start_app`(path, environment)`

Starts the app located at path, with environment as env.

Returns the PID of the new app or nil.

local app = start_app("apps/myapp.nib", {
    super = "cool"
})

if app then
    -- Yes!!
end

The environment variables x, y, width and height control the area of the screen which the new app will be allowed to draw.

WARNING: if the app draws using direct memory writes this is not enough to constrain it to a specific area of the screen.

start_app("apps/constrained.nib", {
    x = 10, y = 10,
    width = 100, height = 100,
})

stop_app`(pid)`

Stops a given app. If pid is 0, stop itself.

stop_app(0)

WARNING: you cannot pause apps which you did not start

Pause the given app.

WARNING: you cannot resume apps which you did not start

Resume the given app.

The message (an arbitrary value) will be sent to the app of PID = pid.

It can use receive_message() to receive it

Returns the next message or nil.