From ab5c3a48a8091e4bf7954428ecfc958683b41ed9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Asko=20N=C3=B5mm?= <asko@nth.ee>
Date: Thu, 17 Oct 2024 16:49:50 +0300
Subject: [PATCH 1/5] Implement expression validator.

---
 Htmt/AttributeParsers/ForAttributeParser.cs   |   4 +-
 .../GenericValueAttributeParser.cs            |   2 +-
 Htmt/AttributeParsers/IfAttributeParser.cs    |  57 +++++---
 .../InnerHtmlAttributeParser.cs               |   2 +-
 .../InnerTextAttributeParser.cs               |   2 +-
 .../OuterHtmlAttributeParser.cs               |   2 +-
 .../OuterTextAttributeParser.cs               |   2 +-
 .../AttributeParsers/UnlessAttributeParser.cs |  47 ++++---
 Htmt/ExpressionValidator.cs                   | 125 +++++++++++++++++
 Htmt/Helper.cs                                |   4 +-
 Htmt/IAttributeParser.cs                      |   2 +-
 Htmt/Parser.cs                                |   4 +-
 HtmtTests/AttributeParserTest.cs              |  24 +++-
 HtmtTests/ExpressionValidatorTest.cs          | 127 ++++++++++++++++++
 HtmtTests/HelperTest.cs                       |   6 +-
 15 files changed, 359 insertions(+), 51 deletions(-)
 create mode 100644 Htmt/ExpressionValidator.cs
 create mode 100644 HtmtTests/ExpressionValidatorTest.cs

diff --git a/Htmt/AttributeParsers/ForAttributeParser.cs b/Htmt/AttributeParsers/ForAttributeParser.cs
index bb40950..ddf37ff 100644
--- a/Htmt/AttributeParsers/ForAttributeParser.cs
+++ b/Htmt/AttributeParsers/ForAttributeParser.cs
@@ -6,7 +6,7 @@ public class ForAttributeParser : IAttributeParser
 {
     public string XTag => "//*[@x:for]";
     
-    public void Parse(XmlDocument xml, Dictionary<string, object> data, XmlNodeList? nodes)
+    public void Parse(XmlDocument xml, Dictionary<string, object?> data, XmlNodeList? nodes)
     {
         // No nodes found
         if (nodes == null || nodes.Count == 0)
@@ -31,7 +31,7 @@ public void Parse(XmlDocument xml, Dictionary<string, object> data, XmlNodeList?
 
             foreach (var item in enumerable)
             {
-                var iterationData = new Dictionary<string, object>(data);
+                var iterationData = new Dictionary<string, object?>(data);
 
                 if (!string.IsNullOrEmpty(asVar))
                 {
diff --git a/Htmt/AttributeParsers/GenericValueAttributeParser.cs b/Htmt/AttributeParsers/GenericValueAttributeParser.cs
index de0d88e..2419939 100644
--- a/Htmt/AttributeParsers/GenericValueAttributeParser.cs
+++ b/Htmt/AttributeParsers/GenericValueAttributeParser.cs
@@ -6,7 +6,7 @@ public class GenericValueAttributeParser : IAttributeParser
 {
     public string XTag => "//*[@*[starts-with(name(), 'x:')]]";
     
-    public void Parse(XmlDocument xml, Dictionary<string, object> data, XmlNodeList? nodes)
+    public void Parse(XmlDocument xml, Dictionary<string, object?> data, XmlNodeList? nodes)
     {
         // No nodes found
         if (nodes == null || nodes.Count == 0)
diff --git a/Htmt/AttributeParsers/IfAttributeParser.cs b/Htmt/AttributeParsers/IfAttributeParser.cs
index 4d7654e..df8ec00 100644
--- a/Htmt/AttributeParsers/IfAttributeParser.cs
+++ b/Htmt/AttributeParsers/IfAttributeParser.cs
@@ -7,7 +7,7 @@ public class IfAttributeParser : IAttributeParser
 {
     public string XTag => "//*[@x:if]";
     
-    public void Parse(XmlDocument xml, Dictionary<string, object> data, XmlNodeList? nodes)
+    public void Parse(XmlDocument xml, Dictionary<string, object?> data, XmlNodeList? nodes)
     {
         // No nodes found
         if (nodes == null || nodes.Count == 0)
@@ -21,30 +21,47 @@ public void Parse(XmlDocument xml, Dictionary<string, object> data, XmlNodeList?
 
             var key = n.GetAttribute("x:if");
             n.RemoveAttribute("x:if");
-            var value = Helper.FindValueByKeys(data, key.Split('.'));
             
-            // Remove node if value is null
-            if(value == null)
+            // if key is a single word, we just check for a truthy value
+            if (!key.Contains(' '))
             {
-                n.ParentNode?.RemoveChild(n);
-                continue;
+                var value = Helper.FindValueByKeys(data, key.Split('.'));
+
+                // Remove node if value is null
+                if (value == null)
+                {
+                    n.ParentNode?.RemoveChild(n);
+                    continue;
+                }
+
+                // Remove node if value is falsey
+                var removeNode = value switch
+                {
+                    bool b => !b,
+                    int i => i == 0,
+                    double d => d == 0,
+                    string s => string.IsNullOrEmpty(s),
+                    IEnumerable<object> e => !e.Any(),
+                    IDictionary d => d.Count == 0,
+                    _ => false
+                };
+
+                if (removeNode)
+                {
+                    n.ParentNode?.RemoveChild(n);
+                }
             }
             
