native channel ScreenUpdate {
	in screen(curSc: Json, update(curSc, nextSc)) = nextSc
}

native channel SetVisible(wid: Str) {
	in screen.widgets.{wid}.visible(curVisible: Bool, setVisible(nextVisible)) = nextVisible
}

native channel SetText(wid: Str) {
	in screen.widgets.{wid}.text(curText: Str, setText(nextText)) = nextText
}

native channel MouseEvent(wid: Str) {
	out screen.widgets.{wid}.state(curState: Int, mouseEvent(nextState)) = nextState
}

native channel TextEvent(wid: Str) {
	out screen.widgets.{wid}.text(curText: Str, textEvent(nextText)) = nextText
}

channel AddButton {
	out screen.widgets(widgets: Map, addButton(wid: Str, text: Str)) = insert(widgets, wid, {"type": "button", "text": text, "state": 0})
}

channel AddLabel {
	out screen.widgets(widgets: Map, addLabel(wid: Str, text: Str)) = insert(widgets, wid, {"type": "label", "text": text, "state": 0})
}

channel AddInputText {
	out screen.widgets(widgets: Map, addInputText(wid: Str)) = insert(widgets, wid, {"type": "inputText", "state": 0})
}

channel Init {
	out screen.widgets(widgets: Map, init(_tmp)) = insert(insert(widgets, "0", {"type": "button", "text": "OK", "state": 0}), "1", {"type": "button", "text": "hi", "state": 0})
}