What's this?

minilight is a SDL2-based graphics library, equipped with component system.
Lua is a lightweight interpreted language.

With this library, you can write a minilight component in Lua language.

Getting Started

See example directory. Main.hs is an entrypoint for minilight engine.

mainFile = "example/main.lua"
main :: IO ()
main = runLightT $ runMiniloop
  (defConfig { hotConfigReplacement = Just "example", appConfigFile = Just "" })
  initial
  (const mainloop)
 where
  initial = do
    comp <- registerComponent mainFile newLuaComponent
    reload mainFile
    return ()
  mainloop :: MiniLoop ()
  mainloop = do
    ref <- view _events
    evs <- liftIO $ tryReadMVar ref
    let notifys = case evs of
          Just evs -> mapMaybe asNotifyEvent evs
          _        -> []
    unless (null notifys) $ reload mainFile

Some notes here:

When you pass hotConfigReplacement field, minilight will watch the given directory and emits file changed/created/delete events during the mainloop.
For registerComponent you need to pass the filename like example/main.lua. The path is relative where you run cabal run.
In mainloop, watches any events and reload the component. The reload function will load the lua file again and swap the component dynamically (code swapping).

local minilight = require("minilight")
function onDraw()
    print("[LUA OUTPUT] hello")
    return {
        minilight.translate(50, 50, minilight.picture("example/example.png")),
        minilight.translate(100, 100, minilight.text("こんにちは世界",
                                                     {0, 0, 0, 0})),
        minilight.translate(30, 50,
                            minilight.text("Hello, World!", {255, 0, 0, 0}))
    }
end
_G.onDraw = onDraw

For lua part:

Require minilight library. This will be implicitly loaded by minilight-lua.
You need to export onDraw : () -> Array<minilight.Figure> function globally. This function will be called from Haskell and the returned array will be rendered in the component.