1	import Base
2	import ./world.bend as W
3	import ./event_runtime.bend as Ev
4	import ./event_stream.bend as Leaf
5	import ./event_family_routing.bend as Route
6	import ./ordinary_event_declaration.bend as Event
7	import ./capabilities.bend as Cap
8	
9	# Read-only retained leaf values. No operational reader action or World adapter.
10	def selected(~S:Data,~E:Data,allowed:Bool,+stream:Leaf.Stream<S,E>) -> Leaf.Stream<S,E> & Maybe<&2,List<&2,E>>:
11	  match allowed stream:
12	    case False{} stream:(stream,None{})
13	    case True{} Leaf.Stream{domain,+batches,positions,nextReader,frameStart,boundary,capacity,dropped}:(Leaf.Stream{domain,batches,positions,nextReader,frameStart,boundary,capacity,dropped},Some{Ev.values(~E,batches)})
14	def declared(~S:Data,~E:Data,declaration:Event.Declaration<S,E>,+stream:Leaf.Stream<S,E>) -> Leaf.Stream<S,E> & Maybe<&2,List<&2,E>>:
15	  match declaration stream:
16	    case Event.Declaration{_,Event.Write{}} stream:(stream,None{})
17	    case Event.Declaration{Event.Domain{expected},Event.Read{}} Leaf.Stream{Event.Domain{+actual},+batches,+positions,+nextReader,+frameStart,+boundary,+capacity,+dropped}:selected(~S,~E,String.eq(expected,actual),Leaf.Stream{Event.Domain{actual},batches,positions,nextReader,frameStart,boundary,capacity,dropped})
18	def restored(~S:Data,~C:Type,~R:Type,~P:Data,~E:Data,~F:Type,~take:F -> F & Leaf.Stream<S,E>,~put:F -> Leaf.Stream<S,E> -> F,world:W.World<S,C,R,P>,tick:Nat,family:F,returned:Leaf.Stream<S,E> & Maybe<&2,List<&2,E>>) -> Route.Runtime<S,C,R,P,F> & Maybe<&2,List<&2,E>>:
19	  match returned:
20	    case (stream,values):(Route.Runtime{world,put(family,stream),tick},values)
21	def taken(~S:Data,~C:Type,~R:Type,~P:Data,~E:Data,~F:Type,~take:F -> F & Leaf.Stream<S,E>,~put:F -> Leaf.Stream<S,E> -> F,declaration:Event.Declaration<S,E>,world:W.World<S,C,R,P>,tick:Nat,returned:F & Leaf.Stream<S,E>) -> Route.Runtime<S,C,R,P,F> & Maybe<&2,List<&2,E>>:
22	  match returned:
23	    case (family,stream):restored(~S,~C,~R,~P,~E,~F,~take,~put,world,tick,family,declared(~S,~E,declaration,stream))
24	def get(~S:Data,~C:Type,~R:Type,~P:Data,~E:Data,~F:Type,~take:F -> F & Leaf.Stream<S,E>,~put:F -> Leaf.Stream<S,E> -> F,declaration:Event.Declaration<S,E>,owner:Route.Runtime<S,C,R,P,F>) -> Route.Runtime<S,C,R,P,F> & Maybe<&2,List<&2,E>>:
25	  match owner:
26	    case Route.Runtime{world,family,tick}:taken(~S,~C,~R,~P,~E,~F,~take,~put,declaration,world,tick,take(family))
27	def read(~S:Data,~C:Type,~R:Type,~P:Data,~E:Data,~F:Type,~take:F -> F & Leaf.Stream<S,E>,~put:F -> Leaf.Stream<S,E> -> F,declaration:Event.Declaration<S,E>) -> Cap.ValueRead<Route.Runtime<S,C,R,P,F>,Maybe<&2,List<&2,E>>>:
28	  Cap.ValueRead{owner => get(~S,~C,~R,~P,~E,~F,~take,~put,declaration,owner)}
29	def values(~S:Data,~C:Type,~R:Type,~P:Data,~E:Data,~F:Type,~take:F -> F & Leaf.Stream<S,E>,~put:F -> Leaf.Stream<S,E> -> F,declaration:Event.Declaration<S,E>,owner:Route.Runtime<S,C,R,P,F>) -> Route.Runtime<S,C,R,P,F> & Maybe<&2,List<&2,E>>:
30	  Cap.value_read_field(~Route.Runtime<S,C,R,P,F>,~Maybe<&2,List<&2,E>>,read(~S,~C,~R,~P,~E,~F,~take,~put,declaration))(owner)