-            // Remove node if value is falsey
-            var removeNode = value switch
+            // if key contains multiple words, evaluate the expression with ExpressionValidator
+            else
             {
-                bool b => !b,
-                int i => i == 0,
-                double d => d == 0,
-                string s => string.IsNullOrEmpty(s),
-                IEnumerable<object> e => !e.Any(),
-                IDictionary d => d.Count == 0,
-                _ => false
-            };
-            
-            if (removeNode)
-            {
-                n.ParentNode?.RemoveChild(n);
+                var expression = new ExpressionValidator(key);
+                var result = expression.Validates(data);
+
+                if (!result)
+                {
+                    n.ParentNode?.RemoveChild(n);
+                }
             }
         }
     }
diff --git a/Htmt/AttributeParsers/InnerHtmlAttributeParser.cs b/Htmt/AttributeParsers/InnerHtmlAttributeParser.cs
index d0eeab6..2dbeb38 100644
--- a/Htmt/AttributeParsers/InnerHtmlAttributeParser.cs
+++ b/Htmt/AttributeParsers/InnerHtmlAttributeParser.cs
@@ -7,7 +7,7 @@ public class InnerHtmlAttributeParser: IAttributeParser
 {
     public string XTag => "//*[@x:inner-html]";
     
-    public void Parse(XmlDocument xml, Dictionary<string, object> data, XmlNodeList? nodes)
+    public void Parse(XmlDocument xml, Dictionary<string, object?> data, XmlNodeList? nodes)
     {
         // No nodes found
         if (nodes == null || nodes.Count == 0)
diff --git a/Htmt/AttributeParsers/InnerTextAttributeParser.cs b/Htmt/AttributeParsers/InnerTextAttributeParser.cs
index 147fbe7..bfc6ac3 100644
--- a/Htmt/AttributeParsers/InnerTextAttributeParser.cs
+++ b/Htmt/AttributeParsers/InnerTextAttributeParser.cs
@@ -7,7 +7,7 @@ public class InnerTextAttributeParser : IAttributeParser
 {
     public string XTag => "//*[@x:inner-text]";
     
-    public void Parse(XmlDocument xml, Dictionary<string, object> data, XmlNodeList? nodes)
+    public void Parse(XmlDocument xml, Dictionary<string, object?> data, XmlNodeList? nodes)
     {
         // No nodes found
         if (nodes == null || nodes.Count == 0)
diff --git a/Htmt/AttributeParsers/OuterHtmlAttributeParser.cs b/Htmt/AttributeParsers/OuterHtmlAttributeParser.cs
index 4581e3f..850ffe6 100644
--- a/Htmt/AttributeParsers/OuterHtmlAttributeParser.cs
+++ b/Htmt/AttributeParsers/OuterHtmlAttributeParser.cs
@@ -6,7 +6,7 @@ public class OuterHtmlAttributeParser : IAttributeParser
 {
     public string XTag => "//*[@x:outer-html]";
     
-    public void Parse(XmlDocument xml, Dictionary<string, object> data, XmlNodeList? nodes)
+    public void Parse(XmlDocument xml, Dictionary<string, object?> data, XmlNodeList? nodes)
     {
         // No nodes found
         if (nodes == null || nodes.Count == 0)
diff --git a/Htmt/AttributeParsers/OuterTextAttributeParser.cs b/Htmt/AttributeParsers/OuterTextAttributeParser.cs
index c0db626..0c8ec81 100644
--- a/Htmt/AttributeParsers/OuterTextAttributeParser.cs
+++ b/Htmt/AttributeParsers/OuterTextAttributeParser.cs
@@ -7,7 +7,7 @@ public partial class OuterTextAttributeParser : IAttributeParser
 {
     public string XTag => "//*[@x:outer-text]";
     
-    public void Parse(XmlDocument xml, Dictionary<string, object> data, XmlNodeList? nodes)
+    public void Parse(XmlDocument xml, Dictionary<string, object?> data, XmlNodeList? nodes)
     {
         // No nodes found
         if (nodes == null || nodes.Count == 0)
diff --git a/Htmt/AttributeParsers/UnlessAttributeParser.cs b/Htmt/AttributeParsers/UnlessAttributeParser.cs
index 13abfed..b53f0f6 100644
--- a/Htmt/AttributeParsers/UnlessAttributeParser.cs
+++ b/Htmt/AttributeParsers/UnlessAttributeParser.cs
@@ -7,7 +7,7 @@ public class UnlessAttributeParser : IAttributeParser
 {
     public string XTag => "//*[@x:unless]";
     
-    public void Parse(XmlDocument xml, Dictionary<string, object> data, XmlNodeList? nodes)
+    public void Parse(XmlDocument xml, Dictionary<string, object?> data, XmlNodeList? nodes)
     {
         // No nodes found
         if (nodes == null || nodes.Count == 0)
@@ -21,22 +21,39 @@ public void Parse(XmlDocument xml, Dictionary<string, object> data, XmlNodeList?
 
