1	import Base
2	import ./lifecycle.bend as Life
3	
4	type Lookup<-V:Data> is Data:
5	  Viewed{view:V,stamp:Life.Stamp}
6	  LookupRefused{}
7	type Edit<-P:Type,-Out:Type> is Type:
8	  Edited{output:Out}
9	  Unchanged{unused:P -> P & Out}