dos

Not production ready.

Make portable MS-DOS style graphics with this library which draws inspiration from the React and Flutter projects. Compose interfaces with Widgets. A Widget is the interface that all UI components implement, which provides five essential functions:

1. HandleMouse (process click events)
2. HandleKey (process key events)
3. SetFocused (alert the widget that it has become focused)
4. DisplaySize (produce the predicted size of the widget)
5. Draw (render the component using tcell)

Each widget is controlled by its parent, but it does not know its parent. This means widgets are reusable and rather predictable. Let's look at an example where we have a Center widget with a label child to see this in effect.

widget := &dos.Center{
    Child: &dos.Label{
        Text:  "Hello, world!",
        Style: tcell.StyleDefault.Foreground(tcell.ColorRed),
    },
}

We compose a simple user interface where the label text "Hello, world!" will be centered in the window by the Center widget. Each widget has its own properties, but many have sane defaults. For example, I have omitted the Align property for the Label, so the default value is AlignLeft. Finally, we always take the reference of components, so they may become shallow and used as the Widget type.

This is what the Center struct looks like:

type Center struct {
	Child Widget
}

Widget is that interface mentioned earlier. This is what the example looks like running on my terminal:

You can read the source code for the Center widget. It's a rather simple container, as it just passes on events and does very little to draw. A more complex container might be the Align or Column. The Label widget is also fairly complex, as it ensures compatibility with tricky double-wide characters while allowing for cool features like alignment and box-bounding.

But these are all real widgets that you could make with or without the dos library. There's not a lot of boilerplate, and there's not much going on under the hood. I just think I've done a good job providing your next project a good architectural base, and a good selection of MS-DOS inspired widgets.

FAQ

What does 'dos' do?

dos is a library for Go that makes it simple and easy to build complex graphical applications that run on terminals.

Why do you depend on tcell so heavily?

^ in regards to tcell types being used directly in widgets and the core library.

I understand that it may be appealing to be able to swap backends, but tcell is a very solid library that is on its second revision. It would be a lot of extra work and bloat to make dos agnostic of the backend. This way uses very little code and allows the user to remain closer to the inner workings done by the library (accessing tcell directly).

Is the simplicity of this library part of the solution or the problem?

The simplicity of this library helps you make good programs. You can read less documentation, and get a good understanding of what happens behind the scenes, when you use the library. I'd say that's good design.

Contributing

I want comments and suggestions! Send me a message on Matrix @fivemoreminix:matrix.org

And as always, feel free to make a pull request.

TODO

[X] buffer: Count needs to use inclusive bounds [X] buffer: Cursor concrete type can have an assigned buffer and know how to navigate it. Buffers can have cursors added to their management and be treated as anchors. Users can move cursors and retain ownership of them. [ ] buffer: Cursor Up(times int), Down(times int) etc. repetition [ ] buffer: ManagedBuffer struct is a wrapper over cursors and buffers with a Command-based API with undo and redo. Aims to simplify common text-editing tasks. [X] buffer: Buffer LineDelimiter string and LineHasDelimiter(line) bool [ ] buffer: Make it possible for users of library to change how cursor skips words [ ] buffer: update rope_test.go and harden (abstract into buffer_test.go which tests all types of buffers using same code) [ ] dos: theme.go file with Theme management code and a default theme set. Used by all dos widgets when their style properties are nil. (Requires taking pointer to Styles now) Theme is probably map[string]tcell.Style for example Theme["WidgetState"] or Theme["ButtonFocused"]