kui-lua

Lua scripts as kui extensions: a script returns its view as a table tree and gets events back as tables.

kui-lua loads a Lua script as an extension a kui host can place in its frame. The script defines view(env, slot), which returns a plain table built with the injected row / column / text / button prelude, and optionally on_event(ev), which hears the events the script's own nodes emit and may return replies for the host. Only data crosses the boundary: no closure lives on either side. Use it when a Rust app on kui wants scriptable panels or plugins.

Install

cargo add kui-lua kui-native

Example

The Rust host reserves a position for the script under a namespace and hears its replies:

use kui_lua::LuaExtension;
use kui_native::{App, NodeSpec, Ui, UiEvent, Value};

struct Host { toggles: u32 }

impl App for Host {
    fn view(&mut self, ui: &mut Ui<'_>) {
        ui.configure_root(NodeSpec::row().fill().pad(16.0).gap(16.0));
        ui.slot_with(
            "todos/panel",
            &Value::map([
                ("title", "todos".into()),
                ("on_toggle", Value::map([("kind", "toggled".into())])),
            ]),
        );
    }

    fn on_event(&mut self, ev: UiEvent) {
        if ev.kind() == Some("toggled") {
            self.toggles += 1;
        }
    }
}

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let script = LuaExtension::from_file("panel.lua")?;
    kui_native::app("todos").extension_as("todos", script).run(Host { toggles: 0 })
}

panel.lua fills the panel slot, reads the host's params and replies with the host's template:

slots = { "panel" }

local done = {}
local on_toggle

function view(env, slot)
  local t = env.theme
  on_toggle = slot.params.on_toggle
  return column {
    width = 300, pad = 16, gap = 10, bg = t.surface, radius = 10,
    text(slot.params.title, { size = 12, color = t.muted }),
    row { on_click = { kind = "toggle", index = 1 },
          text((done[1] and "[x] " or "[ ] ") .. "wire up wgpu") },
  }
end

function on_event(ev)
  if ev.kind == "toggle" then
    done[ev.index] = not done[ev.index]
    local reply = { index = ev.index }
    for k, v in pairs(on_toggle) do reply[k] = v end
    return reply
  end
end

The crate docs list everything a script gets: the builders, the env facts and functions, the slot argument, the props shapes, and kui_lua::luals_meta() for editor completion.

Where it fits

Documentation

• API: https://docs.rs/kui-lua
• Book: https://kui-book.qxuken.dev
• Repository: https://github.com/qxuken/kui

License

MIT