import AppKit

let app = NSApplication.shared
app.setActivationPolicy(.regular)

let window = NSWindow(
    contentRect: NSMakeRect(0, 0, 640, 480),
    styleMask: [.titled, .closable],
    backing: .buffered,
    defer: true
)
window.title = "Hello, world!"
window.makeKeyAndOrderFront(nil)

app.activate(ignoringOtherApps: true)
app.run()