kkallio@8: datatype panelState = Open | Closed
kkallio@8: 
kkallio@8: type formatCtl = {FormatPanel : xbody -> xbody -> xbody,
kkallio@8:                   OpenCtl : transaction unit -> xbody,
kkallio@8:                   CloseCtl : transaction unit -> xbody}
kkallio@8: 
kkallio@8: val defaultFormat = {FormatPanel = fn ctl panel => <xml>{ctl}{panel}</xml>,
kkallio@8:                      OpenCtl = fn behaviour => <xml><button value="Open" onclick={behaviour}/></xml>,
kkallio@8:                      CloseCtl = fn behaviour => <xml><button value="Close" onclick={behaviour}/></xml>}
kkallio@8:                     
kkallio@8: con togglePanel t = {PanelState : source panelState,
kkallio@8:                      FormatCtl : formatCtl,
kkallio@8:                      Content : t}
kkallio@8: 
kkallio@8: open Gui
kkallio@8: 
kkallio@8: fun create [t ::: Type] (toXml : gui t) (f : formatCtl) (content : t) (startOpen : bool) : transaction (togglePanel t) =
kkallio@8:     state <- source (if startOpen then Open else Closed);
kkallio@8: 
kkallio@8:     return {PanelState = state,
kkallio@8:             FormatCtl = f,
kkallio@8:             Content = content}
kkallio@8: 
kkallio@8: fun render [t ::: Type] (_ : gui t) (panel : togglePanel t) =
kkallio@8:     let
kkallio@8:         val openCtl = panel.FormatCtl.CloseCtl (set panel.PanelState Closed)
kkallio@8:         val closeCtl = panel.FormatCtl.OpenCtl (set panel.PanelState Open)
kkallio@8: 
kkallio@8:         val content = toXml panel.Content
kkallio@8:     in
kkallio@8:         panel.FormatCtl.FormatPanel
kkallio@8:             <xml>
kkallio@8:               <dyn signal={c <- signal panel.PanelState;
kkallio@8:                            return
kkallio@8:                                (case c of
kkallio@8:                                     Open => <xml>{openCtl}</xml>
kkallio@8:                                   | Closed => <xml>{closeCtl}</xml>)
kkallio@8:                           }/>
kkallio@8:             </xml>
kkallio@8: 
kkallio@8:             <xml>
kkallio@8:               <dyn signal={c <- signal panel.PanelState;
kkallio@8:                            return
kkallio@8:                                (case c of
kkallio@8:                                     Open => <xml>{content}</xml>
kkallio@8:                                   | Closed => <xml/>)
kkallio@8:                           }/>
kkallio@8:             </xml>
kkallio@8:     end
kkallio@8: 
kkallio@8: fun gui_togglePanel [t ::: Type] (_ : gui t) = mkGui render