1	import Base
2	import ./machine.bend as M
3	import ./machine_queue.bend as Queue
4	import ./execution_machine_stream.bend as Stream
5	import ./change_tick.bend as Tick
6	
7	# The Cell is framework storage. Ordinary bodies receive declaration-derived ops.
8	type Cell<-S:Data,-K:Data,-V:Data> is Type:
9	  Cell{slot:M.Slot<S,K,V>,stream:Stream.Store<V>,revision:Nat,stamp:Maybe<&2,Tick.Tick>,nextStamp:Maybe<&2,Tick.Tick>,sequence:Nat,initialPending:Bool,namespace:Maybe<&2,U32>,intent:Intent<V>}
10	type Intent<-V:Data> is Data:
11	  Idle{}
12	  Initial{value:V}
13	  Transition{from:V,to:V,runExitEnter:Bool}
14	type View<-S:Data,-K:Data,-V:Data> is Data:
15	  View{current:M.CurrentView<S,K,V>,next:M.NextView<S,K,V>,revision:Nat,stamp:Maybe<&2,Tick.Tick>,nextStamp:Maybe<&2,Tick.Tick>,intent:Intent<V>}
16	def empty(~S:Data,~K:Data,~V:Data) -> Cell<S,K,V>:
17	  Cell{M.Missing{},Stream.empty(~V),0n,None{},None{},0n,False{},None{},Idle{}}
18	def projected(-S:Data,-K:Data,-V:Data,cell:Cell<S,K,V>) -> Cell<S,K,V> & View<S,K,V>:
19	  match cell:
20	    case Cell{+slot,stream,+revision,+stamp,+nextStamp,sequence,initialPending,namespace,+intent}:(Cell{slot,stream,revision,stamp,nextStamp,sequence,initialPending,namespace,intent},View{M.current_view_generic(S,K,V,slot),M.next_view_generic(S,K,V,slot),revision,stamp,nextStamp,intent})
21	def queue_generic(-S:Data,-K:Data,-V:Data,same:V -> V -> Bool,cell:Cell<S,K,V>,request:M.QueueInput<V>) -> Cell<S,K,V>:
22	  match cell request:
23	    case Cell{slot,stream,revision,stamp,nextStamp,sequence,initialPending,namespace,intent} M.Set{value,skipSame}:Cell{Queue.queue_generic(S,K,V,same,slot,value,skipSame),stream,revision,stamp,nextStamp,sequence,initialPending,namespace,intent}
24	    case Cell{slot,stream,revision,stamp,nextStamp,sequence,initialPending,namespace,intent} M.Reset{}:Cell{M.reset_generic(S,K,V,slot),stream,revision,stamp,nextStamp,sequence,initialPending,namespace,intent}
25	# Next setters and pending consumption have their own actual write stamp:
26	# https://github.com/bevyengine/bevy/blob/ad678262ce53b5d142fe49ee5e08caff6f00ab60/crates/bevy_state/src/state/resources.rs#L197-L234
27	def queue(~S:Data,~K:Data,~V:Data,~same:V -> V -> Bool,cell:Cell<S,K,V>,request:M.QueueInput<V>) -> Cell<S,K,V>:
28	  queue_generic(S,K,V,same,cell,request)
29	
30	def request_stamped_generic(-S:Data,-K:Data,-V:Data,tick:Tick.Tick,cell:Cell<S,K,V>) -> Cell<S,K,V> & Unit:
31	  match cell:
32	    case Cell{M.Missing{},stream,revision,stamp,nextStamp,sequence,initialPending,namespace,intent}:(Cell{M.Missing{},stream,revision,stamp,nextStamp,sequence,initialPending,namespace,intent},Unit{})
33	    case Cell{slot,stream,revision,stamp,_,sequence,initialPending,namespace,intent}:(Cell{slot,stream,revision,stamp,Some{tick},sequence,initialPending,namespace,intent},Unit{})
34	def request_stamped(~S:Data,~K:Data,~V:Data,tick:Tick.Tick,cell:Cell<S,K,V>) -> Cell<S,K,V> & Unit:
35	  request_stamped_generic(S,K,V,tick,cell)
36	
37	def queued_at_generic(-S:Data,-K:Data,-V:Data,same:V -> V -> Bool,request:M.QueueInput<V>,tick:Tick.Tick,cell:Cell<S,K,V>) -> Cell<S,K,V> & Unit:
38	  request_stamped_generic(S,K,V,tick,queue_generic(S,K,V,same,cell,request))
39	def queued_at(~S:Data,~K:Data,~V:Data,~same:V -> V -> Bool,request:M.QueueInput<V>,tick:Tick.Tick,cell:Cell<S,K,V>) -> Cell<S,K,V> & Unit:
40	  queued_at_generic(S,K,V,same,request,tick,cell)
41	
42	def initialized(~S:Data,~K:Data,~V:Data,+value:V,+tick:Tick.Tick,stream:Stream.Store<V>,+sequence:Nat,namespace:Maybe<&2,U32>) -> Cell<S,K,V>:
43	  Cell{M.Present{value,M.NoPending{},None{},True{}},Stream.publish(~V,stream,1n+sequence,M.Initial{value}),1n,Some{tick},Some{tick},1n+sequence,True{},namespace,Initial{value}}
44	def initialize(~S:Data,~K:Data,~V:Data,cell:Cell<S,K,V>,value:V,tick:Tick.Tick) -> Cell<S,K,V>:
45	  match cell:
46	    case Cell{M.Missing{},stream,_,_,_,sequence,_,namespace,_}:initialized(~S,~K,~V,value,tick,stream,sequence,namespace)
47	    case cell:cell
48	def next_revision(same:Bool,revision:Nat) -> Nat:
49	  match same:
50	    case True{}:revision
51	    case False{}:1n+revision
52	def next_stamp(same:Bool,stamp:Maybe<&2,Tick.Tick>,tick:Tick.Tick) -> Maybe<&2,Tick.Tick>:
53	  match same:
54	    case True{}:stamp
55	    case False{}:Some{tick}
56	# Bevy commits State and emits StateTransitionEvent before phase schedules:
57	# https://github.com/bevyengine/bevy/blob/ad678262ce53b5d142fe49ee5e08caff6f00ab60/crates/bevy_state/src/state/transitions.rs#L138-L205
58	# Comparator equality retains actual Current; exited/Previous/event use the
59	# requested value, including when equal values have different representations.