             var key = n.GetAttribute("x:unless");
             n.RemoveAttribute("x:unless");
-            var value = Helper.FindValueByKeys(data, key.Split('.'));
-
-            var removeNode = value switch
+            
+            // if key is a single word, we just check for a truthy value
+            if (!key.Contains(' '))
             {
-                bool b => b,
-                int i => i != 0,
-                double d => d != 0,
-                string s => !string.IsNullOrEmpty(s),
-                IEnumerable<object> e => e.Any(),
-                IDictionary d => d.Count > 0,
-                _ => true
-            };
-
-            if (removeNode)
+                var value = Helper.FindValueByKeys(data, key.Split('.'));
+
+                var removeNode = value switch
+                {
+                    bool b => b,
+                    int i => i != 0,
+                    double d => d != 0,
+                    string s => !string.IsNullOrEmpty(s),
+                    IEnumerable<object> e => e.Any(),
+                    IDictionary d => d.Count > 0,
+                    _ => true
+                };
+
+                if (removeNode)
+                {
+                    n.ParentNode?.RemoveChild(n);
+                }
+            }
+
+            // if key contains multiple words, evaluate the expression with ExpressionValidator
+            else
             {
-                n.ParentNode?.RemoveChild(n);
+                var expression = new ExpressionValidator(key);
+                var result = expression.Validates(data);
+
+                if (result)
+                {
+                    n.ParentNode?.RemoveChild(n);
+                }
             }
         }
     }
diff --git a/Htmt/ExpressionValidator.cs b/Htmt/ExpressionValidator.cs
new file mode 100644
index 0000000..bbbebef
--- /dev/null
+++ b/Htmt/ExpressionValidator.cs
@@ -0,0 +1,125 @@
+using System.Data;
+using System.Text.RegularExpressions;
+
+namespace Htmt;
+
+public class ExpressionValidator(string expression)
+{
+    public bool Validates(Dictionary<string, object?> data)
+    {
+        return EvaluateExp(Normalize(data));
+    }
+
+    private string Normalize(Dictionary<string, object?> data)
+    {
+        var evaluatedExpression = expression;
+        var keyMatches = Regex.Matches(expression, """'(?<string>[^']*)'|(?<key>\w+)""");
+        
+        foreach (Match match in keyMatches)
+        {
+            // if this is not a key, skip
+            if (match.Groups["key"].Success == false) continue;
+            
+            var key = match.Groups["key"].Value;
+            
+            // skip if the key is an operator
+            if (key is "is" or "and" or "or" or "not") continue;
+            
+            // skip if key is integer, double, float, boolean, null or string
+            if (int.TryParse(key, out _)) continue;
+            if (double.TryParse(key, out _)) continue;
+            if (float.TryParse(key, out _)) continue;
+            if (bool.TryParse(key, out _)) continue;
+            if (key == "null") continue;
+            
+            var value = Helper.FindValueByKeys(data, key.Split('.'));
+            var regex = new Regex($@"{key}");
+            
+            // if value is bool, lowercase it
+            if (value is bool b)
+            {
+                evaluatedExpression = regex.Replace(evaluatedExpression, b.ToString().ToLower(), 1);
+                continue;
+            }
+
+            evaluatedExpression = regex.Replace(evaluatedExpression, value?.ToString() ?? "null", 1);
+        }
+        
+        // remove single quotes from string values
+        return Regex.Replace(evaluatedExpression, "'(.*?)'", "$1");
+    }
+    
+    private static bool EvaluateExp(string exp)
+    {
+        while (exp.Contains('('))
+        {
+            var openIndex = exp.LastIndexOf('(');
+            var closeIndex = exp.IndexOf(')', openIndex);
+
+            if (openIndex == -1 || closeIndex == -1)
+            {
+                throw new SyntaxErrorException("Invalid expression");
+            }
+            
+            var subExp = exp.Substring(openIndex + 1, closeIndex - openIndex - 1);
+            var subResult = EvaluateSimpleExp(subExp);
+            
+            exp = exp.Substring(0, openIndex) + subResult.ToString().ToLower() + exp.Substring(closeIndex + 1);
+        }
+
+        return EvaluateSimpleExp(exp);
+    }
+
+    private static bool EvaluateSimpleExp(string exp)
+    {
+        var conditionParts = exp.Split(new[] { " is " }, StringSplitOptions.None);
+
+        if (conditionParts.Length > 1)
+        {
+            return EvaluateCondition(exp.Trim());
+        }
+        
+        var orParts = exp.Split(new[] { " or " }, StringSplitOptions.None);
+
+        foreach (var orPart in orParts)
+        {
+            var andParts = orPart.Split([" and "], StringSplitOptions.None);
+            var andResult = true;
+
+            foreach (var andPart in andParts)
+            {
+                andResult &= EvaluateCondition(andPart.Trim());
+            }
+            
+            if (andResult) return true;
+        }
+        
+        return false;
+    }
+
+    private static bool EvaluateCondition(string condition)
+    {
+        if (condition == "true") return true;
+        if (condition == "false") return false;
+        
+        if (condition.Contains(" is "))
+        {
+            var parts = condition.Split([" is "], StringSplitOptions.None);
+            var key = parts[0].Trim();
+            var value = parts[1].Trim();
+            
+            return key == value;
+        }
+        
+        if (condition.Contains(" not "))
+        {
+            var parts = condition.Split([" not "], StringSplitOptions.None);
+            var key = parts[0].Trim();
+            var value = parts[1].Trim();
+            
+            return key != value;
+        }
+        
+        throw new SyntaxErrorException("Invalid condition");
+    }
+}
\ No newline at end of file
diff --git a/Htmt/Helper.cs b/Htmt/Helper.cs
index 9e8a9ce..166a234 100644
--- a/Htmt/Helper.cs
+++ b/Htmt/Helper.cs
@@ -6,7 +6,7 @@ namespace Htmt;
 
 public partial class Helper
 {
-    public static object? FindValueByKeys(Dictionary<string, object> data, string[] keys)
+    public static object? FindValueByKeys(Dictionary<string, object?> data, string[] keys)
     {
         while (true)
         {
@@ -64,7 +64,7 @@ public partial class Helper
     [GeneratedRegex(@"(?<name>\{.*?\})")]
     private static partial Regex WholeKeyRegex();
     
-    public static string ReplaceKeysWithData(string str, Dictionary<string, object> data)
+    public static string ReplaceKeysWithData(string str, Dictionary<string, object?> data)
     {
         var matches = WholeKeyRegex().Matches(str).Select(x => x.Groups["name"].Value).ToArray();
         
diff --git a/Htmt/IAttributeParser.cs b/Htmt/IAttributeParser.cs
index 47cade1..400ce1a 100644
--- a/Htmt/IAttributeParser.cs
+++ b/Htmt/IAttributeParser.cs
@@ -6,5 +6,5 @@ public interface IAttributeParser
 {
     public string XTag { get; }
     
