...

.vscode/settings.json

@@ -0,0 +1,5 @@
+{
+    "files.associations": {
+        "ref.h": "c"
+    }
+}

compiler/NubLang.CLI/Program.cs

@@ -21,7 +21,7 @@ foreach (var file in args)
 }
 
 var modules = Module.Collect(syntaxTrees);
-var compilationUnits = new List<CompilationUnit>();
+var compilationUnits = new List<List<TopLevelNode>>();
 
 for (var i = 0; i < args.Length; i++)
 {
@@ -46,6 +46,43 @@ var cPaths = new List<string>();
 
 Directory.CreateDirectory(".build");
 
+var typedModules = modules.Select(x => (x.Key, TypedModule.FromModule(x.Key, x.Value, modules))).ToDictionary();
+
+var moduleHeaders = new List<string>();
+
+var commonHeaderOut = Path.Combine(".build", "runtime.h");
+
+File.WriteAllText(commonHeaderOut, """
+                                   #include <stddef.h>
+
+                                   void *rc_alloc(size_t size, void (*destructor)(void *self));
+                                   void rc_retain(void *obj);
+                                   void rc_release(void *obj);
+
+                                   typedef struct
+                                   {
+                                       unsigned long long length;
+                                       char *data;
+                                   } nub_string;
+
+                                   typedef struct
+                                   {
+                                       unsigned long long length;
+                                       void *data;
+                                   } nub_slice;
+                                   """);
+
+moduleHeaders.Add(commonHeaderOut);
+
+foreach (var typedModule in typedModules)
+{
+    var header = HeaderGenerator.Generate(typedModule.Key, typedModule.Value);
+    var headerOut = Path.Combine(".build", "modules", typedModule.Key + ".h");
+    Directory.CreateDirectory(Path.Combine(".build", "modules"));
+    File.WriteAllText(headerOut, header);
+    moduleHeaders.Add(headerOut);
+}
+
 for (var i = 0; i < args.Length; i++)
 {
     var file = args[i];
@@ -69,6 +106,7 @@ foreach (var cPath in cPaths)
 {
     var objectPath = Path.ChangeExtension(cPath, "o");
     using var compileProcess = Process.Start("clang", [
+        ..moduleHeaders.SelectMany(x => new[] { "-include", x }),
         "-ffreestanding", "-std=c23",
         "-g", "-c",
         "-o", objectPath,

compiler/NubLang.LSP/AstExtensions.cs

@@ -1,5 +1,4 @@
 using NubLang.Ast;
-using NubLang.Syntax;
 using OmniSharp.Extensions.LanguageServer.Protocol.Models;
 using Range = OmniSharp.Extensions.LanguageServer.Protocol.Models.Range;
 
@@ -58,16 +57,16 @@ public static class AstExtensions
         return false;
     }
 
-    public static FuncNode? FunctionAtPosition(this CompilationUnit compilationUnit, int line, int character)
+    public static FuncNode? FunctionAtPosition(this List<TopLevelNode> compilationUnit, int line, int character)
     {
         return compilationUnit
-            .Functions
+            .OfType<FuncNode>()
             .FirstOrDefault(x => x.ContainsPosition(line, character));
     }
 
-    public static Node? DeepestNodeAtPosition(this CompilationUnit compilationUnit, int line, int character)
+    public static Node? DeepestNodeAtPosition(this List<TopLevelNode> compilationUnit, int line, int character)
     {
-        return compilationUnit.Functions
+        return compilationUnit
             .SelectMany(x => x.DescendantsAndSelf())
             .Where(n => n.ContainsPosition(line, character))
             .OrderBy(n => n.Tokens.First().Span.Start.Line)

compiler/NubLang.LSP/CompletionHandler.cs

@@ -118,35 +118,38 @@ internal class CompletionHandler(WorkspaceManager workspaceManager) : Completion
         var compilationUnit = workspaceManager.GetCompilationUnit(uri);
         if (compilationUnit != null)
         {
-            var function = compilationUnit.Functions.FirstOrDefault(x => x.Body != null && x.Body.ContainsPosition(position.Line, position.Character));
+            var function = compilationUnit.OfType<FuncNode>().FirstOrDefault(x => x.Body != null && x.Body.ContainsPosition(position.Line, position.Character));
             if (function != null)
             {
                 completions.AddRange(_statementSnippets);
 
-                foreach (var prototype in compilationUnit.ImportedFunctions)
-                {
-                    var parameterStrings = new List<string>();
-                    foreach (var (index, parameter) in prototype.Parameters.Index())
-                    {
-                        parameterStrings.AddRange($"${{{index + 1}:{parameter.Name}}}");
-                    }
-
-                    completions.Add(new CompletionItem
-                    {
-                        Kind = CompletionItemKind.Function,
-                        Label = $"{prototype.Module}::{prototype.Name}",
-                        InsertTextFormat = InsertTextFormat.Snippet,
-                        InsertText = $"{prototype.Module}::{prototype.Name}({string.Join(", ", parameterStrings)})",
-                    });
-                }
+                // foreach (var (module, prototypes) in compilationUnit.ImportedFunctions)
+                // {
+                //     foreach (var prototype in prototypes)
+                //     {
+                //         var parameterStrings = new List<string>();
+                //         foreach (var (index, parameter) in prototype.Parameters.Index())
+                //         {
+                //             parameterStrings.AddRange($"${{{index + 1}:{parameter.NameToken.Value}}}");
+                //         }
+                //
+                //         completions.Add(new CompletionItem
+                //         {
+                //             Kind = CompletionItemKind.Function,
+                //             Label = $"{module.Value}::{prototype.NameToken.Value}",
+                //             InsertTextFormat = InsertTextFormat.Snippet,
+                //             InsertText = $"{module.Value}::{prototype.NameToken.Value}({string.Join(", ", parameterStrings)})",
+                //         });
+                //     }
+                // }
 
                 foreach (var parameter in function.Prototype.Parameters)
                 {
                     completions.Add(new CompletionItem
                     {
                         Kind = CompletionItemKind.Variable,
-                        Label = parameter.Name,
-                        InsertText = parameter.Name,
+                        Label = parameter.NameToken.Value,
+                        InsertText = parameter.NameToken.Value,
                     });
                 }
 
@@ -159,8 +162,8 @@ internal class CompletionHandler(WorkspaceManager workspaceManager) : Completion
                     completions.Add(new CompletionItem
                     {
                         Kind = CompletionItemKind.Variable,
-                        Label = variable.Name,
-                        InsertText = variable.Name,
+                        Label = variable.NameToken.Value,
+                        InsertText = variable.NameToken.Value,
                     });
                 }
             }

compiler/NubLang.LSP/DefinitionHandler.cs

@@ -37,7 +37,7 @@ internal class DefinitionHandler(WorkspaceManager workspaceManager) : Definition
             {
                 var function = compilationUnit.FunctionAtPosition(line, character);
 
-                var parameter = function?.Prototype.Parameters.FirstOrDefault(x => x.Name == variableIdentifierNode.Name);
+                var parameter = function?.Prototype.Parameters.FirstOrDefault(x => x.NameToken.Value == variableIdentifierNode.NameToken.Value);
                 if (parameter != null)
                 {
                     return new LocationOrLocationLinks(parameter.ToLocation());
@@ -46,7 +46,7 @@ internal class DefinitionHandler(WorkspaceManager workspaceManager) : Definition
                 var variable = function?.Body?
                     .Descendants()
                     .OfType<VariableDeclarationNode>()
-                    .FirstOrDefault(x => x.Name == variableIdentifierNode.Name);
+                    .FirstOrDefault(x => x.NameToken.Value == variableIdentifierNode.NameToken.Value);
 
                 if (variable != null)
                 {
@@ -57,11 +57,16 @@ internal class DefinitionHandler(WorkspaceManager workspaceManager) : Definition
             }
             case FuncIdentifierNode funcIdentifierNode:
             {
-                var prototype = compilationUnit.ImportedFunctions.FirstOrDefault(x => x.Module == funcIdentifierNode.Module && x.Name == funcIdentifierNode.Name);
-                if (prototype != null)
-                {
-                    return new LocationOrLocationLinks(prototype.ToLocation());
-                }
+                // var prototype = compilationUnit
+                //     .ImportedFunctions
+                //     .Where(x => x.Key.Value == funcIdentifierNode.ModuleToken.Value)
+                //     .SelectMany(x => x.Value)
+                //     .FirstOrDefault(x => x.NameToken.Value == funcIdentifierNode.NameToken.Value);
+                //
+                // if (prototype != null)
+                // {
+                //     return new LocationOrLocationLinks(prototype.ToLocation());
+                // }
 
                 return null;
             }

compiler/NubLang.LSP/HoverHandler.cs

@@ -39,104 +39,110 @@ internal class HoverHandler(WorkspaceManager workspaceManager) : HoverHandlerBas
             return null;
         }
 
-        var message = CreateMessage(hoveredNode, compilationUnit);
-        if (message == null)
-        {
-            return null;
-        }
+        // var message = CreateMessage(hoveredNode, compilationUnit);
+        // if (message == null)
+        // {
+        //     return null;
+        // }
+        //
+        // return new Hover
+        // {
+        //     Contents = new MarkedStringsOrMarkupContent(new MarkupContent
+        //     {
+        //         Value = message,
+        //         Kind = MarkupKind.Markdown,
+        //     })
+        // };
 
-        return new Hover
-        {
-            Contents = new MarkedStringsOrMarkupContent(new MarkupContent
-            {
-                Value = message,
-                Kind = MarkupKind.Markdown,
-            })
-        };
+        return null;
     }
 
