1	import Base
2	import ./execution_composer_layout.bend as Layout
3	import ./execution_resource_policy.bend as Policy
4	import ./execution_relation_resource_publication.bend as Cast
5	import ./execution_relation_store.bend as Store
6	import ./relation_types.bend as T
7	
8	type GraphView<-S:Data> is Data:
9	  GraphView{route:Layout.Route,descriptor:T.Descriptor<S>,namespace:U32,graph:T.Graph<S>}
10	def Program(~S:Data,~resources:Layout.Layout) -> Type:
11	  Layout.resources(~S,resources) -> Layout.resources(~S,resources) & List<&2,GraphView<S>>
12	def empty(~S:Data,~resources:Layout.Layout,owners:Layout.resources(~S,resources)) -> Layout.resources(~S,resources) & List<&2,GraphView<S>>:
13	  (owners,[])
14	def observed(~S:Data,~descriptor:T.Descriptor<S>,~key:String,~origin:Layout.Layout,route:Layout.Route,slot:Layout.ResourceSlot<S,Layout.Viewed<Store.Store<S,descriptor>,Store.View<S,descriptor>>,key,origin>) -> Layout.ResourceSlot<S,Layout.Viewed<Store.Store<S,descriptor>,Store.View<S,descriptor>>,key,origin> & GraphView<S>:
15	  match slot:
16	    case Layout.ResourceSlot{Layout.Viewed{Store.Store{+namespace,+graph,failures,sequence,nextReader},cache},stamp}:(Layout.ResourceSlot{Layout.Viewed{Store.Store{namespace,graph,failures,sequence,nextReader},cache},stamp},GraphView{route,descriptor,namespace,graph})
17	def restored(~S:Data,~resources:Layout.Layout,~route:Layout.Route,~descriptor:T.Descriptor<S>,~payload:{Layout.payload(resources,route) == Store.Store<S,descriptor> : Type},~view:{Layout.view(resources,route) == Store.View<S,descriptor> : Data},previous:List<&2,GraphView<S>>,rest:Layout.resource_rest(~S,resources,route),result:Layout.ResourceSlot<S,Layout.Viewed<Store.Store<S,descriptor>,Store.View<S,descriptor>>,Layout.key(resources,route),Layout.origin(resources,route)> & GraphView<S>) -> Layout.resources(~S,resources) & List<&2,GraphView<S>>:
18	  match result:
19	    case (slot,seen):(Layout.resource_put(~S,resources,route,rest,Cast.slot(~S,~Layout.key(resources,route),~Layout.origin(resources,route),~Store.Store<S,descriptor>,~Layout.payload(resources,route),~Store.View<S,descriptor>,~Layout.view(resources,route),Equal.sym(Type,Layout.payload(resources,route),Store.Store<S,descriptor>,payload),Equal.sym(Data,Layout.view(resources,route),Store.View<S,descriptor>,view),slot)),seen <> previous)
20	def selected(~S:Data,~resources:Layout.Layout,~route:Layout.Route,~descriptor:T.Descriptor<S>,~payload:{Layout.payload(resources,route) == Store.Store<S,descriptor> : Type},~view:{Layout.view(resources,route) == Store.View<S,descriptor> : Data},previous:List<&2,GraphView<S>>,result:Layout.resource_rest(~S,resources,route) & Layout.ResourceSlot<S,Layout.stored(resources,route),Layout.key(resources,route),Layout.origin(resources,route)>) -> Layout.resources(~S,resources) & List<&2,GraphView<S>>:
21	  match result:
22	    case (rest,slot):restored(~S,~resources,~route,~descriptor,~payload,~view,previous,rest,observed(~S,~descriptor,~Layout.key(resources,route),~Layout.origin(resources,route),route,Cast.slot(~S,~Layout.key(resources,route),~Layout.origin(resources,route),~Layout.payload(resources,route),~Store.Store<S,descriptor>,~Layout.view(resources,route),~Store.View<S,descriptor>,payload,view,slot)))
23	def gathered(~S:Data,~resources:Layout.Layout,~route:Layout.Route,~descriptor:T.Descriptor<S>,~payload:{Layout.payload(resources,route) == Store.Store<S,descriptor> : Type},~view:{Layout.view(resources,route) == Store.View<S,descriptor> : Data},result:Layout.resources(~S,resources) & List<&2,GraphView<S>>) -> Layout.resources(~S,resources) & List<&2,GraphView<S>>:
24	  match result:
25	    case (owners,previous):selected(~S,~resources,~route,~descriptor,~payload,~view,previous,Layout.resource_take(~S,resources,route,owners))
26	# A closed grant extends this observer beside its mutating dispatcher. It never
27	# grants gameplay access to the graph owner, failure channel or resource lens.
28	def extend(~S:Data,~resources:Layout.Layout,~route:Layout.Route,~descriptor:T.Descriptor<S>,~payload:{Layout.payload(resources,route) == Store.Store<S,descriptor> : Type},~view:{Layout.view(resources,route) == Store.View<S,descriptor> : Data},~protected:{Layout.policy(resources,route) == Policy.ProtectedRelation{S,descriptor} : Policy.Policy},previous:Program(~S,~resources)) -> Program(~S,~resources):
29	  owners => gathered(~S,~resources,~route,~descriptor,~payload,~view,previous(owners))