1	import Base
2	import entity_key.bend as Key
3	import ./world.bend as W
4	import ./string_equality.bend as Text
5	
6	# Lifetime metadata is separate from component owners and never proves liveness.
7	type Scope<-S:Data> is Data:
8	  Scope{namespace:U32,name:String}
9	type Member is Data:
10	  Member{name:String,id:Key.Key}
11	type Store<-S:Data,C:Type> is Type:
12	  Store{components:C,members:List<&2,Member>}
13	def empty(~S:Data,~C:Type,components:C) -> Store<S,C>:
14	  Store{components,[]}
15	def without(members:List<&2,Member>,+id:Key.Key) -> List<&2,Member>:
16	  match members:
17	    case []:[]
18	    case Member{+name,+mid} <> rest:
19	      +remaining = without(rest,id)
20	      Bool.pick(List<&2,Member>,Key.equal(mid,id),remaining,Member{name,mid} <> remaining)
21	def select(members:List<&2,Member>,+name:String) -> List<&2,Key.Key>:
22	  match members:
23	    case []:[]
24	    case Member{+key,+id} <> rest:
25	      +remaining = select(rest,name)
26	      Bool.pick(List<&2,Key.Key>,Text.equal(key,name),id <> remaining,remaining)
27	type SpawnResult<S:Data,P:Type> is Type:
28	  Spawned{handle:W.Handle<S>}
29	  SpawnRejected{payload:P,error:W.WorldError}