-    public void Parse(XmlDocument xml, Dictionary<string, object> data, XmlNodeList? nodes);
+    public void Parse(XmlDocument xml, Dictionary<string, object?> data, XmlNodeList? nodes);
 }
\ No newline at end of file
diff --git a/Htmt/Parser.cs b/Htmt/Parser.cs
index 00df9fa..ff31218 100644
--- a/Htmt/Parser.cs
+++ b/Htmt/Parser.cs
@@ -10,7 +10,7 @@ public class Parser
 
     public string Template { get; init; } = string.Empty;
 
-    public Dictionary<string, object> Data { get; init; } = new();
+    public Dictionary<string, object?> Data { get; init; } = new();
 
     public IAttributeParser[] AttributeParsers { get; init; } = [];
     
@@ -120,7 +120,7 @@ private void RunAttributeParsers()
         foreach(var parser in parsers)
         {
             var nodes = Xml.DocumentElement?.SelectNodes(parser.XTag, _nsManager);
-            var clonedData = new Dictionary<string, object>(Data);
+            var clonedData = new Dictionary<string, object?>(Data);
             parser.Parse(Xml, clonedData, nodes);
         }
         
diff --git a/HtmtTests/AttributeParserTest.cs b/HtmtTests/AttributeParserTest.cs
index ebec669..24f63a4 100644
--- a/HtmtTests/AttributeParserTest.cs
+++ b/HtmtTests/AttributeParserTest.cs
@@ -160,13 +160,24 @@ public void TestIfDictionaryAttributeParser()
     public void TestIfEmptyDictionaryAttributeParser()
     {
         const string template = "<html><body><p x:if=\"items\">There are items!</p></body></html>";
-        var data = new Dictionary<string, object> { { "items", new Dictionary<string, string>() } };
+        var data = new Dictionary<string, object?> { { "items", new Dictionary<string, string>() } };
         var parser = new Parser { Template = template, Data = data };
         var html = parser.ToHtml();
 
         Assert.AreEqual("<html><body></body></html>", html);
     }
 
+    [TestMethod]
+    public void TestComplexExpressionIfAttributeParser()
+    {
+        const string template = "<html><body><h1 x:if=\"(show is true) and (title is 'Hello, World!')\" x:inner-text=\"{title}\"></h1></body></html>";
+        var data = new Dictionary<string, object?> { { "show", true }, { "title", "Hello, World!" } };
+        var parser = new Parser { Template = template, Data = data };
+        var html = parser.ToHtml();
+        
+        Assert.AreEqual("<html><body><h1>Hello, World!</h1></body></html>", html);
+    }
+
     [TestMethod]
     public void TestUnlessAttributeParser()
     {
@@ -260,6 +271,17 @@ public void TestUnlessEmptyDictionaryAttributeParser()
 
         Assert.AreEqual("<html><body><p>There are no items!</p></body></html>", html);
     }
+    
+    [TestMethod]
+    public void TestComplexExpressionUnlessAttributeParser()
+    {
+        const string template = "<html><body><h1 x:unless=\"((show is true) and (title is 'Hello, World!')) is true\" x:inner-text=\"{title}\"></h1></body></html>";
+        var data = new Dictionary<string, object?> { { "show", true }, { "title", "Hello, World!" } };
+        var parser = new Parser { Template = template, Data = data };
+        var html = parser.ToHtml();
+        
+        Assert.AreEqual("<html><body></body></html>", html);
+    }
 
