var CEF = {
   Callbacks:{/*guid*/}
};

procedure resolveWebGadgetEx(GUID.s, P.s)   
   ExecuteWebGadgetExJavaScript(PBWebGadgetEx, "CEF.Resolves['" + GUID + "'](" + P + ")", @OutputWebGadgetEx, @ErrorOutputWebGadgetEx)   
endProcedure

CEF.call = (fun, arg={}) => {   // async call -> return value via resolve used
   let R = new Promise((resolve, reject) => {
      arg.GUID = JS.guid()
      
      CEF.Resolves[arg.GUID]   = resolve
      
      PB.call.call(null, fun, JSON.stringify(arg))
   });
   
   return R
};

CEF.callS = (fun, arg) => {      // sync call -> no return value used
   PB.call.call(null, fun, JSON.stringify(arg))
};

structure ArgWebGadgetEx
   GUID   .s
endStructure

structure saveExcelWorkbookArgWG extends ArgWebGadgetEx   
   WB             .i
   FilePath   .s
endStructure

procedure saveExcelWorkbookWG(*P)
   var P.s   = PeekS(*P)
   var J = ParseJSON(#PB_Any, P)
   var Arg.saveExcelWorkbookArgWG
   
   ExtractJSONStructure(JSONValue(J), @Arg, saveExcelWorkbookArgWG)
      
   var R = bool(saveExcelWorkbook(Arg\WB, Arg\FilePath) = 0)
      
   resolveWebGadgetEx(Arg\GUID, Str(R))
endProcedure

async free(){
      CEF.callS('freeExcelWorkbook', {WB:this.Nr})  // no return value needed...
   }
   
   async save(FilePath){
      return await CEF.call('saveExcelWorkbook', {WB:this.Nr, FilePath})
   }