[SoftwareBug2.0]

Consider this:

class Posedge_toggle{
	bool value,last;

	public:
	Posedge_toggle():value(0),last(1){}

	void update(bool sample){
		if(sample&&!last) value=!value;
		last=sample;
	}

	bool get()const{ return value; }
};
//...

Posedge_toggle t;
while (IsOperatorControl())
{
    t.update(secondaryController->GetRawButton(6));
    if(t.get()){
        //do tank drive
    }else{
       //do arcade drive
    }
    wait(0.02);
}

It decouples the logic of how to make things toggle from the logic to read joysticks, etc.