...

compiler/Compiler/Parser.cs

@@ -80,6 +80,18 @@ public sealed class Parser(List<Token> tokens)
             return new NodeStatementVariableDeclaration(TokensFrom(startIndex), name, type, value);
         }
 
+        if (TryExpectKeyword(Keyword.If))
+        {
+            var condition = ParseExpression();
+            var thenBlock = ParseStatement();
+            NodeStatement? elseBlock = null;
+
+            if (TryExpectKeyword(Keyword.Else))
+                elseBlock = ParseStatement();
+
+            return new NodeStatementIf(TokensFrom(startIndex), condition, thenBlock, elseBlock);
+        }
+
         var target = ParseExpression();
 
         if (TryExpectSymbol(Symbol.OpenParen))
@@ -308,7 +320,7 @@ public sealed class Parser(List<Token> tokens)
 
 public abstract class Node(List<Token> tokens)
 {
-    public List<Token> Tokens = tokens;
+    public readonly List<Token> Tokens = tokens;
 }
 
 public abstract class NodeDefinition(List<Token> tokens) : Node(tokens);
@@ -358,6 +370,13 @@ internal class NodeStatementAssignment(List<Token> tokens, NodeExpression target
     public readonly NodeExpression Value = value;
 }
 
+internal class NodeStatementIf(List<Token> tokens, NodeExpression condition, NodeStatement thenBlock, NodeStatement? elseBlock) : NodeStatement(tokens)
+{
+    public readonly NodeExpression Condition = condition;
+    public readonly NodeStatement ThenBlock = thenBlock;
+    public readonly NodeStatement? ElseBlock = elseBlock;
+}
+
 public abstract class NodeExpression(List<Token> tokens) : Node(tokens);
 
 public sealed class NodeExpressionIntLiteral(List<Token> tokens, TokenIntLiteral value) : NodeExpression(tokens)