/**
* GMachineDebugger provides debug callback method to GMachineExecutor. GMachineExecutor
* calls this debug callback method every time it executes an instruction. It is GMachineDebugger's
* resposibility to determine whether we need to stop there or continue to execute.
*
* GMachineDebugger controls everything debugging related, like breakpoints, step/trace. It depends on
* these information to control the execution flow.
*
* GMachineDebugger also has methods to view/change variable values and internal status in GMachine.
*/
class GMachineDebugger {


}; // class GMachineDebugger