1	import Base
2	import ./world.bend as W
3	import ./entity_key_render.bend as KeyRender
4	import ./trace_facts.bend as Facts
5	
6	def error(error:W.WorldError) -> String:
7	  match error:
8	    case W.MissingEntity{}:"MissingEntity"
9	    case W.CapacityExceeded{}:"CapacityExceeded"
10	    case W.NamespaceExhausted{}:"NamespaceExhausted"
11	    case W.SystemIdExhausted{}:"SystemIdExhausted"
12	def handle(~S:Data,target:W.Handle<S>) -> String:
13	  match target:
14	    case W.Handle{namespace,key}:U32.show(namespace) ++ ":" ++ KeyRender.show(key)
15	def deferred(~S:Data,state:Facts.State,key:String,operation:Facts.Operation,target:W.Handle<S>,result:Facts.FactResult) -> Facts.State:
16	  match state:
17	    case Facts.Off{}:Facts.Off{}
18	    case Facts.On{facts}:Facts.On{Facts.Fact{Facts.DeferredCommand{},key,operation,Some{handle(~S,target)},Facts.OpaqueValue{},Facts.OpaqueValue{},result} <> facts}
19	def applied(~S:Data,state:Facts.State,key:String,target:W.Handle<S>,status:W.Status) -> Facts.State:
20	  match state status:
21	    case Facts.Off{} _:Facts.Off{}
22	    case state W.Accepted{}:deferred(~S,state,key,Facts.ApplyOperation{},target,Facts.Applied{})
23	    case state W.Rejected{why}:deferred(~S,state,key,Facts.ApplyOperation{},target,Facts.Refused{error(why)})