Exception cleanup. Code cleanup.

Assets/Cryville/Common/Pdt/PdtOperator.cs

@@ -19,7 +19,8 @@ namespace Cryville.Common.Pdt {
 		/// <returns>The operand at the specified index.</returns>
 		/// <exception cref="IndexOutOfRangeException"><paramref name="index" /> is not less than <see cref="LoadedOperandCount" /> or less than 0.</exception>
 		protected PdtVariableMemory GetOperand(int index) {
-			if (index >= LoadedOperandCount || index < 0) throw new IndexOutOfRangeException();
+			if (index >= LoadedOperandCount || index < 0)
+				throw new ArgumentOutOfRangeException("index");
 			int i = index + _loadindex;
 			return _operands[i];
 		}
@@ -33,11 +34,9 @@ namespace Cryville.Common.Pdt {
 			_operands = new PdtVariableMemory[pc];
 		}
 		PdtEvaluatorBase _etor;
-		bool _failure = false;
 		bool _rfreq = true;
 		internal void Begin(PdtEvaluatorBase etor) {
 			_etor = etor;
-			_failure = false;
 			_loadindex = ParamCount;
 		}
 		internal void LoadOperand(PdtVariableMemory mem) {
@@ -51,10 +50,6 @@ namespace Cryville.Common.Pdt {
 				if (_rfreq) _etor.DiscardStack();
 				throw new InvalidOperationException("Evaluation failed", ex);
 			}
-			if (_failure) {
-				if (_rfreq) _etor.DiscardStack();
-				throw new InvalidOperationException("Evaluation failed");
-			}
 			if (!_rfreq && !noset) throw new InvalidOperationException("Return frame not set");
 		}
 		/// <summary>
@@ -69,10 +64,7 @@ namespace Cryville.Common.Pdt {
 		/// <returns>The return frame.</returns>
 		/// <exception cref="InvalidOperationException">The return frame has already been requested.</exception>
 		protected PdtVariableMemory GetReturnFrame(int type, int len) {
-			if (_rfreq) {
-				_failure = true;
-				throw new InvalidOperationException("Return frame already requested");
-			}
+			if (_rfreq) throw new InvalidOperationException("Return frame requested twice");
 			_rfreq = true;
 			return _etor.StackAlloc(type, _prmem, len);
 		}