brick is a Haskell terminal user interface programming library in the
style of gloss. This means
you write a function that describes how your user interface should look,
but the library takes care of a lot of the book-keeping that so commonly
goes into writing such programs.
brick exposes a declarative API. Unlike most GUI toolkits which
require you to write a long and tedious sequence of "create a widget,
now bind an event handler",
brick just requires you to describe your
interface using a set of declarative combinators. Then you provide a
function to transform your application state when input or other kinds
of events arrive.
Under the hood, this library builds upon vty, so some knowledge of Vty will be helpful in using this library.
This library deprecates vty-ui.
Here's an example interface (see
withBorderStyle unicode $ borderWithLabel (str "Hello!") $ (center (str "Left") <+> vBorder <+> center (str "Right"))
┌─────────Hello!─────────┐ │ │ │ │ │ │ │ Left │ Right │ │ │ │ │ │ │ └────────────────────────┘
To get an idea of what some people have done with
brick, take a look
at these projects:
gotta-go-fast, a typing tutor: https://github.com/hot-leaf-juice/gotta-go-fast
matterhorn, a client for Mattermost: https://github.com/matterhorn-chat/matterhorn
viewprof, a GHC profile viewer: https://github.com/maoe/viewprof
tart, a mouse-driven ASCII art drawing program: https://github.com/jtdaugherty/tart
silly-joy, an interpreter for Joy in Haskell: https://github.com/rootmos/silly-joy
herms, a command-line tool for managing kitchen recipes: https://github.com/jackkiefer/herms
purebred, a mail user agent: https://github.com/purebred-mua/purebred
$ cabal sandbox init $ cabal install -j -f demos $ .cabal-sandbox/bin/brick-???-demo
To get started, see the user guide.
brick comes in a variety of forms:
brick comes with a bunch of widget types to get you started:
- Vertical and horizontal box layout widgets
- Basic single- and multi-line text editor widgets
- List widget
- Progress bar widget
- Simple dialog box widget
- Border-drawing widgets (put borders around or in between things)
- Generic scrollable viewports
- Extensible widget-building API
- (And many more general-purpose layout control combinators)
In addition, some of
brick's more powerful features may not be obvious
- All widgets can be arranged in predictable layouts so you don't have to worry about terminal resizes.
- Attribute management is flexible and can be customized at runtime on a per-widget basis.
brick-users Google Group / e-mail list is a place to discuss
library changes, give feedback, and ask questions. You can subscribe at:
There are some places were I have deliberately chosen to worry about
performance later for the sake of spending more time on the design (and
to wait on performance issues to arise first).
brick is also something
of an experimental project of mine and some aspects of the design
involve trade-offs that may are not entirely settled. In addition you
can expect this library to follow a principle of fearless improvement:
new versions will make (sometimes substantial) API changes if those
changes really do make the library better. I will place more importance
on getting the API right than on maintaining backwards compatibility.
brick exports an extension API that makes it possible to make your own
packages and widgets. If you use that, you'll also be helping to test
whether the exported interface is usable and complete!
Please file bug reports as GitHub issues. For best results:
Include the versions of relevant software packages: your terminal emulator,
vtywill be the most important ones.
Clearly describe the behavior you expected ...
... and include a minimal demonstration program that exhibits the behavior you actually observed.
If you decide to contribute, that's great! Here are some guidelines you should consider to make submitting patches easier for all concerned:
- If you want to take on big things, talk to me first; let's have a design/vision discussion before you start coding. Create a GitHub issue and we can use that as the place to hash things out.
- Please make changes consistent with the conventions I've used in the codebase.
- Please adjust or provide Haddock and/or user guide documentation relevant to any changes you make.