tea

README

Tea

Tea provides an Elm inspired functional framework for interactive command-line programs. Works great for inline and full-screen interactivity.

Examples

See the examples directory.

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Sponsors

This project is sponsored by CTO.ai, making it easy for development teams to create and share workflow automations without leaving the command line.

And my GitHub sponsors:

Documentation

Overview

Package tea provides an Elm inspired functional framework for interactive command-line programs.

Index

• type Cmd
  • func Batch(cmds ...Cmd) Cmd
• type Init
• type Model
• type Msg
  • func Quit(ctx context.Context) Msg
• type Program
  • func NewProgram(init Init, update Update, view View) *Program
  • func (p *Program) Start(ctx context.Context) error
• type Update
• type View

Types

type Cmd

type Cmd func(context.Context) Msg

Cmd is a function used to perform an action, when complete you may return a message, error, or nil.

For example a comand which removes a user from a database might return a struct UserRemoved with its ID so that Update() can remove it before rendering.

Errors are special cased, so you may return an error in place of a message, this will cause the program to exit and the error will be printed. If you wish to handle errors in a different way, you should return a message containing the error and update your model accordingly.

Returning nil is a no-op.

func Batch

func Batch(cmds ...Cmd) Cmd

Batch performs many commands concurrently, with no order guarantees.

type Init

type Init func(context.Context) (Model, Cmd)

Init is a function which is invoked when starting your program, returning the initial model and optional command.

type Model

type Model interface{}

Model is the model which defines all or a subset of your program state.

type Msg

type Msg interface{}

Msg is passed to your program's Update() function, representing an action which was performed, for example a ItemRemoved msg might be a struct containing the ID of the item removed.

func Quit

func Quit(ctx context.Context) Msg

Quit is a message which exits the program.

For example:

return m, tea.Quit

type Program

type Program struct {
	// Init function.
	Init

	// Update function.
	Update

	// View function.
	View
	// contains filtered or unexported fields
}

Program is a terminal application comprised init, update, and view functions.

func NewProgram

func NewProgram(init Init, update Update, view View) *Program

NewProgram returns a new program.

func (*Program) Start

func (p *Program) Start(ctx context.Context) error

Start the program.

type Update

type Update func(context.Context, Msg, Model) (Model, Cmd)

Update is a function which is invoked for every message, allowing you to return a new, updated model and optional command.

type View

type View func(context.Context, Model) string

View is a function used to render the program's model before it is written to the terminal.