(cConsOps: CConsOps[Input, HeadData, HeadDelta, TailData, TailDelta]).choice(caseHead)(caseTail)(headToLayer, tailToLayer, lub, commonToLayer)
(cConsOps: CConsOps[Input, HeadData, HeadDelta, TailData, TailDelta]).head
(cConsOps: CConsOps[Input, HeadData, HeadDelta, TailData, TailDelta]).isInl
(cConsOps: CConsOps[Input, HeadData, HeadDelta, TailData, TailDelta]).tail