- | MQSelect of mqrvar * mqlist * mqbool (* rvar, list, boolean *)
- | MQUse of mqlist * mqsvar (* list, Position attribute *)
- | MQUsedBy of mqlist * mqsvar (* list, Position attribute *)
- | MQPattern of mqpattern (* pattern *)
- | MQUnion of mqlist * mqlist (* *)
- | MQIntersect of mqlist * mqlist (* *)
+ | MQSelect of mqrvar * mqlist * mqbool (* rvar, list, boolean *)
+ | MQUse of mqlist * mqsvar (* list, Position attribute *)
+ | MQUsedBy of mqlist * mqsvar (* list, Position attribute *)
+ | MQPattern of mqpattern (* pattern *)
+ | MQUnion of mqlist * mqlist (* *)
+ | MQDiff of mqlist * mqlist (* *)
+ | MQIntersect of mqlist * mqlist (* *)
+ | MQSortedBy of mqlist * mqorder * mqfunc (* *)