Add a specific Exception when expression is empty

Author: codingseb

CodingSeb.ExpressionEvaluator/ExpressionEvaluator.cs

@@ -2848,6 +2848,9 @@ protected virtual bool EvaluateString(string expression, Stack<object> stack, re
 
         protected virtual object ProcessStack(Stack<object> stack)
         {
+            if (stack.Count == 0)
+                throw new ExpressionEvaluatorSyntaxErrorException("Empty expression or no token found");
+
             List<object> list = stack
                 .Select(e => e is ValueTypeNestingTrace valueTypeNestingTrace ? valueTypeNestingTrace.Value : e)
                 .Select(e => e is SubExpression subExpression ? Evaluate(subExpression.Expression) : e)
@@ -2964,7 +2967,6 @@ protected virtual object ProcessStack(Stack<object> stack)
 
             return stack.Pop();
         }
-
         #endregion
 
         #region Remove comments

TryWindow/MainWindow.xaml.cs

@@ -25,6 +25,8 @@ public MainWindow()
         {
             InitializeComponent();
 
+            new ExpressionEvaluator().Evaluate("");
+
             if (File.Exists(persistCodeFileName))
                 ScriptTextBox.Text = File.ReadAllText(persistCodeFileName);
             if (File.Exists(persistIterationFileName))