     [TestMethod]
     public void TestForAttributeParser()
diff --git a/HtmtTests/ExpressionValidatorTest.cs b/HtmtTests/ExpressionValidatorTest.cs
new file mode 100644
index 0000000..973edf9
--- /dev/null
+++ b/HtmtTests/ExpressionValidatorTest.cs
@@ -0,0 +1,127 @@
+using Htmt;
+
+namespace HtmtTests;
+
+[TestClass]
+public class ExpressionValidatorTest
+{
+    [TestMethod]
+    public void TestSimpleOr()
+    {
+        var returnsTrue = new ExpressionValidator("(1 is 1) or (2 is 3)").Validates(new Dictionary<string, object?>());
+        var returnsFalse = new ExpressionValidator("(1 is 2) or (2 is 3)").Validates(new Dictionary<string, object?>());
+        
+        Assert.IsTrue(returnsTrue);
+        Assert.IsFalse(returnsFalse);
+    }
+
+    [TestMethod]
+    public void TestIntComparisons()
+    {
+        var returnsTrue = new ExpressionValidator("test is 1").Validates(new Dictionary<string, object?>() { { "test", 1 } });
+        var returnsFalse = new ExpressionValidator("test is 1").Validates(new Dictionary<string, object?>() { { "test", 2 } });
+        
+        Assert.IsTrue(returnsTrue);
+        Assert.IsFalse(returnsFalse);
+    }
+    
+    [TestMethod]
+    public void TestDoubleComparisons()
+    {
+        var returnsTrue = new ExpressionValidator("test is 1.1").Validates(new Dictionary<string, object?>() { { "test", 1.1 } });
+        var returnsFalse = new ExpressionValidator("test is 1.1").Validates(new Dictionary<string, object?>() { { "test", 1.2 } });
+        
+        Assert.IsTrue(returnsTrue);
+        Assert.IsFalse(returnsFalse);
+    }
+    
+    [TestMethod]
+    public void TestFloatComparisons()
+    {
+        var returnsTrue = new ExpressionValidator("test is 1.1").Validates(new Dictionary<string, object?>() { { "test", 1.1f } });
+        var returnsFalse = new ExpressionValidator("test is 1.1").Validates(new Dictionary<string, object?>() { { "test", 1.2f } });
+        
+        Assert.IsTrue(returnsTrue);
+        Assert.IsFalse(returnsFalse);
+    }
+    
+    [TestMethod]
+    public void TestStringComparisons()
+    {
+        var returnsTrue = new ExpressionValidator("test is 'test'").Validates(new Dictionary<string, object>() { { "test", "test" } });
+        var returnsFalse = new ExpressionValidator("test is 'test'").Validates(new Dictionary<string, object?>() { { "test", "test2" } });
+        
+        Assert.IsTrue(returnsTrue);
+        Assert.IsFalse(returnsFalse);
+    }
+    
+    [TestMethod]
+    public void TestBooleanComparisons()
+    {
+        var returnsTrue = new ExpressionValidator("test is true").Validates(new Dictionary<string, object?>() { { "test", true } });
+        var returnsFalse = new ExpressionValidator("test is true").Validates(new Dictionary<string, object?>() { { "test", false } });
+        
+        Assert.IsTrue(returnsTrue);
+        Assert.IsFalse(returnsFalse);
+    }
+    
+    [TestMethod]
+    public void TestNullComparisons()
+    {
+        var returnsTrue = new ExpressionValidator("test is null").Validates(new Dictionary<string, object?>() { { "test", null } });
+        var returnsFalse = new ExpressionValidator("test is null").Validates(new Dictionary<string, object?>() { { "test", "test" } });
+        
+        Assert.IsTrue(returnsTrue);
+        Assert.IsFalse(returnsFalse);
+    }
+    
+    [TestMethod]
+    public void TestAnd()
+    {
+        var returnsTrue = new ExpressionValidator("(test is 1) and (test2 is 2)").Validates(new Dictionary<string, object?>() { { "test", 1 }, { "test2", 2 } });
+        var returnsFalse = new ExpressionValidator("(test is 1) and (test2 is 2)").Validates(new Dictionary<string, object?>() { { "test", 1 }, { "test2", 3 } });
+        
+        Assert.IsTrue(returnsTrue);
+        Assert.IsFalse(returnsFalse);
+    }
+    
+    [TestMethod]
+    public void TestComplexAndExpression()
+    {
+        var returnsTrue = new ExpressionValidator("((test is 1) and (test2 is 2)) or (test3 is 3)").Validates(new Dictionary<string, object?>() { { "test", 1 }, { "test2", 2 }, { "test3", 3 } });
+        var returnsFalse = new ExpressionValidator("((test is 1) and (test2 is 2))").Validates(new Dictionary<string, object?>() { { "test", 1 }, { "test2", 3 } });
+        
+        Assert.IsTrue(returnsTrue);
+        Assert.IsFalse(returnsFalse);
+    }
+    
+    [TestMethod]
+    public void TestComplexOrExpression()
+    {
+        var returnsTrue = new ExpressionValidator("((test is 1) or (test2 is 2)) and (test3 is 3)").Validates(new Dictionary<string, object?>() { { "test", 1 }, { "test2", 3 }, { "test3", 3 } });
+        var returnsFalse = new ExpressionValidator("((test is 1) or (test2 is 2))").Validates(new Dictionary<string, object?>() { { "test", 3 }, { "test2", 3 } });
+        
+        Assert.IsTrue(returnsTrue);
+        Assert.IsFalse(returnsFalse);
+    }
+    
+    [TestMethod]
+    public void TestComplexExpression()
+    {
+        var returnsTrue = new ExpressionValidator("((test is 1) or (test2 is 2)) and (test3 is 3)").Validates(new Dictionary<string, object?>() { { "test", 1 }, { "test2", 3 }, { "test3", 3 } });
+        var returnsFalse = new ExpressionValidator("((test is 1) or (test2 is 2))").Validates(new Dictionary<string, object?>() { { "test", 3 }, { "test2", 3 } });
+        
+        Assert.IsTrue(returnsTrue);
+        Assert.IsFalse(returnsFalse);
+    }
+
+    [TestMethod]
+    public void TestMultipleStringComparisons()
+    {
+        var returnsTrue = new ExpressionValidator("(test is 'test') and (test2 is 'test2')").Validates(new Dictionary<string, object?>() { { "test", "test" }, { "test2", "test2" } });
+        var returnsFalse = new ExpressionValidator("(test is 'test') and (test2 is 'test2')").Validates(new Dictionary<string, object?>() { { "test", "test" }, { "test2", "test3" } });
+        
+        Assert.IsTrue(returnsTrue);
+        Assert.IsFalse(returnsFalse);
+    }
+}
\ No newline at end of file
diff --git a/HtmtTests/HelperTest.cs b/HtmtTests/HelperTest.cs
index 75afc43..ca61412 100644
--- a/HtmtTests/HelperTest.cs
+++ b/HtmtTests/HelperTest.cs
@@ -8,7 +8,7 @@ public class HelperTest
     [TestMethod]
     public void TestReplaceKeysWithData()
     {
-        var data = new Dictionary<string, object> { { "name", "John Doe" } };
+        var data = new Dictionary<string, object?> { { "name", "John Doe" } };
         var result = Helper.ReplaceKeysWithData("Hello, {name}!", data);
         
         Assert.AreEqual("Hello, John Doe!", result);
@@ -17,7 +17,7 @@ public void TestReplaceKeysWithData()
     [TestMethod]
     public void TestReplaceKeysWithDataWithMultipleKeys()
     {
-        var data = new Dictionary<string, object> { { "name", "John Doe" }, { "age", 30 } };
+        var data = new Dictionary<string, object?> { { "name", "John Doe" }, { "age", 30 } };
         var result = Helper.ReplaceKeysWithData("Hello, {name}! You are {age} years old.", data);
         
         Assert.AreEqual("Hello, John Doe! You are 30 years old.", result);
@@ -26,7 +26,7 @@ public void TestReplaceKeysWithDataWithMultipleKeys()
     [TestMethod]
     public void TestReplaceKeysWithDataWithEmptyData()
     {
-        var result = Helper.ReplaceKeysWithData("Hello, {name}!", new Dictionary<string, object>());
+        var result = Helper.ReplaceKeysWithData("Hello, {name}!", new Dictionary<string, object?>());
 
         Assert.AreEqual("Hello, !", result);
     }

From 85d458ffc120770faeb519cd894289d13e37c707 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Asko=20N=C3=B5mm?= <asko@nth.ee>
Date: Thu, 17 Oct 2024 16:54:25 +0300
Subject: [PATCH 2/5] I think this is not needed at all.

