Implement compound operator patching.

Assets/Cryville/Common/Pdt/PdtEvaluatorBase.cs

@@ -34,6 +34,16 @@ namespace Cryville.Common.Pdt {
 			}
 		}
 		/// <summary>
+		/// Patches an expression with a lefthand variable and a compound operator.
+		/// </summary>
+		/// <param name="target">The name of the lefthand variable.</param>
+		/// <param name="op">The name of the compound operator.</param>
+		/// <param name="exp">The expression.</param>
+		public void PatchCompound(int target, int op, PdtExpression exp) {
+			exp.Instructions.AddFirst(new PdtInstruction.PushVariable(target));
+			exp.Instructions.AddLast(new PdtInstruction.Operate(op, 2));
+		}
+		/// <summary>
 		/// Optimizes an expression by merging its instructions.
 		/// </summary>
 		/// <param name="exp">The expression to optimize.</param>

Assets/Cryville/Common/Pdt/PdtExpression.cs

@@ -51,9 +51,8 @@ namespace Cryville.Common.Pdt {
 		}
 		public class PushVariable : PdtInstruction {
 			public int Name { get; private set; }
-			public PushVariable(string name) {
+			public PushVariable(int name) { Name = name; }
-				Name = IdentifierManager.SharedInstance.Request(name);
+			public PushVariable(string name) : this(IdentifierManager.SharedInstance.Request(name)) { }
-			}
 			internal override void Execute(PdtEvaluatorBase etor) {
 				etor.PushVariable(Name);
 			}
@@ -63,6 +62,9 @@ namespace Cryville.Common.Pdt {
 		}
 		public class Operate : PdtInstruction {
 			public PdtOperatorSignature Signature { get; private set; }
+			public Operate(int name, int paramCount) {
+				Signature = new PdtOperatorSignature(name, paramCount);
+			}
 			public Operate(string name, int paramCount) {
 				Signature = new PdtOperatorSignature(name, paramCount);
 			}