1	import Base
2	
3	# Atom is the caller's schema-bound heterogeneous condition shape. Env is only
4	# captured machine metadata; the world and its component owners remain Type.
5	type Tree<Atom: Data> is Data:
6	  Leaf{atom: Atom}
7	  Constant{value: Bool}
8	  Negate{inner: Tree<Atom>}
9	  Both{left: Tree<Atom>,right: Tree<Atom>}
10	  Either{left: Tree<Atom>,right: Tree<Atom>}
11	
12	def all(~Atom: Data,items: List<&2,Tree<Atom>>) -> Tree<Atom>:
13	  match items:
14	    case Nil{}: Constant{True{}}
15	    case Con{head,tail}: Both{head,all(~Atom,tail)}
16	def any(~Atom: Data,items: List<&2,Tree<Atom>>) -> Tree<Atom>:
17	  match items:
18	    case Nil{}: Constant{False{}}
19	    case Con{head,tail}: Either{head,any(~Atom,tail)}
20	
21	def both_next(~Env: Data,first: Bool,env: Env,next: Env -> Bool) -> Bool:
22	  match first:
23	    case False{}: False{}
24	    case True{}: next(env)
25	def either_next(~Env: Data,first: Bool,env: Env,next: Env -> Bool) -> Bool:
26	  match first:
27	    case False{}: next(env)
28	    case True{}: True{}
29	
30	def evaluate(~Atom: Data,~Env: Data,~leaf: Atom -> Env -> Bool,tree: Tree<Atom>,+env: Env) -> Bool:
31	  match tree:
32	    case Leaf{atom}: leaf(atom,env)
33	    case Constant{value}: value
34	    case Negate{inner}: Bool.not(evaluate(~Atom,~Env,~leaf,inner,env))
35	    case Both{left,right}: both_next(~Env,evaluate(~Atom,~Env,~leaf,left,env),env,env => evaluate(~Atom,~Env,~leaf,right,env))
36	    case Either{left,right}: either_next(~Env,evaluate(~Atom,~Env,~leaf,left,env),env,env => evaluate(~Atom,~Env,~leaf,right,env))