-    private static string? CreateMessage(Node hoveredNode, CompilationUnit compilationUnit)
-    {
-        return hoveredNode switch
-        {
-            FuncNode funcNode => CreateFuncPrototypeMessage(funcNode.Prototype),
-            FuncPrototypeNode funcPrototypeNode => CreateFuncPrototypeMessage(funcPrototypeNode),
-            FuncIdentifierNode funcIdentifierNode => CreateFuncIdentifierMessage(funcIdentifierNode, compilationUnit),
-            FuncParameterNode funcParameterNode => CreateTypeNameMessage("Function parameter", funcParameterNode.Name, funcParameterNode.Type),
-            VariableIdentifierNode variableIdentifierNode => CreateTypeNameMessage("Variable", variableIdentifierNode.Name, variableIdentifierNode.Type),
-            VariableDeclarationNode variableDeclarationNode => CreateTypeNameMessage("Variable declaration", variableDeclarationNode.Name, variableDeclarationNode.Type),
-            StructFieldAccessNode structFieldAccessNode => CreateTypeNameMessage("Struct field", $"{structFieldAccessNode.Target.Type}.{structFieldAccessNode.Field}", structFieldAccessNode.Type),
-            CStringLiteralNode cStringLiteralNode => CreateLiteralMessage(cStringLiteralNode.Type, '"' + cStringLiteralNode.Value + '"'),
-            StringLiteralNode stringLiteralNode => CreateLiteralMessage(stringLiteralNode.Type, '"' + stringLiteralNode.Value + '"'),
-            BoolLiteralNode boolLiteralNode => CreateLiteralMessage(boolLiteralNode.Type, boolLiteralNode.Value.ToString()),
-            Float32LiteralNode float32LiteralNode => CreateLiteralMessage(float32LiteralNode.Type, float32LiteralNode.Value.ToString(CultureInfo.InvariantCulture)),
-            Float64LiteralNode float64LiteralNode => CreateLiteralMessage(float64LiteralNode.Type, float64LiteralNode.Value.ToString(CultureInfo.InvariantCulture)),
-            I8LiteralNode i8LiteralNode => CreateLiteralMessage(i8LiteralNode.Type, i8LiteralNode.Value.ToString()),
-            I16LiteralNode i16LiteralNode => CreateLiteralMessage(i16LiteralNode.Type, i16LiteralNode.Value.ToString()),
-            I32LiteralNode i32LiteralNode => CreateLiteralMessage(i32LiteralNode.Type, i32LiteralNode.Value.ToString()),
-            I64LiteralNode i64LiteralNode => CreateLiteralMessage(i64LiteralNode.Type, i64LiteralNode.Value.ToString()),
-            U8LiteralNode u8LiteralNode => CreateLiteralMessage(u8LiteralNode.Type, u8LiteralNode.Value.ToString()),
-            U16LiteralNode u16LiteralNode => CreateLiteralMessage(u16LiteralNode.Type, u16LiteralNode.Value.ToString()),
-            U32LiteralNode u32LiteralNode => CreateLiteralMessage(u32LiteralNode.Type, u32LiteralNode.Value.ToString()),
-            U64LiteralNode u64LiteralNode => CreateLiteralMessage(u64LiteralNode.Type, u64LiteralNode.Value.ToString()),
-            // Expressions can have a generic fallback showing the resulting type
-            ExpressionNode expressionNode => $"""
-                                              **Expression** `{expressionNode.GetType().Name}`
-                                              ```nub
-                                              {expressionNode.Type}
-                                              ```
-                                              """,
-            BlockNode => null,
-            _ => hoveredNode.GetType().Name
-        };
-    }
-
-    private static string CreateLiteralMessage(NubType type, string value)
-    {
-        return $"""
-                **Literal** `{type}`
-                ```nub
-                {value}: {type}
-                ```
-                """;
-    }
-
-    private static string CreateTypeNameMessage(string description, string name, NubType type)
-    {
-        return $"""
-                **{description}** `{name}`
-                ```nub
-                {name}: {type}
-                ```
-                """;
-    }
-
-    private static string CreateFuncIdentifierMessage(FuncIdentifierNode funcIdentifierNode, CompilationUnit compilationUnit)
-    {
-        var func = compilationUnit.ImportedFunctions.FirstOrDefault(x => x.Module == funcIdentifierNode.Module && x.Name == funcIdentifierNode.Name);
-        if (func == null)
-        {
-            return $"""
-                    **Function** `{funcIdentifierNode.Module}::{funcIdentifierNode.Name}`
-                    ```nub
-                    // Declaration not found
-                    ```
-                    """;
-        }
-
-        return CreateFuncPrototypeMessage(func);
-    }
-
-    private static string CreateFuncPrototypeMessage(FuncPrototypeNode funcPrototypeNode)
-    {
-        var parameterText = string.Join(", ", funcPrototypeNode.Parameters.Select(x => $"{x.Name}: {x.Type}"));
-        var externText = funcPrototypeNode.ExternSymbol != null ? $"extern \"{funcPrototypeNode.ExternSymbol}\" " : "";
-
-        return $"""
-                **Function** `{funcPrototypeNode.Module}::{funcPrototypeNode.Name}`
-                ```nub
-                {externText}func {funcPrototypeNode.Module}::{funcPrototypeNode.Name}({parameterText}): {funcPrototypeNode.ReturnType}
-                ```
-                """;
-    }
+//     private static string? CreateMessage(Node hoveredNode, CompilationUnit compilationUnit)
+//     {
+//         return hoveredNode switch
+//         {
+//             FuncNode funcNode => CreateFuncPrototypeMessage(funcNode.Prototype),
+//             FuncPrototypeNode funcPrototypeNode => CreateFuncPrototypeMessage(funcPrototypeNode),
+//             FuncIdentifierNode funcIdentifierNode => CreateFuncIdentifierMessage(funcIdentifierNode, compilationUnit),
+//             FuncParameterNode funcParameterNode => CreateTypeNameMessage("Function parameter", funcParameterNode.NameToken.Value, funcParameterNode.Type),
+//             VariableIdentifierNode variableIdentifierNode => CreateTypeNameMessage("Variable", variableIdentifierNode.NameToken.Value, variableIdentifierNode.Type),
+//             VariableDeclarationNode variableDeclarationNode => CreateTypeNameMessage("Variable declaration", variableDeclarationNode.NameToken.Value, variableDeclarationNode.Type),
+//             StructFieldAccessNode structFieldAccessNode => CreateTypeNameMessage("Struct field", $"{structFieldAccessNode.Target.Type}.{structFieldAccessNode.FieldToken.Value}", structFieldAccessNode.Type),
+//             CStringLiteralNode cStringLiteralNode => CreateLiteralMessage(cStringLiteralNode.Type, '"' + cStringLiteralNode.Value + '"'),
+//             StringLiteralNode stringLiteralNode => CreateLiteralMessage(stringLiteralNode.Type, '"' + stringLiteralNode.Value + '"'),
+//             BoolLiteralNode boolLiteralNode => CreateLiteralMessage(boolLiteralNode.Type, boolLiteralNode.Value.ToString()),
+//             Float32LiteralNode float32LiteralNode => CreateLiteralMessage(float32LiteralNode.Type, float32LiteralNode.Value.ToString(CultureInfo.InvariantCulture)),
+//             Float64LiteralNode float64LiteralNode => CreateLiteralMessage(float64LiteralNode.Type, float64LiteralNode.Value.ToString(CultureInfo.InvariantCulture)),
+//             I8LiteralNode i8LiteralNode => CreateLiteralMessage(i8LiteralNode.Type, i8LiteralNode.Value.ToString()),
+//             I16LiteralNode i16LiteralNode => CreateLiteralMessage(i16LiteralNode.Type, i16LiteralNode.Value.ToString()),
+//             I32LiteralNode i32LiteralNode => CreateLiteralMessage(i32LiteralNode.Type, i32LiteralNode.Value.ToString()),
+//             I64LiteralNode i64LiteralNode => CreateLiteralMessage(i64LiteralNode.Type, i64LiteralNode.Value.ToString()),
+//             U8LiteralNode u8LiteralNode => CreateLiteralMessage(u8LiteralNode.Type, u8LiteralNode.Value.ToString()),
+//             U16LiteralNode u16LiteralNode => CreateLiteralMessage(u16LiteralNode.Type, u16LiteralNode.Value.ToString()),
+//             U32LiteralNode u32LiteralNode => CreateLiteralMessage(u32LiteralNode.Type, u32LiteralNode.Value.ToString()),
+//             U64LiteralNode u64LiteralNode => CreateLiteralMessage(u64LiteralNode.Type, u64LiteralNode.Value.ToString()),
+//             // Expressions can have a generic fallback showing the resulting type
+//             ExpressionNode expressionNode => $"""
+//                                               **Expression** `{expressionNode.GetType().Name}`
+//                                               ```nub
+//                                               {expressionNode.Type}
+//                                               ```
+//                                               """,
+//             BlockNode => null,
+//             _ => hoveredNode.GetType().Name
+//         };
+//     }
+//
+//     private static string CreateLiteralMessage(NubType type, string value)
+//     {
+//         return $"""
+//                 **Literal** `{type}`
+//                 ```nub
+//                 {value}: {type}
+//                 ```
+//                 """;
+//     }
+//
+//     private static string CreateTypeNameMessage(string description, string name, NubType type)
+//     {
+//         return $"""
+//                 **{description}** `{name}`
+//                 ```nub
+//                 {name}: {type}
+//                 ```
+//                 """;
+//     }
+//
+//     private static string CreateFuncIdentifierMessage(FuncIdentifierNode funcIdentifierNode, CompilationUnit compilationUnit)
+//     {
+//         var func = compilationUnit.ImportedFunctions
+//             .Where(x => x.Key.Value == funcIdentifierNode.ModuleToken.Value)
+//             .SelectMany(x => x.Value)
+//             .FirstOrDefault(x => x.NameToken.Value == funcIdentifierNode.NameToken.Value);
+//
+//         if (func == null)
+//         {
+//             return $"""
+//                     **Function** `{funcIdentifierNode.ModuleToken.Value}::{funcIdentifierNode.NameToken.Value}`
+//                     ```nub
+//                     // Declaration not found
+//                     ```
+//                     """;
+//         }
+//
+//         return CreateFuncPrototypeMessage(func);
+//     }
+//
+//     private static string CreateFuncPrototypeMessage(FuncPrototypeNode funcPrototypeNode)
+//     {
+//         var parameterText = string.Join(", ", funcPrototypeNode.Parameters.Select(x => $"{x.NameToken.Value}: {x.Type}"));
+//         var externText = funcPrototypeNode.ExternSymbolToken != null ? $"extern \"{funcPrototypeNode.ExternSymbolToken.Value}\" " : "";
+//
+//         return $"""
+//                 **Function** `{funcPrototypeNode.NameToken.Value}`
+//                 ```nub
+//                 {externText}func {funcPrototypeNode.NameToken.Value}({parameterText}): {funcPrototypeNode.ReturnType}
+//                 ```
+//                 """;
+//     }
 }

compiler/NubLang.LSP/WorkspaceManager.cs

@@ -7,7 +7,7 @@ namespace NubLang.LSP;
 public class WorkspaceManager(DiagnosticsPublisher diagnosticsPublisher)
 {
     private readonly Dictionary<string, SyntaxTree> _syntaxTrees = new();
-    private readonly Dictionary<string, CompilationUnit> _compilationUnits = new();
+    private readonly Dictionary<string, List<TopLevelNode>> _compilationUnits = new();
 
     public void Init(string rootPath)
     {
@@ -34,6 +34,7 @@ public class WorkspaceManager(DiagnosticsPublisher diagnosticsPublisher)
             var typeChecker = new TypeChecker(syntaxTree, modules);
             var result = typeChecker.Check();
             diagnosticsPublisher.Publish(fsPath, typeChecker.Diagnostics);
+
             _compilationUnits[fsPath] = result;
         }
     }
@@ -57,6 +58,7 @@ public class WorkspaceManager(DiagnosticsPublisher diagnosticsPublisher)
         var typeChecker = new TypeChecker(syntaxTree, modules);
         var result = typeChecker.Check();
         diagnosticsPublisher.Publish(fsPath, typeChecker.Diagnostics);
+
         _compilationUnits[fsPath] = result;
     }
 