---
 Htmt/ExpressionValidator.cs | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/Htmt/ExpressionValidator.cs b/Htmt/ExpressionValidator.cs
index bbbebef..743adc2 100644
--- a/Htmt/ExpressionValidator.cs
+++ b/Htmt/ExpressionValidator.cs
@@ -72,13 +72,6 @@ private static bool EvaluateExp(string exp)
 
     private static bool EvaluateSimpleExp(string exp)
     {
-        var conditionParts = exp.Split(new[] { " is " }, StringSplitOptions.None);
-
-        if (conditionParts.Length > 1)
-        {
-            return EvaluateCondition(exp.Trim());
-        }
-        
         var orParts = exp.Split(new[] { " or " }, StringSplitOptions.None);
 
         foreach (var orPart in orParts)

From 751fa8dc4c92263ce328d5824fea54ca3a68efaf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Asko=20N=C3=B5mm?= <asko@nth.ee>
Date: Fri, 18 Oct 2024 00:54:07 +0300
Subject: [PATCH 3/5] Improvements

---
 Htmt/Helper.cs                       | 14 +++++++-------
 HtmtTests/ExpressionValidatorTest.cs |  2 +-
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/Htmt/Helper.cs b/Htmt/Helper.cs
index 166a234..6f9ce77 100644
--- a/Htmt/Helper.cs
+++ b/Htmt/Helper.cs
@@ -30,27 +30,27 @@ public partial class Helper
                     keys = newKeys;
                     continue;
                 }
-                case Dictionary<string, string> dict:
+                case Dictionary<string, string?> dict:
                 {
                     var newKeys = keys.Skip(1).ToArray();
 
-                    data = dict.ToDictionary(x => x.Key, x => (object)x.Value);
+                    data = dict.ToDictionary(x => x.Key, object? (x) => x.Value);
                     keys = newKeys;
                     continue;
                 }
-                case Dictionary<string, int> dict:
+                case Dictionary<string, int?> dict:
                 {
                     var newKeys = keys.Skip(1).ToArray();
 
-                    data = dict.ToDictionary(x => x.Key, x => (object)x.Value);
+                    data = dict.ToDictionary(x => x.Key, x => (object?) x.Value);
                     keys = newKeys;
                     continue;
                 }
-                case Dictionary<string, bool> dict:
+                case Dictionary<string, bool?> dict:
                 {
                     var newKeys = keys.Skip(1).ToArray();
-
-                    data = dict.ToDictionary(x => x.Key, x => (object)x.Value);
+                    
+                    data = dict.ToDictionary(x => x.Key, x => (object?) x.Value);
                     keys = newKeys;
                     continue;
                 }
diff --git a/HtmtTests/ExpressionValidatorTest.cs b/HtmtTests/ExpressionValidatorTest.cs
index 973edf9..e65d157 100644
--- a/HtmtTests/ExpressionValidatorTest.cs
+++ b/HtmtTests/ExpressionValidatorTest.cs
@@ -48,7 +48,7 @@ public void TestFloatComparisons()
     [TestMethod]
     public void TestStringComparisons()
     {
-        var returnsTrue = new ExpressionValidator("test is 'test'").Validates(new Dictionary<string, object>() { { "test", "test" } });
+        var returnsTrue = new ExpressionValidator("test is 'test'").Validates(new Dictionary<string, object?>() { { "test", "test" } });
         var returnsFalse = new ExpressionValidator("test is 'test'").Validates(new Dictionary<string, object?>() { { "test", "test2" } });
         
         Assert.IsTrue(returnsTrue);

From 105d218c1d1d78bfd926ff163fd788f6a6025118 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Asko=20N=C3=B5mm?= <asko@nth.ee>
Date: Fri, 18 Oct 2024 01:45:04 +0300
Subject: [PATCH 4/5] More improvements

---
 HtmtTests/AttributeParserTest.cs | 41 +++++++++++++++-----------------
 HtmtTests/ParserTest.cs          |  6 ++---
 2 files changed, 22 insertions(+), 25 deletions(-)

diff --git a/HtmtTests/AttributeParserTest.cs b/HtmtTests/AttributeParserTest.cs
index 24f63a4..c3bf8fd 100644
--- a/HtmtTests/AttributeParserTest.cs
+++ b/HtmtTests/AttributeParserTest.cs
@@ -9,8 +9,7 @@ public class AttributeParserTest
     public void TestGenericValueAttributeParser()
     {
         const string template = "<html><body><a x:href=\"{url}\" x:title=\"Hello {name}\">Click here</a></body></html>";
-        var data = new Dictionary<string, object>
-            { { "url", "https://www.example.com" }, { "name", "Example Website" } };
+        var data = new Dictionary<string, object?> { { "url", "https://www.example.com" }, { "name", "Example Website" } };
         var parser = new Parser { Template = template, Data = data };
         var html = parser.ToHtml();
 
@@ -33,7 +32,7 @@ public void TestGenericValueAttributeParserWithouData()
     public void TestInnerTextAttributeParser()
     {
         const string template = "<html><body><h1 x:inner-text=\"{title}\"></h1></body></html>";
-        var data = new Dictionary<string, object> { { "title", "Hello, World!" } };
+        var data = new Dictionary<string, object?> { { "title", "Hello, World!" } };
         var parser = new Parser { Template = template, Data = data };
         var html = parser.ToHtml();
 
@@ -44,7 +43,7 @@ public void TestInnerTextAttributeParser()
     public void TestInnerHtmlAttributeParser()
     {
         const string template = "<html><body><div x:inner-html=\"{content}\"></div></body></html>";
-        var data = new Dictionary<string, object> { { "content", "<h1>Hello, World!</h1>" } };
+        var data = new Dictionary<string, object?> { { "content", "<h1>Hello, World!</h1>" } };
         var parser = new Parser { Template = template, Data = data };
         var html = parser.ToHtml();
 
