Depends on which version you are using. In AX 2009 and AX 2012 you can use methods existing in SysQueryRangeUtil class, ofcourse you can add your own. Methods can have arguments or not.
In AX 2012 see ProjTable_MyProjects Query in AOT as an example:
Check the WorkerResposible Range
Queries\ProjTable_MyProjects\Composite Query\ProjTable_NoFilter\Data Sources\ProjTable(ProjTable)\Ranges\WorkerResponsible
there is a following range value
((WorkerResponsible==currentWorkerRecId()) && ...
currentWorkerRecId() is the static method in SysQueryRangeUtil class:
public static HcmWorkerRecId currentWorkerRecId()
{
return HcmWorker::userId2Worker(curUserId());
}
Regards,
Sebastian