun()

ClearOnMenuRun will clear the screen when a menu is ran. This is checked when LoopOnInvalid is activated. Meaning if an error occurred then it will clear the screen before asking again. 

func (m *Menu) IsYesNo(def int)

IsYesNo sets the menu to a yes/no state. Does not show options but does ask question. Will also parse the answer to allow for all variants of yes/no (IE Y yes No ...) Specify the default value using def. 0 is for yes and 1 is for no. Both will call the Action function you specified. Opt{ID: 0, Text: "y"} for yes and Opt{ID: 1, Text: "n"} for no will be passed to the function. 

func (m *Menu) LoopOnInvalid()

LoopOnInvalid is used if an invalid option was given then it will prompt the user again. 

func (m *Menu) MultipleAction(function func([]Opt) error)

MultipleAction is called when multiple options are selected (by default or user selected). If this is set then it uses the separator string specified by SetSeparator (Default is a space) to separate the responses. If this is not set then it is implied that the menu only allows for one option to be selected. 

func (m *Menu) Option(title string, isDefault bool, function func() error)

Option adds an option to the menu for the user to select from. title is the string the user will select isDefault is whether this option is a default option (IE when no options are selected). function is what is called when only this option is selected. If function is nil then it will default to the menu's Action. 

func (m *Menu) Run() error

Run is used to execute the menu. It will print to options and question to the screen. It will only clear the screen if ClearOnMenuRun is activated. This will validate all responses. Errors are of type MenuError. 

func (m *Menu) SetDefaultIcon(icon string)

SetDefaultIcon sets the icon used to identify which options will be selected by default 

func (m *Menu) SetSeparator(sep string)

SetSeparator sets the separator to use when multiple options are valid responses. Default value is a space. 

func (m *Menu) SetTries(i int)

SetTries sets the number of tries on the loop before failing out. Default is 3. Negative values act like 0. 

type MenuError struct {
	Err       error
	Res       string
	TriesLeft int
}

MenuError records menu errors 

func (e *MenuError) Error() string

Error prints the error in an easy to read string.

type Opt 

type Opt struct {
	ID   int
	Text string
	// contains filtered or unexported fields
}

Opt is what Menu uses to display options to screen. Also holds information on what should run and if it is a default option

Source Files

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