gistfile1.swift

class ST_Initial: ST_Root {

    var selection = NodeSelection()
    override var stateName:String {return "Singleselection"}

    init(context: PStateMachineContext) {
        super.init(context)
    }

    override func perform(f: FunctionEnum) {
        switch f {
        case let .mouseDown(event):
            if let node = nodeAtLocation(event) {
                selection.toggleSingle(node)
            }

        case let .keyModFlags(m):
            if (m & NSEventModifierFlags.ShiftKeyMask) == NSEventModifierFlags.ShiftKeyMask {
                //Note: When the selection in this class changes, the selection in the parent state stays unchanged, this is why it is passed as an "inout"
                pushState(ST_MultiSelection(context: context, selection:&selection))
            }

        default:
            return

        }
    }

    private func nodeAtLocation(e:NSEvent) -> HexNode? {
        if let (node,location,offset) = getNodeAtEvent(e) {
            if let node = node {
                return node
            }
        }
        return nil
    }

}

class ST_MultiSelection: ST_Initial {

    override var stateName:String {return "Multiselection"}

    init(context: PStateMachineContext, inout selection:NodeSelection) {
        super.init(context: context)
        self.selection = selection
    }

    override func perform(f: FunctionEnum) {
        switch f {
        case let .mouseDown(event):
            if let node = nodeAtLocation(event) {
                selection.toggleMulti(node)
            }

        case let .keyModFlags(m):
            if !(m & NSEventModifierFlags.ShiftKeyMask == NSEventModifierFlags.ShiftKeyMask) {
                popState()
            }
        default:
            return
        }
    }

}


class NodeSelection {
    var list = [HexNode]()

    func toggleSingle(entry:HexNode) {
        clear()
        if !entry.selected {
            entry.selected = true
            assert(list.count == 0)
            list.append(entry)
        }
    }

    func toggleMulti(entry:HexNode) {
        if entry.selected {
            for (i,n) in enumerate(list) {
                if n === entry {
                    list.removeAtIndex(i)
                    n.selected = false
                    break
                }
            }
        } else {
            entry.selected = true
            list.append(entry)
        }
    }

    func set(entry:HexNode) {
        list.each{$0.selected = false}
        clear()
        list.insert(entry, atIndex: 0)
        entry.selected = true
    }

    func clear() {
        list.each{$0.selected = false}
        list.removeAll(keepCapacity: false)
    }
}