Personally I'm a fan of passing an argument, as long as it doesn't introduce problems with variable arguments or such. It makes sense that way, since relative is kind of an 'argument' to the DND action, and not intended as a global variable. It saves the trouble of keeping it global. And, the conversion process is intended to mostly reflect the DND look, so introducing brackets muddies it up, since that's really only supposed to be introduced by the Begin and End (resp. up and down triangle) actions.