60	def retained(~V:Data,equal:Bool,from:V,to:V) -> V:
61	  match equal:
62	    case True{}:from
63	    case False{}:to
64	def exited(~V:Data,equal:Bool,from:V,to:V) -> V:
65	  match equal:
66	    case True{}:to
67	    case False{}:from
68	def committed(~S:Data,~K:Data,~V:Data,+from:V,+to:V,skipSame:Bool,stream:Stream.Store<V>,revision:Nat,stamp:Maybe<&2,Tick.Tick>,+sequence:Nat,+tick:Tick.Tick,+equal:Bool,namespace:Maybe<&2,U32>) -> Cell<S,K,V>:
69	  Cell{M.Present{retained(~V,equal,from,to),M.NoPending{},Some{exited(~V,equal,from,to)},Bool.not(equal)},Stream.publish(~V,stream,1n+sequence,M.Transition{exited(~V,equal,from,to),to}),next_revision(equal,revision),next_stamp(equal,stamp,tick),Some{tick},1n+sequence,False{},namespace,Transition{exited(~V,equal,from,to),to,Bool.or(Bool.not(skipSame),Bool.not(equal))}}
70	def apply(~S:Data,~K:Data,~V:Data,~same:V -> V -> Bool,cell:Cell<S,K,V>,tick:Tick.Tick) -> Cell<S,K,V>:
71	  match cell:
72	    case Cell{M.Present{+current,M.Queued{+value,skipSame},_,_},stream,revision,stamp,nextStamp,sequence,_,namespace,_}:committed(~S,~K,~V,current,value,skipSame,stream,revision,stamp,sequence,tick,same(current,value),namespace)
73	    case Cell{slot,stream,revision,stamp,nextStamp,sequence,True{},namespace,intent}:Cell{slot,stream,revision,stamp,nextStamp,sequence,False{},namespace,intent}
74	    case Cell{slot,stream,revision,stamp,nextStamp,sequence,False{},namespace,_}:Cell{M.clear_changed(~S,~K,~V,slot),stream,revision,stamp,nextStamp,sequence,False{},namespace,Idle{}}
75	def run_exit(-V:Data,intent:Intent<V>) -> Bool:
76	  match intent:
77	    case Transition{_,_,allowed}:allowed
78	    case _:False{}
79	def run_transition(-V:Data,intent:Intent<V>) -> Bool:
80	  match intent:
81	    case Transition{_,_,_}:True{}
82	    case _:False{}
83	def run_enter(-V:Data,intent:Intent<V>) -> Bool:
84	  match intent:
85	    case Initial{_}:True{}
86	    case Transition{_,_,allowed}:allowed
87	    case _:False{}
88	def matches(~S:Data,~K:Data,~V:Data,~same:V -> V -> Bool,value:V,view:View<S,K,V>) -> Bool:
89	  match view:
90	    case View{current,_,_,_,_,_}:M.is_current(~S,~K,~V,~same,current,value)
91	
92	def bind(~S:Data,~K:Data,~V:Data,namespace:U32,cell:Cell<S,K,V>) -> Cell<S,K,V>:
93	  match cell:
94	    case Cell{slot,stream,revision,stamp,nextStamp,sequence,initialPending,None{},intent}:Cell{slot,stream,revision,stamp,nextStamp,sequence,initialPending,Some{namespace},intent}
95	    case cell:cell
96	def maintain(~S:Data,~K:Data,~V:Data,tick:Tick.Tick,cell:Cell<S,K,V>) -> Cell<S,K,V>:
97	  match cell:
98	    case Cell{slot,stream,revision,stamp,nextStamp,+sequence,initialPending,namespace,intent}:Cell{slot,Stream.maintain(~V,sequence,tick,stream),revision,stamp,nextStamp,sequence,initialPending,namespace,intent}