@@ -67,7 +69,7 @@ public class WorkspaceManager(DiagnosticsPublisher diagnosticsPublisher)
         _compilationUnits.Remove(fsPath);
     }
 
-    public CompilationUnit? GetCompilationUnit(DocumentUri path)
+    public List<TopLevelNode>? GetCompilationUnit(DocumentUri path)
     {
         return _compilationUnits.GetValueOrDefault(path.GetFileSystemPath());
     }

compiler/NubLang/Ast/CompilationUnit.cs

@@ -1,15 +1,12 @@
+using NubLang.Syntax;
+
 namespace NubLang.Ast;
 
-public sealed class CompilationUnit
-{
-    public CompilationUnit(List<FuncNode> functions, List<NubStructType> importedStructTypes, List<FuncPrototypeNode> importedFunctions)
-    {
-        Functions = functions;
-        ImportedStructTypes = importedStructTypes;
-        ImportedFunctions = importedFunctions;
-    }
-
-    public List<FuncNode> Functions { get; }
-    public List<NubStructType> ImportedStructTypes { get; }
-    public List<FuncPrototypeNode> ImportedFunctions { get; }
-}
+// public sealed class CompilationUnit(IdentifierToken module, List<FuncNode> functions, List<StructNode> structTypes, Dictionary<IdentifierToken, List<NubStructType>> importedStructTypes, Dictionary<IdentifierToken, List<FuncPrototypeNode>> importedFunctions)
+// {
+//     public IdentifierToken Module { get; } = module;
+//     public List<FuncNode> Functions { get; } = functions;
+//     public List<StructNode> Structs { get; } = structTypes;
+//     public Dictionary<IdentifierToken, List<NubStructType>> ImportedStructTypes { get; } = importedStructTypes;
+//     public Dictionary<IdentifierToken, List<FuncPrototypeNode>> ImportedFunctions { get; } = importedFunctions;
+// }

compiler/NubLang/Ast/Node.cs

@@ -29,17 +29,38 @@ public abstract class Node(List<Token> tokens)
     }
 }
 
-#region Definitions
+public abstract class TopLevelNode(List<Token> tokens) : Node(tokens);
 
-public abstract class DefinitionNode(List<Token> tokens, string module, string name) : Node(tokens)
+public class ImportNode(List<Token> tokens, IdentifierToken nameToken) : TopLevelNode(tokens)
 {
-    public string Module { get; } = module;
-    public string Name { get; } = name;
+    public IdentifierToken NameToken { get; } = nameToken;
+
+    public override IEnumerable<Node> Children()
+    {
+        return [];
+    }
 }
 
-public class FuncParameterNode(List<Token> tokens, string name, NubType type) : Node(tokens)
+public class ModuleNode(List<Token> tokens, IdentifierToken nameToken) : TopLevelNode(tokens)
 {
-    public string Name { get; } = name;
+    public IdentifierToken NameToken { get; } = nameToken;
+
+    public override IEnumerable<Node> Children()
+    {
+        return [];
+    }
+}
+
+#region Definitions
+
+public abstract class DefinitionNode(List<Token> tokens, IdentifierToken nameToken) : TopLevelNode(tokens)
+{
+    public IdentifierToken NameToken { get; } = nameToken;
+}
+
+public class FuncParameterNode(List<Token> tokens, IdentifierToken nameToken, NubType type) : Node(tokens)
+{
+    public IdentifierToken NameToken { get; } = nameToken;
     public NubType Type { get; } = type;
 
     public override IEnumerable<Node> Children()
@@ -48,11 +69,10 @@ public class FuncParameterNode(List<Token> tokens, string name, NubType type) :
     }
 }
 
-public class FuncPrototypeNode(List<Token> tokens, string module, string name, string? externSymbol, List<FuncParameterNode> parameters, NubType returnType) : Node(tokens)
+public class FuncPrototypeNode(List<Token> tokens, IdentifierToken nameToken, StringLiteralToken? externSymbolToken, List<FuncParameterNode> parameters, NubType returnType) : Node(tokens)
 {
-    public string Module { get; } = module;
-    public string Name { get; } = name;
-    public string? ExternSymbol { get; } = externSymbol;
+    public IdentifierToken NameToken { get; } = nameToken;
+    public StringLiteralToken? ExternSymbolToken { get; } = externSymbolToken;
     public List<FuncParameterNode> Parameters { get; } = parameters;
     public NubType ReturnType { get; } = returnType;
 
@@ -62,7 +82,7 @@ public class FuncPrototypeNode(List<Token> tokens, string module, string name, s
     }
 }
 
-public class FuncNode(List<Token> tokens, FuncPrototypeNode prototype, BlockNode? body) : DefinitionNode(tokens, prototype.Module, prototype.Name)
+public class FuncNode(List<Token> tokens, FuncPrototypeNode prototype, BlockNode? body) : DefinitionNode(tokens, prototype.NameToken)
 {
     public FuncPrototypeNode Prototype { get; } = prototype;
     public BlockNode? Body { get; } = body;
@@ -77,6 +97,35 @@ public class FuncNode(List<Token> tokens, FuncPrototypeNode prototype, BlockNode
     }
 }
 
+public class StructFieldNode(List<Token> tokens, IdentifierToken nameToken, NubType type, ExpressionNode? value) : Node(tokens)
+{
+    public IdentifierToken NameToken { get; } = nameToken;
+    public NubType Type { get; } = type;
+    public ExpressionNode? Value { get; } = value;
+
+    public override IEnumerable<Node> Children()
+    {
+        if (Value != null)
+        {
+            yield return Value;
+        }
+    }
+}
+
+public class StructNode(List<Token> tokens, IdentifierToken name, NubStructType structType, List<StructFieldNode> fields) : DefinitionNode(tokens, name)
+{
+    public NubStructType StructType { get; } = structType;
+    public List<StructFieldNode> Fields { get; } = fields;
+
+    public override IEnumerable<Node> Children()
+    {
+        foreach (var field in Fields)
+        {
+            yield return field;
+        }
+    }
+}
+
 #endregion
 
 #region Statements
@@ -144,9 +193,9 @@ public class IfNode(List<Token> tokens, ExpressionNode condition, BlockNode body
     }
 }
 
-public class VariableDeclarationNode(List<Token> tokens, string name, ExpressionNode? assignment, NubType type) : StatementNode(tokens)
+public class VariableDeclarationNode(List<Token> tokens, IdentifierToken nameToken, ExpressionNode? assignment, NubType type) : StatementNode(tokens)
 {
-    public string Name { get; } = name;
+    public IdentifierToken NameToken { get; } = nameToken;
     public ExpressionNode? Assignment { get; } = assignment;
     public NubType Type { get; } = type;
 
@@ -184,10 +233,10 @@ public class WhileNode(List<Token> tokens, ExpressionNode condition, BlockNode b
     }
 }
 
-public class ForSliceNode(List<Token> tokens, string elementName, string? indexName, ExpressionNode target, BlockNode body) : StatementNode(tokens)
+public class ForSliceNode(List<Token> tokens, IdentifierToken elementNameToken, IdentifierToken? indexNameToken, ExpressionNode target, BlockNode body) : StatementNode(tokens)
 {
-    public string ElementName { get; } = elementName;
-    public string? IndexName { get; } = indexName;
+    public IdentifierToken ElementNameToken { get; } = elementNameToken;
+    public IdentifierToken? IndexNameToken { get; } = indexNameToken;
     public ExpressionNode Target { get; } = target;
     public BlockNode Body { get; } = body;
 
@@ -198,10 +247,10 @@ public class ForSliceNode(List<Token> tokens, string elementName, string? indexN
     }
 }
 
-public class ForConstArrayNode(List<Token> tokens, string elementName, string? indexName, ExpressionNode target, BlockNode body) : StatementNode(tokens)
+public class ForConstArrayNode(List<Token> tokens, IdentifierToken elementNameToken, IdentifierToken? indexNameToken, ExpressionNode target, BlockNode body) : StatementNode(tokens)
 {
-    public string ElementName { get; } = elementName;
-    public string? IndexName { get; } = indexName;
+    public IdentifierToken ElementNameToken { get; } = elementNameToken;
+    public IdentifierToken? IndexNameToken { get; } = indexNameToken;
     public ExpressionNode Target { get; } = target;
     public BlockNode Body { get; } = body;
 
@@ -385,7 +434,7 @@ public class Float64LiteralNode(List<Token> tokens, double value) : RValueExpres
     }
 }
 
-public class BoolLiteralNode(List<Token> tokens, NubType type, bool value) : RValueExpressionNode(tokens, type)
+public class BoolLiteralNode(List<Token> tokens, bool value) : RValueExpressionNode(tokens, new NubBoolType())
 {
     public bool Value { get; } = value;
 
@@ -434,9 +483,9 @@ public class FuncCallNode(List<Token> tokens, NubType type, ExpressionNode expre
     }
 }
 