@@ -55,7 +54,7 @@ public void TestInnerHtmlAttributeParser()
     public void TestOuterTextAttributeParser()
     {
         const string template = "<html><body><h1 x:outer-text=\"{title}\"></h1></body></html>";
-        var data = new Dictionary<string, object> { { "title", "Hello, World!" } };
+        var data = new Dictionary<string, object?> { { "title", "Hello, World!" } };
         var parser = new Parser { Template = template, Data = data };
         var html = parser.ToHtml();
 
@@ -66,7 +65,7 @@ public void TestOuterTextAttributeParser()
     public void TestOuterHtmlAttributeParser()
     {
         const string template = "<html><body><div x:outer-html=\"{content}\"></div></body></html>";
-        var data = new Dictionary<string, object> { { "content", "<h1>Hello, World!</h1>" } };
+        var data = new Dictionary<string, object?> { { "content", "<h1>Hello, World!</h1>" } };
         var parser = new Parser { Template = template, Data = data };
         var html = parser.ToHtml();
 
@@ -77,7 +76,7 @@ public void TestOuterHtmlAttributeParser()
     public void TestIfAttributeParser()
     {
         const string template = "<html><body><h1 x:if=\"show\" x:inner-text=\"{title}\"></h1></body></html>";
-        var data = new Dictionary<string, object> { { "show", true }, { "title", "Hello, World!" } };
+        var data = new Dictionary<string, object?> { { "show", true }, { "title", "Hello, World!" } };
         var parser = new Parser { Template = template, Data = data };
         var html = parser.ToHtml();
 
@@ -88,7 +87,7 @@ public void TestIfAttributeParser()
     public void TestIfNotAttributeParser()
     {
         const string template = "<html><body><h1 x:if=\"show\" x:inner-text=\"{title}\"></h1></body></html>";
-        var data = new Dictionary<string, object> { { "show", false }, { "title", "Hello, World!" } };
+        var data = new Dictionary<string, object?> { { "show", false }, { "title", "Hello, World!" } };
         var parser = new Parser { Template = template, Data = data };
         var html = parser.ToHtml();
 
@@ -109,7 +108,7 @@ public void TestIfNoDataAttributeParser()
     public void TestIfListAttributeParser()
     {
         const string template = "<html><body><p x:if=\"items\">There are items!</p></body></html>";
-        var data = new Dictionary<string, object> { { "items", new List<string> { "Item 1", "Item 2", "Item 3" } } };
+        var data = new Dictionary<string, object?> { { "items", new List<string> { "Item 1", "Item 2", "Item 3" } } };
         var parser = new Parser { Template = template, Data = data };
         var html = parser.ToHtml();
 
@@ -120,7 +119,7 @@ public void TestIfListAttributeParser()
     public void TestIfListOfDictsAttributeParser()
     {
         const string template = "<html><body><p x:if=\"items\">There are items!</p></body></html>";
-        var data = new Dictionary<string, object>
+        var data = new Dictionary<string, object?>
         {
             {
                 "items",
@@ -137,7 +136,7 @@ public void TestIfListOfDictsAttributeParser()
     public void TestIfEmptyListAttributeParser()
     {
         const string template = "<html><body><p x:if=\"items\">There are items!</p></body></html>";
-        var data = new Dictionary<string, object> { { "items", new List<string>() } };
+        var data = new Dictionary<string, object?> { { "items", new List<string>() } };
         var parser = new Parser { Template = template, Data = data };
         var html = parser.ToHtml();
 
@@ -148,8 +147,7 @@ public void TestIfEmptyListAttributeParser()
     public void TestIfDictionaryAttributeParser()
     {
         const string template = "<html><body><p x:if=\"items\">There are items!</p></body></html>";
-        var data = new Dictionary<string, object>
-            { { "items", new Dictionary<string, string> { { "key1", "Item 1" }, { "key2", "Item 2" } } } };
+        var data = new Dictionary<string, object?> { { "items", new Dictionary<string, string> { { "key1", "Item 1" }, { "key2", "Item 2" } } } };
         var parser = new Parser { Template = template, Data = data };
         var html = parser.ToHtml();
 
@@ -182,7 +180,7 @@ public void TestComplexExpressionIfAttributeParser()
     public void TestUnlessAttributeParser()
     {
         const string template = "<html><body><h1 x:unless=\"show\" x:inner-text=\"{title}\"></h1></body></html>";
-        var data = new Dictionary<string, object> { { "show", false }, { "title", "Hello, World!" } };
+        var data = new Dictionary<string, object?> { { "show", false }, { "title", "Hello, World!" } };
         var parser = new Parser { Template = template, Data = data };
         var html = parser.ToHtml();
 
@@ -193,7 +191,7 @@ public void TestUnlessAttributeParser()
     public void TestUnlessNotAttributeParser()
     {
         const string template = "<html><body><h1 x:unless=\"show\" x:inner-text=\"{title}\"></h1></body></html>";
-        var data = new Dictionary<string, object> { { "show", true }, { "title", "Hello, World!" } };
+        var data = new Dictionary<string, object?> { { "show", true }, { "title", "Hello, World!" } };
         var parser = new Parser { Template = template, Data = data };
         var html = parser.ToHtml();
 
@@ -214,7 +212,7 @@ public void TestUnlessNoDataAttributeParser()
     public void TestUnlessListAttributeParser()
     {
         const string template = "<html><body><p x:unless=\"items\">There are no items!</p></body></html>";
-        var data = new Dictionary<string, object> { { "items", new List<string> { "Item 1", "Item 2", "Item 3" } } };
+        var data = new Dictionary<string, object?> { { "items", new List<string> { "Item 1", "Item 2", "Item 3" } } };
         var parser = new Parser { Template = template, Data = data };
         var html = parser.ToHtml();
 
