...

compiler/Compiler/Parser.cs

@@ -70,6 +70,16 @@ public sealed class Parser(List<Token> tokens)
             return new NodeStatementReturn(TokensFrom(startIndex), value);
         }
 
+        if (TryExpectKeyword(Keyword.Let))
+        {
+            var name = ExpectIdent();
+            ExpectSymbol(Symbol.Colon);
+            var type = ParseType();
+            ExpectSymbol(Symbol.Equal);
+            var value = ParseExpression();
+            return new NodeStatementVariableDeclaration(TokensFrom(startIndex), name, type, value);
+        }
+
         var expression = ParseExpression();
         var parameters = new List<NodeExpression>();
 
@@ -324,6 +334,13 @@ internal class NodeStatementReturn(List<Token> tokens, NodeExpression value) : N
     public readonly NodeExpression Value = value;
 }
 
+internal class NodeStatementVariableDeclaration(List<Token> tokens, TokenIdent name, NodeType type, NodeExpression value) : NodeStatement(tokens)
+{
+    public readonly TokenIdent Name = name;
+    public readonly NodeType Type = type;
+    public readonly NodeExpression Value = value;
+}
+
 public abstract class NodeExpression(List<Token> tokens) : Node(tokens);
 
 public sealed class NodeExpressionIntLiteral(List<Token> tokens, TokenIntLiteral value) : NodeExpression(tokens)