init {
	screen := {
					"widgets": {
										"001": {"type": "button", "text": "a", "state": 0}, 
										"002": {"type": "textInput", "text": "", "state": 0}
									}, 
					"layout": true
				}
}

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

native channel SetLayout {
	in screen.layout(curLayout: Bool, setLayout(nextLayout)) = nextLayout
}

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 AddTextInput {
	out screen.widgets(widgets: Map, addTextInput(wid: Str)) = insert(widgets, wid, {"type": "textInput", "text": "", "state": 0})
}


channel signUp{
	out datastore.accounts(accounts: Map, signUp(id, name)) = insert(accounts, id, name)
}

channel createBook {
	out datastore.books(books: Map, createBook(id, title, aid)) = insert(books, id, {"title": title, "aid": aid})
}