Fix #116 and Performance/reduce allocations

.gitignore

@@ -1,7 +1,7 @@
 ## Ignore Visual Studio temporary files, build results, and
 ## files generated by popular Visual Studio add-ons.
 ##
-## Get latest from https://github.com/github/gitignore/blob/master/VisualStudio.gitignore
+## Get latest from https://github.com/github/gitignore/blob/main/VisualStudio.gitignore
 
 # User-specific files
 *.rsuser
@@ -43,6 +43,9 @@ Generated\ Files/
 [Tt]est[Rr]esult*/
 [Bb]uild[Ll]og.*
 
+# VisualStudio live unit testing
+*.lutconfig
+
 # NUnit
 *.VisualState.xml
 TestResult.xml

src/TextMateSharp.Tests/Grammar/StateStackTests.cs

@@ -0,0 +1,342 @@
+using NUnit.Framework;
+using TextMateSharp.Grammars;
+using TextMateSharp.Internal.Grammars;
+using TextMateSharp.Internal.Rules;
+
+namespace TextMateSharp.Tests.Grammar
+{
+    [TestFixture]
+    public class StateStackTests
+    {
+        private const int RuleIdSingleDepth = 42;
+        private const int RuleIdDepthTwo = 100;
+        private const int RuleIdDepthThree = 200;
+        private const int EnterPosition = 0;
+        private const int AnchorPosition = 0;
+
+        [Test]
+        public void ToString_SingleDepthState_ReturnsFormattedString()
+        {
+            // Arrange
+            StateStack stack = new StateStack(
+                null,
+                RuleId.Of(RuleIdSingleDepth),
+                EnterPosition,
+                AnchorPosition,
+                false,
+                null,
+                CreateTestScopeStack(),
+                CreateTestScopeStack());
+
+            const string expectedOutput = "[(42)]";
+
+            // Act
+            string result = stack.ToString();
+
+            // Assert
+            Assert.AreEqual(expectedOutput, result);
+        }
+
+        [Test]
+        public void ToString_TwoDepthState_ReturnsFormattedStringWithBothRules()
+        {
+            // Arrange
+            StateStack parent = new StateStack(
+                null,
+                RuleId.Of(RuleIdSingleDepth),
+                EnterPosition,
+                AnchorPosition,
+                false,
+                null,
+                CreateTestScopeStack(),
+                CreateTestScopeStack());
+
+            StateStack stack = parent.Push(
+                RuleId.Of(RuleIdDepthTwo),
+                EnterPosition,
+                AnchorPosition,
+                false,
+                null,
+                CreateTestScopeStack(),
+                CreateTestScopeStack());
+
+            const string expectedOutput = "[(42), (100)]";
+
+            // Act
+            string result = stack.ToString();
+
+            // Assert
+            Assert.AreEqual(expectedOutput, result);
+        }
+
+        [Test]
+        public void ToString_ThreeDepthState_ReturnsFormattedStringWithAllRules()
+        {
+            // Arrange
+            StateStack level1 = new StateStack(
+                null,
+                RuleId.Of(RuleIdSingleDepth),
+                EnterPosition,
+                AnchorPosition,
+                false,
+                null,
+                CreateTestScopeStack(),
+                CreateTestScopeStack());
+
+            StateStack level2 = level1.Push(
+                RuleId.Of(RuleIdDepthTwo),
+                EnterPosition,
+                AnchorPosition,
+                false,
+                null,
+                CreateTestScopeStack(),
+                CreateTestScopeStack());
+
+            StateStack level3 = level2.Push(
+                RuleId.Of(RuleIdDepthThree),
+                EnterPosition,
+                AnchorPosition,
+                false,
+                null,
+                CreateTestScopeStack(),
+                CreateTestScopeStack());
+
+            const string expectedOutput = "[(42), (100), (200)]";
+
+            // Act
+            string result = level3.ToString();
+
+            // Assert
+            Assert.AreEqual(expectedOutput, result);
+        }
+
+        [Test]
+        public void ToString_NullStaticInstance_ReturnsFormattedNoRuleString()
+        {
+            // Arrange
+            StateStack stack = StateStack.NULL;
+            const string expectedOutput = "[(0)]";
+
+            // Act
+            string result = stack.ToString();
+
+            // Assert
+            Assert.AreEqual(expectedOutput, result);
+        }
+
+        [Test]
+        public void ToString_StateWithNoRuleId_ReturnsFormattedNoRuleString()
+        {
+            // Arrange
+            StateStack stack = new StateStack(
+                null,
+                RuleId.NO_RULE,
+                EnterPosition,
+                AnchorPosition,
+                false,
+                null,
+                CreateTestScopeStack(),
+                CreateTestScopeStack());
+
+            const string expectedOutput = "[(0)]";
+
+            // Act
+            string result = stack.ToString();
+
+            // Assert
+            Assert.AreEqual(expectedOutput, result);
+        }
+
+        [Test]
+        public void ToString_StateWithEndRuleId_ReturnsFormattedEndRuleString()
+        {
+            // Arrange
+            StateStack stack = new StateStack(
+                null,
+                RuleId.END_RULE,
+                EnterPosition,
+                AnchorPosition,
+                false,
+                null,
+                CreateTestScopeStack(),
+                CreateTestScopeStack());
+
+            const string expectedOutput = "[(-1)]";
+
+            // Act
