anchor.diff:          // constructed as [handler stream command] or [handler stream [command]]
           | Handler of Stream * Command list * Guid * Origin option
           // constructed as [equality Density stream] or [equality Density ././Player stream]
  -        // does not allow for relations to parents or siblings, or a wildcard in the relation
  +        // does not allow for relations to parents or siblings, or for a wildcard in the relation
           | Equality of string * obj Relation * Stream * Guid * Origin option
  -        // constructed as [equalities Density ././@ BoxDispatcher/Vanilla None stream]
  +        // constructed as [equalities Density ././@ BoxDispatcher/Vanilla stream]
           // does not allow for relations to parents or siblings
           | Equalities of string * obj Relation * Classification * Stream * Guid * Origin option
   
  
positive.code:           CommandArgs : Expr list }
  
      and [<NoComparison>] Stream =
          // constructed as [event X/Y/Z]
          // does not allow for entity, group, screen, or game events
          | Event of obj Address
          // constructed as [property P ./.]
          // does not allow for properties of parents or siblings, or a wildcard in the relation
          | Property of obj Relation * string
          // constructed as [properties P ./@ EntityDispatcher/Vanilla]
          // does not allow for properties of parents or siblings
          | Properties of obj Relation * Classification * string
          // constructed as [variable v]. Variables can only access lexically prior variables.
          | Variable of Name
          // constructed as [product stream stream]
          | Product of Stream * Stream
          | Sum of Stream * Stream 
  
negative.code:         | Try of Expr * (string list * Expr) list * Origin option
          | Break of Expr * Origin option
          // constructed as [get Density] or [get Density ././Player]
          // does not allow for relations to parents or siblings, or for a wildcard in the relation
          | Get of string * obj Relation * Origin option
  
          (* Special Declarations - only work at the top level, and always return unit. *)
  