- parenIf pn [p_predBoxed p, space 1, p_record r1, space 1,
- punct "=>", space 1, p_record r2]
+ (case (StringMap.numItems r1, StringMap.numItems r2) of
+ (0, 0) => parenIf pn [p_predBoxed p]
+ | (_, 0) => parenIf pn [p_predBoxed p, space 1, p_record r1]
+ | _ => parenIf pn [p_predBoxed p, space 1, p_record r1, space 1,
+ punct "=>", space 1, p_record r2])