+            string result = stack.ToString();
+
+            // Assert
+            Assert.AreEqual(expectedOutput, result);
+        }
+
+        [Test]
+        public void ToString_StateWithWhileRuleId_ReturnsFormattedWhileRuleString()
+        {
+            // Arrange
+            StateStack stack = new StateStack(
+                null,
+                RuleId.WHILE_RULE,
+                EnterPosition,
+                AnchorPosition,
+                false,
+                null,
+                CreateTestScopeStack(),
+                CreateTestScopeStack());
+
+            const string expectedOutput = "[(-2)]";
+
+            // Act
+            string result = stack.ToString();
+
+            // Assert
+            Assert.AreEqual(expectedOutput, result);
+        }
+
+        [Test]
+        public void ToString_BoundaryDepthZero_ReturnsNullStackString()
+        {
+            // Arrange - depth 0 returns StateStack.NULL
+            const int depthZero = 0;
+            StateStack stack = CreateStateStackWithDepth(depthZero);
+            const string expectedOutput = "[(0)]";
+
+            // Act
+            string result = stack.ToString();
+
+            // Assert
+            Assert.AreEqual(expectedOutput, result);
+            Assert.AreSame(StateStack.NULL, stack);
+        }
+
+        [Test]
+        public void ToString_BoundaryDepthOne_ReturnsSinglePushString()
+        {
+            // Arrange - depth 1 is one push on NULL
+            const int depthOne = 1;
+            StateStack stack = CreateStateStackWithDepth(depthOne);
+            const string expectedOutput = "[(0), (0)]";
+
+            // Act
+            string result = stack.ToString();
+
+            // Assert
+            Assert.AreEqual(expectedOutput, result);
+        }
+
+        [Test]
+        public void ToString_BoundaryVeryLargeDepth_ReturnsFormattedStringWithAllLevels()
+        {
+            // Arrange - test large depth to verify performance and correctness
+            const int veryLargeDepth = 100;
+            StateStack stack = CreateStateStackWithDepth(veryLargeDepth);
+
+            // Act
+            string result = stack.ToString();
+
+            // Assert
+            Assert.IsNotNull(result);
+            Assert.IsTrue(result.StartsWith("[(0)"));
+            Assert.IsTrue(result.EndsWith("(9900)]"));
+
+            // Verify correct number of elements: NULL (1) + 100 pushes = 101 elements
+            const int expectedCommaCount = 100;
+            int actualCommaCount = result.Split(',').Length - 1;
+            Assert.AreEqual(expectedCommaCount, actualCommaCount);
+        }
+
+        [Test]
+        public void ToString_CalledMultipleTimes_ReturnsSameResult()
+        {
+            // Arrange
+            StateStack stack = new StateStack(
+                null,
+                RuleId.Of(RuleIdSingleDepth),
+                EnterPosition,
+                AnchorPosition,
+                false,
+                null,
+                CreateTestScopeStack(),
+                CreateTestScopeStack());
+
+            // Act
+            string result1 = stack.ToString();
+            string result2 = stack.ToString();
+            string result3 = stack.ToString();
+
+            // Assert
+            Assert.AreEqual(result1, result2);
+            Assert.AreEqual(result2, result3);
+        }
+
+        [Test]
+        public void ToString_StackWithMixedRuleIds_ReturnsCorrectOrderFromRootToCurrent()
+        {
+            // Arrange
+            StateStack root = new StateStack(
+                null,
+                RuleId.Of(RuleIdSingleDepth),
+                EnterPosition,
+                AnchorPosition,
+                false,
+                null,
+                CreateTestScopeStack(),
+                CreateTestScopeStack());
+
+            StateStack middle = root.Push(
+                RuleId.Of(RuleIdDepthTwo),
+                EnterPosition,
+                AnchorPosition,
+                false,
+                null,
+                CreateTestScopeStack(),
+                CreateTestScopeStack());
+
+            StateStack current = middle.Push(
+                RuleId.Of(RuleIdDepthThree),
+                EnterPosition,
+                AnchorPosition,
+                false,
+                null,
+                CreateTestScopeStack(),
+                CreateTestScopeStack());
+
+            const string expectedOutput = "[(42), (100), (200)]";
+
+            // Act
+            string result = current.ToString();
+
+            // Assert
+            Assert.AreEqual(expectedOutput, result);
+        }
+
+        #region Helper Methods
+
+        private static AttributedScopeStack CreateTestScopeStack()
+        {
+            return new AttributedScopeStack(null, "test.scope", 0);
+        }
+
+        private static StateStack CreateStateStackWithDepth(int depth)
+        {
+            StateStack stack = StateStack.NULL;
+            const int ruleIdDepthMultiplier = 100;
+            for (int depthIndex = 0; depthIndex < depth; depthIndex++)
+            {
+                int ruleId = depthIndex * ruleIdDepthMultiplier;
+                stack = stack.Push(
+                    RuleId.Of(ruleId),
+                    EnterPosition,
+                    AnchorPosition,
+                    false,
+                    null,
+                    CreateTestScopeStack(),
+                    CreateTestScopeStack());
+            }
+
+            return stack;
+        }
+
+        #endregion
+    }
+}