1	import Base
2	import ./world.bend as W
3	import ./execution_composer_layout.bend as Layout
4	import ./execution_relation_operation.bend as O
5	
6	# The closed command declaration binds route and enqueue to the existing Buffer.
7	# These adapters do not allocate a queue or accept a World callback.
8	type Commands<-Q:Type,-S:Data> is Type:
9	  Commands{relate:Q -> W.Handle<S> -> W.Handle<S> -> Q,unrelate:Q -> W.Handle<S> -> Q}
10	type HierarchyCommands<-Q:Type,-S:Data> is Type:
11	  HierarchyCommands{relations:Commands<Q,S>,reorder:Q -> W.Handle<S> -> List<&2,W.Handle<S>> -> Q}
12	def commands(~S:Data,~Q:Type,~route:Layout.Route,~enqueue:Q -> Layout.Route -> O.Operation<S> -> Q) -> Commands<Q,S>:
13	  Commands{queue => source => target => enqueue(queue,route,O.Relate{source,target}),queue => source => enqueue(queue,route,O.Unrelate{source})}
14	def hierarchy(~S:Data,~Q:Type,~route:Layout.Route,~enqueue:Q -> Layout.Route -> O.Operation<S> -> Q) -> HierarchyCommands<Q,S>:
15	  HierarchyCommands{commands(~S,~Q,~route,~enqueue),queue => parent => children => enqueue(queue,route,O.Reorder{parent,children})}
16	def relate_field(~S:Data,~Q:Type,cap:Commands<Q,S>) -> Q -> W.Handle<S> -> W.Handle<S> -> Q:
17	  match cap:
18	    case Commands{relate,_}:relate
19	def unrelate_field(~S:Data,~Q:Type,cap:Commands<Q,S>) -> Q -> W.Handle<S> -> Q:
20	  match cap:
21	    case Commands{_,unrelate}:unrelate
22	def relations_field(~S:Data,~Q:Type,cap:HierarchyCommands<Q,S>) -> Commands<Q,S>:
23	  match cap:
24	    case HierarchyCommands{relations,_}:relations
25	def reorder_field(~S:Data,~Q:Type,cap:HierarchyCommands<Q,S>) -> Q -> W.Handle<S> -> List<&2,W.Handle<S>> -> Q:
26	  match cap:
27	    case HierarchyCommands{_,reorder}:reorder