Implement optimization for collapse instruction.

Assets/Cryville/Crtr/RulesetSelectors.cs

@@ -1,9 +1,7 @@
 using Cryville.Common.Pdt;
-using Cryville.Crtr.Components;
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using System.Runtime.InteropServices;
 
 namespace Cryville.Crtr {
 	public class RulesetSelectors {
@@ -11,6 +9,11 @@ namespace Cryville.Crtr {
 		public RulesetSelectors(IEnumerable<RulesetSelector> s) {
 			selectors = s.ToArray();
 		}
+		public void Optimize(PdtEvaluatorBase etor) {
+			for (int i = 0; i < selectors.Length; i++) {
+				selectors[i].Optimize(etor);
+			}
+		}
 		public IEnumerable<ChartEvent> Match(ChartEvent ev) {
 			IEnumerable<ChartEvent> result = new ChartEvent[] { ev };
 			foreach (var sel in selectors) {
@@ -36,6 +39,7 @@ namespace Cryville.Crtr {
 	}
 
 	public abstract class RulesetSelector {
+		public virtual void Optimize(PdtEvaluatorBase etor) { }
 		public abstract IEnumerable<ChartEvent> Match(ChartEvent ev);
 		public class CreateItem : RulesetSelector {
 			public override string ToString() {
@@ -82,6 +86,9 @@ namespace Cryville.Crtr {
 			public override string ToString() {
 				return string.Format("> {{{0}}}", _exp);
 			}
+			public override void Optimize(PdtEvaluatorBase etor) {
+				etor.Optimize(_exp);
+			}
 			public override IEnumerable<ChartEvent> Match(ChartEvent ev) {
 				ChartPlayer.etor.ContextEvent = ev;
 				ChartPlayer.etor.Evaluate(_op, _exp);