-public class VariableIdentifierNode(List<Token> tokens, NubType type, string name) : LValueExpressionNode(tokens, type)
+public class VariableIdentifierNode(List<Token> tokens, NubType type, IdentifierToken nameToken) : LValueExpressionNode(tokens, type)
 {
-    public string Name { get; } = name;
+    public IdentifierToken NameToken { get; } = nameToken;
 
     public override IEnumerable<Node> Children()
     {
@@ -444,11 +493,11 @@ public class VariableIdentifierNode(List<Token> tokens, NubType type, string nam
     }
 }
 
-public class FuncIdentifierNode(List<Token> tokens, NubType type, string module, string name, string? externSymbol) : RValueExpressionNode(tokens, type)
+public class FuncIdentifierNode(List<Token> tokens, NubType type, IdentifierToken moduleToken, IdentifierToken nameToken, StringLiteralToken? externSymbolToken) : RValueExpressionNode(tokens, type)
 {
-    public string Module { get; } = module;
-    public string Name { get; } = name;
-    public string? ExternSymbol { get; } = externSymbol;
+    public IdentifierToken ModuleToken { get; } = moduleToken;
+    public IdentifierToken NameToken { get; } = nameToken;
+    public StringLiteralToken? ExternSymbolToken { get; } = externSymbolToken;
 
     public override IEnumerable<Node> Children()
     {
@@ -522,10 +571,10 @@ public class AddressOfNode(List<Token> tokens, NubType type, LValueExpressionNod
     }
 }
 
-public class StructFieldAccessNode(List<Token> tokens, NubType type, ExpressionNode target, string field) : LValueExpressionNode(tokens, type)
+public class StructFieldAccessNode(List<Token> tokens, NubType type, ExpressionNode target, IdentifierToken fieldToken) : LValueExpressionNode(tokens, type)
 {
     public ExpressionNode Target { get; } = target;
-    public string Field { get; } = field;
+    public IdentifierToken FieldToken { get; } = fieldToken;
 
     public override IEnumerable<Node> Children()
     {
@@ -533,9 +582,9 @@ public class StructFieldAccessNode(List<Token> tokens, NubType type, ExpressionN
     }
 }
 
-public class StructInitializerNode(List<Token> tokens, NubType type, Dictionary<string, ExpressionNode> initializers) : RValueExpressionNode(tokens, type)
+public class StructInitializerNode(List<Token> tokens, NubType type, Dictionary<IdentifierToken, ExpressionNode> initializers) : RValueExpressionNode(tokens, type)
 {
-    public Dictionary<string, ExpressionNode> Initializers { get; } = initializers;
+    public Dictionary<IdentifierToken, ExpressionNode> Initializers { get; } = initializers;
 
     public override IEnumerable<Node> Children()
     {
@@ -556,6 +605,16 @@ public class DereferenceNode(List<Token> tokens, NubType type, ExpressionNode ta
     }
 }
 
+public class RefDereferenceNode(List<Token> tokens, NubType type, ExpressionNode target) : LValueExpressionNode(tokens, type)
+{
+    public ExpressionNode Target { get; } = target;
+
+    public override IEnumerable<Node> Children()
+    {
+        yield return Target;
+    }
+}
+
 public class SizeNode(List<Token> tokens, NubType TargetType) : RValueExpressionNode(tokens, new NubIntType(false, 64))
 {
     public NubType TargetType { get; } = TargetType;
@@ -576,10 +635,23 @@ public class CastNode(List<Token> tokens, NubType type, ExpressionNode value) :
     }
 }
 
-public class EnumReferenceIntermediateNode(List<Token> tokens, string module, string name) : IntermediateExpression(tokens)
+public class RefStructInitializerNode(List<Token> tokens, NubType type, Dictionary<IdentifierToken, ExpressionNode> initializers) : RValueExpressionNode(tokens, type)
 {
-    public string Module { get; } = module;
-    public string Name { get; } = name;
+    public Dictionary<IdentifierToken, ExpressionNode> Initializers { get; } = initializers;
+
+    public override IEnumerable<Node> Children()
+    {
+        foreach (var initializer in Initializers)
+        {
+            yield return initializer.Value;
+        }
+    }
+}
+
+public class EnumReferenceIntermediateNode(List<Token> tokens, IdentifierToken moduleToken, IdentifierToken nameToken) : IntermediateExpression(tokens)
+{
+    public IdentifierToken ModuleToken { get; } = moduleToken;
+    public IdentifierToken NameToken { get; } = nameToken;
 
     public override IEnumerable<Node> Children()
     {

compiler/NubLang/Ast/NubType.cs

@@ -57,6 +57,15 @@ public sealed class NubPointerType(NubType baseType) : NubType
     public override int GetHashCode() => HashCode.Combine(typeof(NubPointerType), BaseType);
 }
 
+public class NubRefType(NubType baseType) : NubType
+{
+    public NubType BaseType { get; } = baseType;
+
+    public override string ToString() => "&" + BaseType;
+    public override bool Equals(NubType? other) => other is NubRefType;
+    public override int GetHashCode() => HashCode.Combine(typeof(NubRefType));
+}
+
 public class NubFuncType(List<NubType> parameters, NubType returnType) : NubType
 {
     public List<NubType> Parameters { get; } = parameters;
@@ -106,10 +115,10 @@ public class NubSliceType(NubType elementType) : NubType
     public override int GetHashCode() => HashCode.Combine(typeof(NubSliceType), ElementType);
 }
 
-public class NubConstArrayType(NubType elementType, long size) : NubType
+public class NubConstArrayType(NubType elementType, ulong size) : NubType
 {
     public NubType ElementType { get; } = elementType;
-    public long Size { get; } = size;
+    public ulong Size { get; } = size;
 
     public override string ToString() => $"[{Size}]{ElementType}";
     public override bool Equals(NubType? other) => other is NubConstArrayType array && ElementType.Equals(array.ElementType) && Size == array.Size;

compiler/NubLang/Ast/TypeResolver.cs

@@ -0,0 +1,97 @@
+using NubLang.Diagnostics;
+using NubLang.Syntax;
+
+namespace NubLang.Ast;
+
+public class TypeResolver
+{
+    private readonly Dictionary<string, Module> _modules;
+    private readonly Dictionary<(string Module, string Name), NubType> _typeCache = new();
+    private readonly HashSet<(string Module, string Name)> _resolvingTypes = [];
+
+    public TypeResolver(Dictionary<string, Module> modules)
+    {
+        _modules = modules;
+    }
+
+    public NubType ResolveType(TypeSyntax type, string currentModule)
+    {
+        return type switch
+        {
+            ArrayTypeSyntax arr => new NubArrayType(ResolveType(arr.BaseType, currentModule)),
+            BoolTypeSyntax => new NubBoolType(),
+            IntTypeSyntax i => new NubIntType(i.Signed, i.Width),
+            FloatTypeSyntax f => new NubFloatType(f.Width),
+            FuncTypeSyntax func => new NubFuncType(func.Parameters.Select(x => ResolveType(x, currentModule)).ToList(), ResolveType(func.ReturnType, currentModule)),
+            SliceTypeSyntax slice => new NubSliceType(ResolveType(slice.BaseType, currentModule)),
+            ConstArrayTypeSyntax arr => new NubConstArrayType(ResolveType(arr.BaseType, currentModule), arr.Size),
+            PointerTypeSyntax ptr => new NubPointerType(ResolveType(ptr.BaseType, currentModule)),
+            RefTypeSyntax r => new NubRefType(ResolveType(r.BaseType, currentModule)),
+            StringTypeSyntax => new NubStringType(),
+            CustomTypeSyntax c => ResolveCustomType(c, currentModule),
+            VoidTypeSyntax => new NubVoidType(),
+            _ => throw new NotSupportedException($"Unknown type syntax: {type}")
+        };
+    }
+
+    private NubType ResolveCustomType(CustomTypeSyntax customType, string currentModule)
+    {
+        var module = _modules[customType.ModuleToken?.Value ?? currentModule];
+
+        var enumDef = module.Enums(true).FirstOrDefault(x => x.NameToken.Value == customType.NameToken.Value);
+        if (enumDef != null)
+        {
+            return enumDef.Type != null ? ResolveType(enumDef.Type, currentModule) : new NubIntType(false, 64);
+        }
+
+        var structDef = module.Structs(true).FirstOrDefault(x => x.NameToken.Value == customType.NameToken.Value);
+        if (structDef != null)
+        {
+            var key = (customType.ModuleToken?.Value ?? currentModule, customType.NameToken.Value);
+
+            if (_typeCache.TryGetValue(key, out var cachedType))
+            {
+                return cachedType;
+            }
+
+            if (!_resolvingTypes.Add(key))
+            {
+                var placeholder = new NubStructType(customType.ModuleToken?.Value ?? currentModule, customType.NameToken.Value, []);
+                _typeCache[key] = placeholder;
+                return placeholder;
+            }
+
+            try
+            {
+                var result = new NubStructType(customType.ModuleToken?.Value ?? currentModule, structDef.NameToken.Value, []);
+                _typeCache[key] = result;
+
+                var fields = structDef.Fields
+                    .Select(x => new NubStructFieldType(x.NameToken.Value, ResolveType(x.Type, currentModule), x.Value != null))
+                    .ToList();
+
+                result.Fields.AddRange(fields);
+                return result;
+            }
+            finally
+            {
+                _resolvingTypes.Remove(key);
+            }
+        }
+
+        throw new TypeResolverException(Diagnostic
+            .Error($"Type {customType.NameToken.Value} not found in module {customType.ModuleToken?.Value ?? currentModule}")
+            .At(customType)
+            .Build());
+    }
+}
+
+public class TypeResolverException : Exception
+{
+    public Diagnostic Diagnostic { get; }
+
+    public TypeResolverException(Diagnostic diagnostic) : base(diagnostic.Message)
+    {
+        Diagnostic = diagnostic;
+    }
+}

compiler/NubLang/Diagnostics/CompileException.cs

@@ -0,0 +1,11 @@
+namespace NubLang.Diagnostics;
+
+public class CompileException : Exception
+{
+    public Diagnostic Diagnostic { get; }
+
+    public CompileException(Diagnostic diagnostic) : base(diagnostic.Message)
+    {
+        Diagnostic = diagnostic;
+    }
+}

compiler/NubLang/Generation/CType.cs

@@ -10,15 +10,16 @@ public static class CType
         {
             NubVoidType => "void" + (variableName != null ? $" {variableName}" : ""),
             NubBoolType => "bool" + (variableName != null ? $" {variableName}" : ""),
-            NubIntType intType => CreateIntType(intType, variableName),
-            NubFloatType floatType => CreateFloatType(floatType, variableName),
-            NubPointerType ptr => CreatePointerType(ptr, variableName),
-            NubSliceType => "struct nub_slice" + (variableName != null ? $" {variableName}" : ""),
-            NubStringType => "struct nub_string" + (variableName != null ? $" {variableName}" : ""),
-            NubConstArrayType arr => CreateConstArrayType(arr, variableName, constArraysAsPointers),
-            NubArrayType arr => CreateArrayType(arr, variableName),
-            NubFuncType fn => CreateFuncType(fn, variableName),
-            NubStructType st => $"struct {st.Module}_{st.Name}_{NameMangler.Mangle(st)}" + (variableName != null ? $" {variableName}" : ""),
+            NubIntType i => CreateIntType(i, variableName),
+            NubFloatType f => CreateFloatType(f, variableName),
+            NubPointerType p => CreatePointerType(p, variableName),
+            NubRefType r => CreateRefType(r, variableName),
+            NubSliceType => "nub_slice" + (variableName != null ? $" {variableName}" : ""),
+            NubStringType => "nub_string" + (variableName != null ? $" {variableName}" : ""),
+            NubConstArrayType a => CreateConstArrayType(a, variableName, constArraysAsPointers),
+            NubArrayType a => CreateArrayType(a, variableName),
+            NubFuncType f => CreateFuncType(f, variableName),
+            NubStructType s => $"{s.Module}_{s.Name}_{NameMangler.Mangle(s)}" + (variableName != null ? $" {variableName}" : ""),
             _ => throw new NotSupportedException($"C type generation not supported for: {type}")
         };
     }
@@ -47,6 +48,12 @@ public static class CType
         return cType + (varName != null ? $" {varName}" : "");
     }
 
+    private static string CreateRefType(NubRefType ptr, string? varName)
+    {
+        var baseType = Create(ptr.BaseType);
+        return baseType + "*" + (varName != null ? $" {varName}" : "");
+    }
+
     private static string CreatePointerType(NubPointerType ptr, string? varName)
     {
         var baseType = Create(ptr.BaseType);

compiler/NubLang/Generation/Generator.cs

@@ -7,12 +7,14 @@ namespace NubLang.Generation;
 
 public class Generator
 {
-    private readonly CompilationUnit _compilationUnit;
+    private readonly List<TopLevelNode> _compilationUnit;
     private readonly IndentedTextWriter _writer;
-    private readonly Stack<List<DeferNode>> _deferStack = [];
+    private readonly Stack<Scope> _scopes = [];
     private int _tmpIndex;
 
-    public Generator(CompilationUnit compilationUnit)
+    private Scope Scope => _scopes.Peek();
+
+    public Generator(List<TopLevelNode> compilationUnit)
     {
         _compilationUnit = compilationUnit;
         _writer = new IndentedTextWriter();
@@ -29,68 +31,76 @@ public class Generator
         return externSymbol ?? $"{module}_{name}";
     }
 
+    private string GetModuleName()
+    {
+        return _compilationUnit.OfType<ModuleNode>().First().NameToken.Value;
+    }
+
     public string Emit()
     {
-        _writer.WriteLine("""
-                          struct nub_string
-                          {
-                              unsigned long long length;
-                              char *data;
-                          };
-
-                          struct nub_slice
-                          {
-                              unsigned long long length;
-                              void *data;
-                          };
-
-                          """);
-
-        foreach (var structType in _compilationUnit.ImportedStructTypes)
+        foreach (var structType in _compilationUnit.OfType<StructNode>())
         {
-            _writer.WriteLine(CType.Create(structType));
+            _writer.WriteLine($"void {CType.Create(structType.StructType)}_create({CType.Create(structType.StructType)} *self)");
             _writer.WriteLine("{");
             using (_writer.Indent())
             {
                 foreach (var field in structType.Fields)
                 {
-                    _writer.WriteLine($"{CType.Create(field.Type, field.Name, constArraysAsPointers: false)};");
+                    if (field.Value != null)
+                    {
+                        var value = EmitExpression(field.Value);
+                        _writer.WriteLine($"self->{field.NameToken.Value} = {value}");
+                    }
                 }
             }
 
-            _writer.WriteLine("};");
+            _writer.WriteLine("}");
             _writer.WriteLine();
-        }
 
-        // note(nub31): Forward declarations
-        foreach (var prototype in _compilationUnit.ImportedFunctions)
-        {
-            EmitLine(prototype.Tokens.FirstOrDefault());
-            var parameters = prototype.Parameters.Count != 0
-                ? string.Join(", ", prototype.Parameters.Select(x => CType.Create(x.Type, x.Name)))
-                : "void";
+            _writer.WriteLine($"void {CType.Create(structType.StructType)}_destroy({CType.Create(structType.StructType)} *self)");
+            _writer.WriteLine("{");
+            using (_writer.Indent())
+            {
+                foreach (var field in structType.Fields)
+                {
+                    if (field.Type is NubRefType)
+                    {
+                        _writer.WriteLine($"rc_release(self->{field.NameToken.Value});");
+                    }
+                }
+            }
 
-            var name = FuncName(prototype.Module, prototype.Name, prototype.ExternSymbol);
-            _writer.WriteLine($"{CType.Create(prototype.ReturnType, name)}({parameters});");
+            _writer.WriteLine("}");
             _writer.WriteLine();
         }
 
         // note(nub31): Normal functions
-        foreach (var funcNode in _compilationUnit.Functions)
+        foreach (var funcNode in _compilationUnit.OfType<FuncNode>())
         {
             if (funcNode.Body == null) continue;
 
             EmitLine(funcNode.Tokens.FirstOrDefault());
             var parameters = funcNode.Prototype.Parameters.Count != 0
-                ? string.Join(", ", funcNode.Prototype.Parameters.Select(x => CType.Create(x.Type, x.Name)))
+                ? string.Join(", ", funcNode.Prototype.Parameters.Select(x => CType.Create(x.Type, x.NameToken.Value)))
                 : "void";
 
-            var name = FuncName(funcNode.Module, funcNode.Name, funcNode.Prototype.ExternSymbol);
+            var name = FuncName(GetModuleName(), funcNode.NameToken.Value, funcNode.Prototype.ExternSymbolToken?.Value);
             _writer.WriteLine($"{CType.Create(funcNode.Prototype.ReturnType, name)}({parameters})");
             _writer.WriteLine("{");
             using (_writer.Indent())
             {
-                EmitBlock(funcNode.Body);
+                using (BeginScope())
+                {
+                    foreach (var parameter in funcNode.Prototype.Parameters)
+                    {
+                        if (parameter.Type is NubRefType)
+                        {
+                            Scope.Defer(() => _writer.WriteLine($"rc_release({parameter.NameToken.Value});"));
+                        }
+                    }
+
+                    EmitBlock(funcNode.Body);
+                }
             }
 
             _writer.WriteLine("}");
@@ -112,7 +122,10 @@ public class Generator
                 _writer.WriteLine("{");
                 using (_writer.Indent())
                 {
-                    EmitBlock(blockNode);
+                    using (BeginScope())
+                    {
+                        EmitBlock(blockNode);
+                    }
                 }
 
                 _writer.WriteLine("}");
@@ -124,7 +137,7 @@ public class Generator
                 EmitContinue(continueNode);
                 break;
             case DeferNode deferNode:
-                EmitDefer(deferNode);
+                Scope.Defer(() => EmitStatement(deferNode.Statement));
                 break;
             case ForConstArrayNode forConstArrayNode:
                 EmitForConstArray(forConstArrayNode);
@@ -164,6 +177,14 @@ public class Generator
     {
         var target = EmitExpression(assignmentNode.Target);
         var value = EmitExpression(assignmentNode.Value);
+
+        if (assignmentNode.Target.Type is NubRefType)
+        {
+            _writer.WriteLine($"rc_retain({value});");
+            Scope.Defer(() => _writer.WriteLine($"rc_release({value});"));
+            _writer.WriteLine($"rc_release({target});");
+        }
+
         _writer.WriteLine($"{target} = {value};");
     }
 
@@ -179,23 +200,21 @@ public class Generator
         _writer.WriteLine("continue;");
     }
 
-    private void EmitDefer(DeferNode deferNode)
-    {
-        _deferStack.Peek().Add(deferNode);
-    }
-
     private void EmitForSlice(ForSliceNode forSliceNode)
     {
         var targetType = (NubSliceType)forSliceNode.Target.Type;
         var target = EmitExpression(forSliceNode.Target);
-        var indexName = forSliceNode.IndexName ?? NewTmp();
+        var indexName = forSliceNode.IndexNameToken?.Value ?? NewTmp();
 
         _writer.WriteLine($"for (unsigned long long {indexName} = 0; {indexName} < {target}.length; ++{indexName})");
         _writer.WriteLine("{");
         using (_writer.Indent())
         {
-            _writer.WriteLine($"{CType.Create(targetType.ElementType, forSliceNode.ElementName)} = (({CType.Create(targetType.ElementType)}*){target}.data)[{indexName}];");
-            EmitBlock(forSliceNode.Body);
+            using (BeginScope())
+            {
+                _writer.WriteLine($"{CType.Create(targetType.ElementType, forSliceNode.ElementNameToken.Value)} = (({CType.Create(targetType.ElementType)}*){target}.data)[{indexName}];");
+                EmitBlock(forSliceNode.Body);
+            }
         }
 
         _writer.WriteLine("}");
@@ -205,14 +224,17 @@ public class Generator
     {
         var targetType = (NubConstArrayType)forConstArrayNode.Target.Type;
         var target = EmitExpression(forConstArrayNode.Target);
-        var indexName = forConstArrayNode.IndexName ?? NewTmp();
+        var indexName = forConstArrayNode.IndexNameToken?.Value ?? NewTmp();
 
         _writer.WriteLine($"for (unsigned long long {indexName} = 0; {indexName} < {targetType.Size}; ++{indexName})");
         _writer.WriteLine("{");
         using (_writer.Indent())
         {
-            _writer.WriteLine($"{CType.Create(targetType.ElementType, forConstArrayNode.ElementName)} = {target}[{indexName}];");
-            EmitBlock(forConstArrayNode.Body);
+            using (BeginScope())
+            {
+                _writer.WriteLine($"{CType.Create(targetType.ElementType, forConstArrayNode.ElementNameToken.Value)} = {target}[{indexName}];");
+                EmitBlock(forConstArrayNode.Body);
+            }
         }
 
         _writer.WriteLine("}");
@@ -225,7 +247,10 @@ public class Generator
         _writer.WriteLine("{");
         using (_writer.Indent())
         {
-            EmitBlock(ifNode.Body);
+            using (BeginScope())
+            {
+                EmitBlock(ifNode.Body);
+            }
         }
 
         _writer.WriteLine("}");
@@ -238,7 +263,10 @@ public class Generator
                 _writer.WriteLine("{");
                 using (_writer.Indent())
                 {
-                    EmitBlock(elseNode);
+                    using (BeginScope())
+                    {
+                        EmitBlock(elseNode);
+                    }
                 }
 
                 _writer.WriteLine("}");
@@ -250,44 +278,28 @@ public class Generator
     {
         if (returnNode.Value == null)
         {
-            var blockDefers = _deferStack.Peek();
-            for (var i = blockDefers.Count - 1; i >= 0; i--)
-            {
-                EmitStatement(blockDefers[i].Statement);
-            }
-
+            EmitScopeCleanup();
             _writer.WriteLine("return;");
         }
         else
         {
             var returnValue = EmitExpression(returnNode.Value);
-
-            if (_deferStack.Peek().Count != 0)
+            var tmp = NewTmp();
+            _writer.WriteLine($"{CType.Create(returnNode.Value.Type, tmp)} = {returnValue};");
+            if (returnNode.Value.Type is NubRefType)
             {
-                var tmp = NewTmp();
-                _writer.WriteLine($"{CType.Create(returnNode.Value.Type, tmp)} = {returnValue};");
-
-                var blockDefers = _deferStack.Peek();
-                for (var i = blockDefers.Count - 1; i >= 0; i--)
-                {
-                    EmitStatement(blockDefers[i].Statement);
-                }
-
-                EmitLine(returnNode.Tokens.FirstOrDefault());
-                _writer.WriteLine($"return {tmp};");
-            }
-            else
-            {
-                EmitLine(returnNode.Tokens.FirstOrDefault());
-                _writer.WriteLine($"return {returnValue};");
+                _writer.WriteLine($"rc_retain({tmp});");
             }
+
+            EmitScopeCleanup();
+            EmitLine(returnNode.Tokens.FirstOrDefault());
+            _writer.WriteLine($"return {tmp};");
         }
     }
 
     private void EmitStatementFuncCall(StatementFuncCallNode statementFuncCallNode)
     {
-        var funcCall = EmitFuncCall(statementFuncCallNode.FuncCall);
-        _writer.WriteLine($"{funcCall};");
+        EmitFuncCall(statementFuncCallNode.FuncCall);
     }
 
     private void EmitVariableDeclaration(VariableDeclarationNode variableDeclarationNode)
@@ -295,11 +307,18 @@ public class Generator
         if (variableDeclarationNode.Assignment != null)
         {
             var value = EmitExpression(variableDeclarationNode.Assignment);
-            _writer.WriteLine($"{CType.Create(variableDeclarationNode.Type, variableDeclarationNode.Name)} = {value};");
+
+            if (variableDeclarationNode.Type is NubRefType)
+            {
+                _writer.WriteLine($"rc_retain({value});");
+                Scope.Defer(() => _writer.WriteLine($"rc_release({value});"));
+            }
+
+            _writer.WriteLine($"{CType.Create(variableDeclarationNode.Type, variableDeclarationNode.NameToken.Value)} = {value};");
         }
         else
         {
-            _writer.WriteLine($"{CType.Create(variableDeclarationNode.Type, variableDeclarationNode.Name)};");
+            _writer.WriteLine($"{CType.Create(variableDeclarationNode.Type, variableDeclarationNode.NameToken.Value)};");
         }
     }
 
@@ -310,7 +329,10 @@ public class Generator
         _writer.WriteLine("{");
         using (_writer.Indent())
         {
-            EmitBlock(whileNode.Body);
+            using (BeginScope())
+            {
+                EmitBlock(whileNode.Body);
+            }
         }
 
         _writer.WriteLine("}");
@@ -337,8 +359,10 @@ public class Generator
             Float64LiteralNode float64LiteralNode => EmitFloat64Literal(float64LiteralNode),
             CastNode castNode => EmitCast(castNode),
             FuncCallNode funcCallNode => EmitFuncCall(funcCallNode),
-            FuncIdentifierNode funcIdentifierNode => FuncName(funcIdentifierNode.Module, funcIdentifierNode.Name, funcIdentifierNode.ExternSymbol),
+            FuncIdentifierNode funcIdentifierNode => FuncName(funcIdentifierNode.ModuleToken.Value, funcIdentifierNode.NameToken.Value, funcIdentifierNode.ExternSymbolToken?.Value),
             AddressOfNode addressOfNode => EmitAddressOf(addressOfNode),
+            RefDereferenceNode refDereferenceNode => EmitRefDereference(refDereferenceNode),
+            RefStructInitializerNode refStructInitializerNode => EmitRefStructInitializer(refStructInitializerNode),
             SizeNode sizeBuiltinNode => $"sizeof({CType.Create(sizeBuiltinNode.TargetType)})",
             SliceIndexAccessNode sliceIndexAccessNode => EmitSliceArrayIndexAccess(sliceIndexAccessNode),
             StringLiteralNode stringLiteralNode => EmitStringLiteral(stringLiteralNode),
@@ -353,7 +377,7 @@ public class Generator
             U32LiteralNode u32LiteralNode => EmitU32Literal(u32LiteralNode),
             U64LiteralNode u64LiteralNode => EmitU64Literal(u64LiteralNode),
             UnaryExpressionNode unaryExpressionNode => EmitUnaryExpression(unaryExpressionNode),
-            VariableIdentifierNode variableIdentifierNode => variableIdentifierNode.Name,
+            VariableIdentifierNode variableIdentifierNode => variableIdentifierNode.NameToken.Value,
             _ => throw new ArgumentOutOfRangeException(nameof(expressionNode))
         };
 
@@ -473,8 +497,29 @@ public class Generator
     private string EmitFuncCall(FuncCallNode funcCallNode)
     {
         var name = EmitExpression(funcCallNode.Expression);
-        var parameterNames = funcCallNode.Parameters.Select(EmitExpression).ToList();
-        return $"{name}({string.Join(", ", parameterNames)})";
+
+        var parameterNames = new List<string>();
+        foreach (var parameter in funcCallNode.Parameters)
+        {
+            var result = EmitExpression(parameter);
+            if (parameter.Type is NubRefType)
+            {
+                _writer.WriteLine($"rc_retain({result});");
+            }
+
+            parameterNames.Add(result);
+        }
+
+        var tmp = NewTmp();
+
+        _writer.WriteLine($"{CType.Create(funcCallNode.Type)} {tmp} = {name}({string.Join(", ", parameterNames)});");
+
+        if (funcCallNode.Type is NubRefType)
+        {
+            Scope.Defer(() => _writer.WriteLine($"rc_release({tmp});"));
+        }
+
+        return tmp;
     }
 
     private string EmitAddressOf(AddressOfNode addressOfNode)
@@ -483,6 +528,33 @@ public class Generator
         return $"&{value}";
     }
 
+    private string EmitRefDereference(RefDereferenceNode refDereferenceNode)
+    {
+        var pointer = EmitExpression(refDereferenceNode.Target);
+        return $"*{pointer}";
+    }
+
+    private string EmitRefStructInitializer(RefStructInitializerNode refStructInitializerNode)
+    {
+        var type = (NubRefType)refStructInitializerNode.Type;
+        var structType = (NubStructType)type.BaseType;
+
+        var tmp = NewTmp();
+        _writer.WriteLine($"{CType.Create(type)} {tmp} = ({CType.Create(type)})rc_alloc(sizeof({CType.Create(structType)}), (void (*)(void *)){CType.Create(structType)}_destroy);");
+        Scope.Defer(() => _writer.WriteLine($"rc_release({tmp});"));
+
+        _writer.WriteLine($"*{tmp} = ({CType.Create(structType)}){{{0}}};");
+        _writer.WriteLine($"{CType.Create(structType)}_create({tmp});");
+
+        foreach (var initializer in refStructInitializerNode.Initializers)
+        {
+            var value = EmitExpression(initializer.Value);
+            _writer.WriteLine($"{tmp}->{initializer.Key} = {value};");
+        }
+
+        return tmp;
+    }
+
     private string EmitSliceArrayIndexAccess(SliceIndexAccessNode sliceIndexAccessNode)
     {
         var targetType = (NubSliceType)sliceIndexAccessNode.Target.Type;
@@ -495,29 +567,30 @@ public class Generator
     private string EmitStringLiteral(StringLiteralNode stringLiteralNode)
     {
         var length = Encoding.UTF8.GetByteCount(stringLiteralNode.Value);
-        return $"(nub_string){{.length = {length}, .data = \"{stringLiteralNode.Value}\"}}";
+        return $"({CType.Create(stringLiteralNode.Type)}){{.length = {length}, .data = \"{stringLiteralNode.Value}\"}}";
     }
 
     private string EmitStructFieldAccess(StructFieldAccessNode structFieldAccessNode)
     {
         var structExpr = EmitExpression(structFieldAccessNode.Target);
-        return $"{structExpr}.{structFieldAccessNode.Field}";
+        return $"{structExpr}.{structFieldAccessNode.FieldToken.Value}";
     }
 
     private string EmitStructInitializer(StructInitializerNode structInitializerNode)
     {
-        var initValues = new List<string>();
+        var structType = (NubStructType)structInitializerNode.Type;
+
+        var tmp = NewTmp();
+        _writer.WriteLine($"{CType.Create(structType)} {tmp} = ({CType.Create(structType)}){{0}};");
+        _writer.WriteLine($"{CType.Create(structType)}_create(&{tmp});");
+
         foreach (var initializer in structInitializerNode.Initializers)
         {
             var value = EmitExpression(initializer.Value);
-            initValues.Add($".{initializer.Key} = {value}");
+            _writer.WriteLine($"{tmp}.{initializer.Key} = {value};");
         }
 
-        var initString = initValues.Count == 0
-            ? "0"
-            : string.Join(", ", initValues);
-
-        return $"({CType.Create(structInitializerNode.Type)}){{{initString}}}";
+        return tmp;
     }
 
     private string EmitI8Literal(I8LiteralNode i8LiteralNode)
@@ -574,17 +647,45 @@ public class Generator
 
     private void EmitBlock(BlockNode blockNode)
     {
-        _deferStack.Push([]);
-
         foreach (var statementNode in blockNode.Statements)
         {
             EmitStatement(statementNode);
         }
+    }
 
-        var blockDefers = _deferStack.Pop();
-        for (var i = blockDefers.Count - 1; i >= 0; i--)
+    private void EmitScopeCleanup()
+    {
+        var deferredStack = Scope.GetDeferred();
+        while (deferredStack.TryPop(out var deferred))
         {
-            EmitStatement(blockDefers[i].Statement);
+            deferred.Invoke();
         }
     }
+
+    private ScopeDisposer BeginScope()
+    {
+        _scopes.Push(new Scope());
+        return new ScopeDisposer(this);
+    }
+
+    private sealed class ScopeDisposer(Generator owner) : IDisposable
+    {
+        public void Dispose()
+        {
+            owner.EmitScopeCleanup();
+            owner._scopes.Pop();
+        }
+    }
+}
+
+public class Scope
+{
+    private readonly List<Action> _deferred = [];
+
+    public void Defer(Action action)
+    {
+        _deferred.Add(action);
+    }
+
+    public Stack<Action> GetDeferred() => new(_deferred);
 }

compiler/NubLang/Generation/HeaderGenerator.cs

@@ -0,0 +1,49 @@
+using NubLang.Ast;
+using NubLang.Syntax;
+
+namespace NubLang.Generation;
+
+public static class HeaderGenerator
+{
+    private static string FuncName(string module, string name, string? externSymbol)
+    {
+        return externSymbol ?? $"{module}_{name}";
+    }
+
+    public static string Generate(string name, TypedModule module)
+    {
+        var writer = new IndentedTextWriter();
+
+        writer.WriteLine();
+
+        foreach (var structType in module.StructTypes)
+        {
+            writer.WriteLine("typedef struct");
+            writer.WriteLine("{");
+            using (writer.Indent())
+            {
+                foreach (var field in structType.Fields)
+                {
+                    writer.WriteLine($"{CType.Create(field.Type)} {field.Name};");
+                }
+            }
+
+            writer.WriteLine($"}} {CType.Create(structType)};");
+            writer.WriteLine($"void {CType.Create(structType)}_create({CType.Create(structType)} *self);");
+            writer.WriteLine($"void {CType.Create(structType)}_destroy({CType.Create(structType)} *self);");
+            writer.WriteLine();
+        }
+
+        foreach (var prototype in module.FunctionPrototypes)
+        {
+            var parameters = prototype.Parameters.Count != 0
+                ? string.Join(", ", prototype.Parameters.Select(x => CType.Create(x.Type, x.NameToken.Value)))
+                : "void";
+
+            var funcName = FuncName(name, prototype.NameToken.Value, prototype.ExternSymbolToken?.Value);
+            writer.WriteLine($"{CType.Create(prototype.ReturnType, funcName)}({parameters});");
+        }
+
+        return writer.ToString();
+    }
+}

compiler/NubLang/Syntax/Module.cs

@@ -7,19 +7,23 @@ public sealed class Module
         var modules = new Dictionary<string, Module>();
         foreach (var syntaxTree in syntaxTrees)
         {
-            if (!modules.TryGetValue(syntaxTree.ModuleName, out var module))
+            var moduleDeclaration = syntaxTree.TopLevelSyntaxNodes.OfType<ModuleSyntax>().FirstOrDefault();
+            if (moduleDeclaration != null)
             {
-                module = new Module();
-                modules.Add(syntaxTree.ModuleName, module);
-            }
+                if (!modules.TryGetValue(moduleDeclaration.NameToken.Value, out var module))
+                {
+                    module = new Module();
+                    modules.Add(moduleDeclaration.NameToken.Value, module);
+                }
 
-            module._definitions.AddRange(syntaxTree.Definitions);
+                module._definitions.AddRange(syntaxTree.TopLevelSyntaxNodes);
+            }
         }
 
         return modules;
     }
 
-    private readonly List<DefinitionSyntax> _definitions = [];
+    private readonly List<TopLevelSyntaxNode> _definitions = [];
 
     public List<StructSyntax> Structs(bool includePrivate)
     {

compiler/NubLang/Syntax/Parser.cs

@@ -19,9 +19,7 @@ public sealed class Parser
         _tokens = tokens;
         _tokenIndex = 0;
 
-        string? moduleName = null;
-        var imports = new List<string>();
-        var definitions = new List<DefinitionSyntax>();
+        var topLevelSyntaxNodes = new List<TopLevelSyntaxNode>();
 
         while (HasToken)
         {
@@ -29,66 +27,34 @@ public sealed class Parser
             {
                 var startIndex = _tokenIndex;
 
-                if (TryExpectSymbol(Symbol.Import))
-                {
-                    var name = ExpectStringLiteral();
-                    if (imports.Contains(name.Value))
-                    {
-                        Diagnostics.Add(Diagnostic
-                            .Warning($"Module {name.Value} is imported twice")
-                            .At(name)
-                            .WithHelp($"Remove duplicate import \"{name.Value}\"")
-                            .Build());
-                    }
-                    else
-                    {
-                        imports.Add(name.Value);
-                    }
-
-                    continue;
-                }
-
-                if (TryExpectSymbol(Symbol.Module))
-                {
-                    if (moduleName != null)
-                    {
-                        throw new ParseException(Diagnostic
-                            .Error("Module is declared more than once")
-                            .At(CurrentToken)
-                            .WithHelp("Remove duplicate module declaration")
-                            .Build());
-                    }
-
-                    moduleName = ExpectStringLiteral().Value;
-                    continue;
-                }
-
                 var exported = TryExpectSymbol(Symbol.Export);
 
                 if (TryExpectSymbol(Symbol.Extern))
                 {
                     var externSymbol = ExpectStringLiteral();
                     ExpectSymbol(Symbol.Func);
-                    definitions.Add(ParseFunc(startIndex, exported, externSymbol.Value));
+                    topLevelSyntaxNodes.Add(ParseFunc(startIndex, exported, externSymbol));
                     continue;
                 }
 
                 var keyword = ExpectSymbol();
-                DefinitionSyntax definition = keyword.Symbol switch
+                TopLevelSyntaxNode definition = keyword.Symbol switch
                 {
+                    Symbol.Module => ParseModule(startIndex),
+                    Symbol.Import => ParseImport(startIndex),
                     Symbol.Func => ParseFunc(startIndex, exported, null),
                     Symbol.Struct => ParseStruct(startIndex, exported),
                     Symbol.Enum => ParseEnum(startIndex, exported),
-                    _ => throw new ParseException(Diagnostic
+                    _ => throw new CompileException(Diagnostic
                         .Error($"Expected 'func', 'struct', 'enum', 'import' or 'module' but found '{keyword.Symbol}'")
                         .WithHelp("Valid top level statements are 'func', 'struct', 'enum', 'import' and 'module'")
                         .At(keyword)
                         .Build())
                 };
 
-                definitions.Add(definition);
+                topLevelSyntaxNodes.Add(definition);
             }
-            catch (ParseException e)
+            catch (CompileException e)
             {
                 Diagnostics.Add(e.Diagnostic);
                 while (HasToken)
@@ -103,7 +69,19 @@ public sealed class Parser
             }
         }
 
-        return new SyntaxTree(definitions, moduleName ?? "default", imports);
+        return new SyntaxTree(topLevelSyntaxNodes);
+    }
+
+    private ImportSyntax ParseImport(int startIndex)
+    {
+        var name = ExpectIdentifier();
+        return new ImportSyntax(GetTokens(startIndex), name);
+    }
+
+    private ModuleSyntax ParseModule(int startIndex)
+    {
+        var name = ExpectIdentifier();
+        return new ModuleSyntax(GetTokens(startIndex), name);
     }
 
     private FuncParameterSyntax ParseFuncParameter()
@@ -113,10 +91,10 @@ public sealed class Parser
         ExpectSymbol(Symbol.Colon);
         var type = ParseType();
 
-        return new FuncParameterSyntax(GetTokens(startIndex), name.Value, type);
+        return new FuncParameterSyntax(GetTokens(startIndex), name, type);
     }
 
-    private FuncSyntax ParseFunc(int startIndex, bool exported, string? externSymbol)
+    private FuncSyntax ParseFunc(int startIndex, bool exported, StringLiteralToken? externSymbol)
     {
         var name = ExpectIdentifier();
         List<FuncParameterSyntax> parameters = [];
@@ -136,7 +114,7 @@ public sealed class Parser
 
         var returnType = TryExpectSymbol(Symbol.Colon) ? ParseType() : new VoidTypeSyntax([]);
 
-        var prototype = new FuncPrototypeSyntax(GetTokens(startIndex), name.Value, exported, externSymbol, parameters, returnType);
+        var prototype = new FuncPrototypeSyntax(GetTokens(startIndex), name, exported, externSymbol, parameters, returnType);
 
         BlockSyntax? body = null;
         var bodyStartIndex = _tokenIndex;
@@ -160,7 +138,7 @@ public sealed class Parser
         {
             var memberStartIndex = _tokenIndex;
 
-            var fieldName = ExpectIdentifier().Value;
+            var fieldName = ExpectIdentifier();
             ExpectSymbol(Symbol.Colon);
             var fieldType = ParseType();
 
@@ -174,7 +152,7 @@ public sealed class Parser
             fields.Add(new StructFieldSyntax(GetTokens(memberStartIndex), fieldName, fieldType, fieldValue));
         }
 
-        return new StructSyntax(GetTokens(startIndex), name.Value, exported, fields);
+        return new StructSyntax(GetTokens(startIndex), name, exported, fields);
     }
 
     private EnumSyntax ParseEnum(int startIndex, bool exported)
@@ -192,37 +170,29 @@ public sealed class Parser
 
