From 2e69035618e2c94a57a439740e5264e5a9974bb4 Mon Sep 17 00:00:00 2001
From: PopSlime <popslime@qq.com>
Date: Mon, 3 Apr 2023 17:00:05 +0800
Subject: [PATCH] Returns whether PDT evaluation succeeded.

---
 Assets/Cryville/Common/Pdt/PdtEvaluatorBase.cs | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/Assets/Cryville/Common/Pdt/PdtEvaluatorBase.cs b/Assets/Cryville/Common/Pdt/PdtEvaluatorBase.cs
index 525af57..63c3c0d 100644
--- a/Assets/Cryville/Common/Pdt/PdtEvaluatorBase.cs
+++ b/Assets/Cryville/Common/Pdt/PdtEvaluatorBase.cs
@@ -23,16 +23,18 @@ namespace Cryville.Common.Pdt {
 		/// </summary>
 		/// <param name="target">The target operator.</param>
 		/// <param name="exp">The expression to evaluate.</param>
-		public void Evaluate(PdtOperator target, PdtExpression exp) {
+		/// <returns>Whether the evaluaton succeeded.</returns>
+		public bool Evaluate(PdtOperator target, PdtExpression exp) {
 			_framecount = 0;
 			_goffset = 0;
 			_revokepttconst = false;
 			for (_rip = exp.Instructions.First; _rip != null; _rip = _rip.Next)
 				_rip.Value.Execute(this);
-			Operate(target, _framecount, true);
+			if (!Operate(target, _framecount, true)) return false;
 			if (exp.IsPotentialConstant) {
 				exp.IsConstant = exp.IsPotentialConstant = !_revokepttconst;
 			}
+			return true;
 		}
 		/// <summary>
 		/// Patches an expression with a lefthand variable and a compound operator.
@@ -184,7 +186,7 @@ namespace Cryville.Common.Pdt {
 		/// <returns>An operator of the specific name.</returns>
 		/// <remarks>The parameter count of the returned operator does not necessarily equal to <paramref name="pc" />.</remarks>
 		protected abstract PdtOperator GetOperator(PdtOperatorSignature sig);
-		unsafe void Operate(PdtOperator op, int pc, bool noset = false) {
+		unsafe bool Operate(PdtOperator op, int pc, bool noset = false) {
 			fixed (byte* pmem = _mem) {
 				op.Begin(this, pc);
 				for (int i = 0; i < pc; i++) {
@@ -192,12 +194,13 @@ namespace Cryville.Common.Pdt {
 					if (frame.Type == PdtInternalType.Error) {
 						_framecount -= pc - i;
 						_stack[_framecount++] = new StackFrame { Type = PdtInternalType.Error, Offset = _goffset, Length = 0 };
-						return;
+						return false;
 					}
 					op.LoadOperand(new PdtVariableMemory(frame.Type, pmem + frame.Offset, frame.Length));
 					_goffset -= frame.Length;
 				}
 				op.Call(pmem + _goffset, noset);
+				return true;
 			}
 		}
 		internal unsafe void Collapse(int name, LinkedListNode<PdtInstruction> target) {