In {TAIL ~ alternative}, {HEAD ~ such code} can be interpreted by the CUI 18 as a new microinstruction 
In
In { TAIL ~ alternative } , { HEAD ~ such code } can be interpreted by the CUI 18 as a new microinstruction
REL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH