Protection call in dart

README.md

Call function in protection mode, it's more comfortable way to handle errors.
How to use:

void _handleMessage(WebSocket wsock, String data){
    var parts = pcall(() => _parseMessage(data), (error, st){
      _messageFormatNotAcceptedHandler(wsock, error, st);
    });
    if (isFail(parts)) return;
    var command = parts[0];
    Map playload = pcall(() => JSON.decode(parts[1]), (error, st){
      _messageFormatNotAcceptedHandler(wsock, error, st);
    });
    callCommand(wsock, command, playload);
  }

pcallAsync just a function call pcall and return the result with typing mark Future for type checking.

pcall.dart

typedef void CodeProtectionHandler(dynamic error, StackTrace trace);

enum _PcallFailMark {
  Fail
}

dynamic pcall(dynamic target, CodeProtectionHandler cph){
  if (target is Function){
    try {
      return target();
    } catch (e,st){
      cph(e,st);
      return _PcallFailMark.Fail;
    }
  } else if(target is Future) {
    return target.catchError((e,[st]){
      cph(e,st);
      return _PcallFailMark.Fail;
    });
  }
  return null;
}

FutureOr<_PcallFailMark> pcallAsync<R>(Future target, CodeProtectionHandler cph){
  return pcall(target, cph);
}

bool isFail(dynamic pcallResult){
  if (pcallResult is _PcallFailMark && pcallResult == _PcallFailMark.Fail) return false;
  return true;
}