Build terminal user interfaces and games using The Elm Architecture (Model/View/Update)
Track state in your model, listen for user input to update that state, and render your UI as a string representation of the current state. gren-tui will handle re-drawing only the lines you've output when your model changes.
Uses the purely functional, very pleasant gren programming language.
module Main exposing (main)
import Init
import Node
import Task
import Time
import Tui
main : Tui.Program Model Msg
main =
Tui.defineProgram
{ init = init
, update = update
, view = view
, subscriptions = subscriptions
, onInput = GotInput
}
type alias Model =
{ ticks : Int }
init : Node.Environment -> Init.Task { model : Model, command : Cmd Msg }
init env =
Node.startProgram
{ model = { ticks = 0 }
, command = Cmd.none
}
type Msg
= Tick Time.Posix
| GotInput Tui.Input
update : Msg -> Model -> { model : Model, command : Cmd Msg }
update msg model =
case msg of
Tick _ ->
{ model = { model | ticks = model.ticks + 1 }
, command = Cmd.none
}
GotInput input ->
{ model = model
, command =
case input of
Tui.KeyChar "q" -> Task.execute Node.exit
_ -> Cmd.none
}
view : Model -> String
view model =
String.join ""
[ "How high can I count? Let's see: "
, String.fromInt model.ticks
, "\nPress q to quit."
]
subscriptions : Model -> Sub Msg
subscriptions model =
Time.every 1000 TickIf you haven't already, install gren and take a look at the book if you want to get up to speed with the language.
Then create a gren node application:
mkdir myapp
cd myapp
gren init --platform=node
Install the gren-tui package:
gren package install blaix/gren-tui
(see next section for other packages you may want to install)
Then create a src/Main.gren file. For a starting point, see:
Then compile and run with:
gren make src/Main.gren
node app
These packages are useful in a gren-tui application:
- gren-ansi for controlling the cursor and text-styling
- gren-array2d to manipulate your view as a 2-D grid.
See the game example for an app that uses both of these.
If you have questions, suggestions, find a bug, or want to follow updates to the package, you can:
- Follow me on mastodon at @[email protected].
- Join the
#gren-tuichannel on the gren discord. - File an issue on github.