Flutter/Dart神奇的語法

習慣傳統程式語言，這種的初看像謎之符號，細看覺得神奇!!

Future <bool> ShowYesNoDialog(

BuildContext context,

doYes,

doNo

) async

{

return showDialog(

context: context,

builder: (context) => AlertDialog(

actions: <Widget>[

RaisedButton(

onPressed: ((){doYes();}),

),

RaisedButton(

onPressed: ((){doNo();}),

),

],

),

) ??

false;

}

await ShowYesNoDialog(

context, 'SayYesNo', 'Yes or No?',

((){print('yes');}),

((){print('no')}),

);