@@ -225,7 +223,7 @@ public void TestUnlessListAttributeParser()
     public void TestUnlessListOfDictsAttributeParser()
     {
         const string template = "<html><body><p x:unless=\"items\">There are no items!</p></body></html>";
-        var data = new Dictionary<string, object>
+        var data = new Dictionary<string, object?>
         {
             {
                 "items",
@@ -242,7 +240,7 @@ public void TestUnlessListOfDictsAttributeParser()
     public void TestUnlessEmptyListAttributeParser()
     {
         const string template = "<html><body><p x:unless=\"items\">There are no items!</p></body></html>";
-        var data = new Dictionary<string, object> { { "items", new List<string>() } };
+        var data = new Dictionary<string, object?> { { "items", new List<string>() } };
         var parser = new Parser { Template = template, Data = data };
         var html = parser.ToHtml();
 
@@ -253,8 +251,7 @@ public void TestUnlessEmptyListAttributeParser()
     public void TestUnlessDictionaryAttributeParser()
     {
         const string template = "<html><body><p x:unless=\"items\">There are no items!</p></body></html>";
-        var data = new Dictionary<string, object>
-            { { "items", new Dictionary<string, string> { { "key1", "Item 1" }, { "key2", "Item 2" } } } };
+        var data = new Dictionary<string, object?> { { "items", new Dictionary<string, string> { { "key1", "Item 1" }, { "key2", "Item 2" } } } };
         var parser = new Parser { Template = template, Data = data };
         var html = parser.ToHtml();
 
@@ -265,7 +262,7 @@ public void TestUnlessDictionaryAttributeParser()
     public void TestUnlessEmptyDictionaryAttributeParser()
     {
         const string template = "<html><body><p x:unless=\"items\">There are no items!</p></body></html>";
-        var data = new Dictionary<string, object> { { "items", new Dictionary<string, string>() } };
+        var data = new Dictionary<string, object?> { { "items", new Dictionary<string, string>() } };
         var parser = new Parser { Template = template, Data = data };
         var html = parser.ToHtml();
 
@@ -288,7 +285,7 @@ public void TestForAttributeParser()
     {
         const string template =
             "<html><body><ul><li x:for=\"items\" x:as=\"item\"><span x:outer-text=\"{item}\" /></li></ul></body></html>";
-        var data = new Dictionary<string, object> { { "items", new List<string> { "Item 1", "Item 2", "Item 3" } } };
+        var data = new Dictionary<string, object?> { { "items", new List<string> { "Item 1", "Item 2", "Item 3" } } };
         var parser = new Parser { Template = template, Data = data };
         var html = parser.ToHtml();
 
diff --git a/HtmtTests/ParserTest.cs b/HtmtTests/ParserTest.cs
index 0908df6..010b0aa 100644
--- a/HtmtTests/ParserTest.cs
+++ b/HtmtTests/ParserTest.cs
@@ -9,7 +9,7 @@ public class ParserTest
     public void TestHtml5Document()
     {
         const string template = "<!DOCTYPE html><html><head><title x:inner-text=\"{title}\"></title></head><body><h1 x:inner-text=\"{heading}\"></h1></body></html>";
-        var data = new Dictionary<string, object> { { "title", "Hello, World!" }, { "heading", "Welcome to the world!" } };
+        var data = new Dictionary<string, object?> { { "title", "Hello, World!" }, { "heading", "Welcome to the world!" } };
         var parser = new Htmt.Parser { Template = template, Data = data };
         var html = parser.ToHtml();
         
@@ -20,7 +20,7 @@ public void TestHtml5Document()
     public void TestHtml5DocumentWithComments()
     {
         const string template = "<!DOCTYPE html><!-- This is a comment --><html><head><title x:inner-text=\"{title}\"></title></head><body><h1 x:inner-text=\"{heading}\"></h1></body></html>";
-        var data = new Dictionary<string, object> { { "title", "Hello, World!" }, { "heading", "Welcome to the world!" } };
+        var data = new Dictionary<string, object?> { { "title", "Hello, World!" }, { "heading", "Welcome to the world!" } };
         var parser = new Htmt.Parser { Template = template, Data = data };
         var html = parser.ToHtml();
         
@@ -31,7 +31,7 @@ public void TestHtml5DocumentWithComments()
     public void TestHtml4Document()
     {
         const string template = "<!DOCTYPE html PUBLIC \"-//W3C//DTD HTML 4.01//EN\" \"http://www.w3.org/TR/html4/strict.dtd\"><html><head><title x:inner-text=\"{title}\"></title></head><body><h1 x:inner-text=\"{heading}\"></h1></body></html>";
-        var data = new Dictionary<string, object> { { "title", "Hello, World!" }, { "heading", "Welcome to the world!" } };
+        var data = new Dictionary<string, object?> { { "title", "Hello, World!" }, { "heading", "Welcome to the world!" } };
         var parser = new Htmt.Parser { Template = template, Data = data };
         var html = parser.ToHtml();
         

From 16dcc67469dce84e49ed07e2ffb5a48ecd2ba11e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Asko=20N=C3=B5mm?= <asko@nth.ee>
Date: Fri, 18 Oct 2024 01:55:40 +0300
Subject: [PATCH 5/5] And even more

---
 Htmt/Helper.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Htmt/Helper.cs b/Htmt/Helper.cs
index 6f9ce77..479b6c3 100644
--- a/Htmt/Helper.cs
+++ b/Htmt/Helper.cs
@@ -22,7 +22,7 @@ public partial class Helper
 
             switch (v)
             {
-                case Dictionary<string, object> dict:
+                case Dictionary<string, object?> dict:
                 {
                     var newKeys = keys.Skip(1).ToArray();