1	import Base
2	import ./world.bend as W
3	
4	# Remove exact registration identity, preserving every other system instance.
5	# IDs are monotonic and are not recycled by disposal.
6	def retained(keep: Bool,meta: W.RegistrationMeta,rest: List<&2,W.RegistrationMeta>) -> List<&2,W.RegistrationMeta>:
7	  match keep:
8	    case True{}: meta <> rest
9	    case False{}: rest
10	
11	def without(registrations: List<&2,W.RegistrationMeta>,+id: U32,+name: String,+access: List<&2,String>) -> List<&2,W.RegistrationMeta>:
12	  match registrations:
13	    case []: []
14	    case +meta <> rest: retained(Bool.not(W.registration_meta_matches(meta,id,name,access)),meta,without(rest,id,name,access))
15	
16	def remove_checked(~S: Data,~Store: Type,~R: Type,~E: Data,allowed: Bool,world: W.World<S,Store,R,E>,+id: U32,+name: String,+access: List<&2,String>) -> W.World<S,Store,R,E> & Bool:
17	  match allowed world:
18	    case False{} world: (world,False{})
19	    case True{} W.World{namespace,allocator,store,resource,events,pending,registrations,nextSystemId,clock}: (W.World{namespace,allocator,store,resource,events,pending,without(registrations,id,name,access),nextSystemId,clock},True{})
20	
21	def remove(~S: Data,~Store: Type,~R: Type,~E: Data,world: W.World<S,Store,R,E>,namespace: U32,+id: U32,+name: String,+access: List<&2,String>) -> W.World<S,Store,R,E> & Bool:
22	  match world:
23	    case W.World{+actual,allocator,store,resource,events,pending,+registrations,nextSystemId,clock}: remove_checked(~S,~Store,~R,~E,Bool.and(U32.is_eq(namespace,actual),W.registration_list_matches(registrations,id,name,access)),W.World{actual,allocator,store,resource,events,pending,registrations,nextSystemId,clock},id,name,access)