新增UndefinedIdentifiersAsStrings

ExpressionElements/MemberElements/Identifier.cs

@@ -25,6 +25,7 @@ namespace Flee.ExpressionElements.MemberElements
         private PropertyDescriptor _myPropertyDescriptor;
         private Type _myVariableType;
         private Type _myCalcEngineReferenceType;
+        private bool _isStringLiteral;
         public IdentifierElement(string name)
         {
             this.MyName = name;
@@ -60,6 +61,13 @@ namespace Flee.ExpressionElements.MemberElements
 
             if (MyPrevious == null)
             {
+                // 检查是否启用了未定义标识符作为字符串的选项
+                if (MyOptions.UndefinedIdentifiersAsStrings)
+                {
+                    // 将此标识符标记为字符串字面量
+                    _isStringLiteral = true;
+                    return;
+                }
                 base.ThrowCompileException("NoIdentifierWithName", CompileExceptionReason.UndefinedName, MyName);
             }
             else
@@ -140,6 +148,13 @@ namespace Flee.ExpressionElements.MemberElements
         {
             base.Emit(ilg, services);
 
+            // 如果是字符串字面量，直接发出字符串加载指令
+            if (_isStringLiteral)
+            {
+                ilg.Emit(OpCodes.Ldstr, MyName);
+                return;
+            }
+
             this.EmitFirst(ilg);
 
             if ((_myCalcEngineReferenceType != null))
@@ -354,6 +369,12 @@ namespace Flee.ExpressionElements.MemberElements
         {
             get
             {
+                // 如果是字符串字面量，返回 string 类型
+                if (_isStringLiteral)
+                {
+                    return typeof(string);
+                }
+                
                 if ((_myCalcEngineReferenceType != null))
                 {
                     return _myCalcEngineReferenceType;