Implement expression validator.

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))
                 {

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)

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);
+                }
             }
         }
     }

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)

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)

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)

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)

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);
+                }
             }
         }
     }

Htmt/ExpressionValidator.cs

@@ -0,0 +1,118 @@
+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 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");
+    }
+}

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)
         {
@@ -22,35 +22,35 @@ public partial class Helper
 
             switch (v)
             {
-                case Dictionary<string, object> dict:
+                case Dictionary<string, object?> dict:
                 {
                     var newKeys = keys.Skip(1).ToArray();
 
                     data = dict;
                     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;
                 }
@@ -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();
 

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);
 }