         ExpectSymbol(Symbol.OpenBrace);
 
-        long value = -1;
-
         while (!TryExpectSymbol(Symbol.CloseBrace))
         {
             var memberStartIndex = _tokenIndex;
-            var fieldName = ExpectIdentifier().Value;
-            long fieldValue;
+            var fieldName = ExpectIdentifier();
+            IntLiteralToken? value = null;
 
             if (TryExpectSymbol(Symbol.Assign))
             {
                 if (!TryExpectIntLiteral(out var intLiteralToken))
                 {
-                    throw new ParseException(Diagnostic
+                    throw new CompileException(Diagnostic
                         .Error("Value of enum field must be an integer literal")
                         .At(CurrentToken)
                         .Build());
                 }
 
-                fieldValue = Convert.ToInt64(intLiteralToken.Value, intLiteralToken.Base);
-                value = fieldValue;
-            }
-            else
-            {
-                fieldValue = value + 1;
-                value = fieldValue;
+                value = intLiteralToken;
             }
 
-            fields.Add(new EnumFieldSyntax(GetTokens(memberStartIndex), fieldName, fieldValue));
+            fields.Add(new EnumFieldSyntax(GetTokens(memberStartIndex), fieldName, value));
         }
 
-        return new EnumSyntax(GetTokens(startIndex), name.Value, exported, type, fields);
+        return new EnumSyntax(GetTokens(startIndex), name, exported, type, fields);
     }
 
     private StatementSyntax ParseStatement()
@@ -267,7 +237,7 @@ public sealed class Parser
 
     private VariableDeclarationSyntax ParseVariableDeclaration(int startIndex)
     {
-        var name = ExpectIdentifier().Value;
+        var name = ExpectIdentifier();
 
         TypeSyntax? explicitType = null;
         if (TryExpectSymbol(Symbol.Colon))
@@ -334,12 +304,12 @@ public sealed class Parser
 
     private ForSyntax ParseFor(int startIndex)
     {
-        var itemName = ExpectIdentifier().Value;
-        string? indexName = null;
+        var itemName = ExpectIdentifier();
+        IdentifierToken? indexName = null;
 
         if (TryExpectSymbol(Symbol.Comma))
         {
-            indexName = ExpectIdentifier().Value;
+            indexName = ExpectIdentifier();
         }
 
         ExpectSymbol(Symbol.In);
@@ -467,10 +437,10 @@ public sealed class Parser
         var token = ExpectToken();
         var expr = token switch
         {
-            BoolLiteralToken boolLiteral => new BoolLiteralSyntax(GetTokens(startIndex), boolLiteral.Value),
-            StringLiteralToken stringLiteral => new StringLiteralSyntax(GetTokens(startIndex), stringLiteral.Value),
-            FloatLiteralToken floatLiteral => new FloatLiteralSyntax(GetTokens(startIndex), floatLiteral.Value),
-            IntLiteralToken intLiteral => new IntLiteralSyntax(GetTokens(startIndex), intLiteral.Value, intLiteral.Base),
+            BoolLiteralToken boolLiteral => new BoolLiteralSyntax(GetTokens(startIndex), boolLiteral),
+            StringLiteralToken stringLiteral => new StringLiteralSyntax(GetTokens(startIndex), stringLiteral),
+            FloatLiteralToken floatLiteral => new FloatLiteralSyntax(GetTokens(startIndex), floatLiteral),
+            IntLiteralToken intLiteral => new IntLiteralSyntax(GetTokens(startIndex), intLiteral),
             IdentifierToken identifier => ParseIdentifier(startIndex, identifier),
             SymbolToken symbolToken => symbolToken.Symbol switch
             {
@@ -481,13 +451,13 @@ public sealed class Parser
                 Symbol.OpenBrace => new StructInitializerSyntax(GetTokens(startIndex), null, ParseStructInitializerBody()),
                 Symbol.Struct => ParseStructInitializer(startIndex),
                 Symbol.At => ParseBuiltinFunction(startIndex),
-                _ => throw new ParseException(Diagnostic
+                _ => throw new CompileException(Diagnostic
                     .Error($"Unexpected symbol '{symbolToken.Symbol}' in expression")
                     .WithHelp("Expected '(', '-', '!', '[' or '{'")
                     .At(symbolToken)
                     .Build())
             },
-            _ => throw new ParseException(Diagnostic
+            _ => throw new CompileException(Diagnostic
                 .Error($"Unexpected token '{token.GetType().Name}' in expression")
                 .WithHelp("Expected literal, identifier, or parenthesized expression")
                 .At(token)
@@ -518,7 +488,7 @@ public sealed class Parser
             }
             default:
             {
-                throw new ParseException(Diagnostic.Error($"Unknown builtin {name.Value}").At(name).Build());
+                throw new CompileException(Diagnostic.Error($"Unknown builtin {name.Value}").At(name).Build());
             }
         }
     }
@@ -528,10 +498,10 @@ public sealed class Parser
         if (TryExpectSymbol(Symbol.DoubleColon))
         {
             var name = ExpectIdentifier();
-            return new ModuleIdentifierSyntax(GetTokens(startIndex), identifier.Value, name.Value);
+            return new ModuleIdentifierSyntax(GetTokens(startIndex), identifier, name);
         }
 
-        return new LocalIdentifierSyntax(GetTokens(startIndex), identifier.Value);
+        return new LocalIdentifierSyntax(GetTokens(startIndex), identifier);
     }
 
     private ExpressionSyntax ParseParenthesizedExpression()
@@ -560,7 +530,7 @@ public sealed class Parser
 
             if (TryExpectSymbol(Symbol.Period))
             {
-                var member = ExpectIdentifier().Value;
+                var member = ExpectIdentifier();
                 expr = new MemberAccessSyntax(GetTokens(startIndex), expr, member);
                 continue;
             }
@@ -627,12 +597,12 @@ public sealed class Parser
         return new StructInitializerSyntax(GetTokens(startIndex), type, initializers);
     }
 
-    private Dictionary<string, ExpressionSyntax> ParseStructInitializerBody()
+    private Dictionary<IdentifierToken, ExpressionSyntax> ParseStructInitializerBody()
     {
-        Dictionary<string, ExpressionSyntax> initializers = [];
+        Dictionary<IdentifierToken, ExpressionSyntax> initializers = [];
         while (!TryExpectSymbol(Symbol.CloseBrace))
         {
-            var name = ExpectIdentifier().Value;
+            var name = ExpectIdentifier();
             ExpectSymbol(Symbol.Assign);
             var value = ParseExpression();
             initializers.Add(name, value);
@@ -658,7 +628,7 @@ public sealed class Parser
             {
                 statements.Add(ParseStatement());
             }
-            catch (ParseException ex)
+            catch (CompileException ex)
             {
                 Diagnostics.Add(ex.Diagnostic);
                 if (HasToken)
@@ -684,7 +654,7 @@ public sealed class Parser
             {
                 if (size is not 8 and not 16 and not 32 and not 64)
                 {
-                    throw new ParseException(Diagnostic
+                    throw new CompileException(Diagnostic
                         .Error("Arbitrary uint size is not supported")
                         .WithHelp("Use u8, u16, u32 or u64")
                         .At(name)
@@ -698,7 +668,7 @@ public sealed class Parser
             {
                 if (size is not 8 and not 16 and not 32 and not 64)
                 {
-                    throw new ParseException(Diagnostic
+                    throw new CompileException(Diagnostic
                         .Error("Arbitrary int size is not supported")
                         .WithHelp("Use i8, i16, i32 or i64")
                         .At(name)
@@ -712,7 +682,7 @@ public sealed class Parser
             {
                 if (size is not 32 and not 64)
                 {
-                    throw new ParseException(Diagnostic
+                    throw new CompileException(Diagnostic
                         .Error("Arbitrary float size is not supported")
                         .WithHelp("Use f32 or f64")
                         .At(name)
@@ -732,20 +702,26 @@ public sealed class Parser
                     return new BoolTypeSyntax(GetTokens(startIndex));
                 default:
                 {
-                    string? module = null;
+                    IdentifierToken? module = null;
 
                     if (TryExpectSymbol(Symbol.DoubleColon))
                     {
                         var customTypeName = ExpectIdentifier();
-                        module = name.Value;
+                        module = name;
                         name = customTypeName;
                     }
 
-                    return new CustomTypeSyntax(GetTokens(startIndex), module, name.Value);
+                    return new CustomTypeSyntax(GetTokens(startIndex), module, name);
                 }
             }
         }
 
+        if (TryExpectSymbol(Symbol.Ampersand))
+        {
+            var baseType = ParseType();
+            return new RefTypeSyntax(GetTokens(startIndex), baseType);
+        }
+
         if (TryExpectSymbol(Symbol.Caret))
         {
             var baseType = ParseType();
@@ -780,7 +756,7 @@ public sealed class Parser
             {
                 ExpectSymbol(Symbol.CloseBracket);
                 var baseType = ParseType();
-                return new ConstArrayTypeSyntax(GetTokens(startIndex), baseType, Convert.ToInt64(intLiteral.Value, intLiteral.Base));
+                return new ConstArrayTypeSyntax(GetTokens(startIndex), baseType, intLiteral.AsU64);
             }
             else if (TryExpectSymbol(Symbol.QuestionMark))
             {
@@ -796,7 +772,7 @@ public sealed class Parser
             }
         }
 
-        throw new ParseException(Diagnostic
+        throw new CompileException(Diagnostic
             .Error("Invalid type syntax")
             .WithHelp("Expected type name, '^' for pointer, or '[]' for array")
             .At(CurrentToken)
@@ -807,7 +783,7 @@ public sealed class Parser
     {
         if (!HasToken)
         {
-            throw new ParseException(Diagnostic
+            throw new CompileException(Diagnostic
                 .Error("Unexpected end of file")
                 .WithHelp("Expected more tokens to complete the syntax")
                 .At(_tokens[^1])
@@ -824,7 +800,7 @@ public sealed class Parser
         var token = ExpectToken();
         if (token is not SymbolToken symbol)
         {
-            throw new ParseException(Diagnostic
+            throw new CompileException(Diagnostic
                 .Error($"Expected symbol, but found {token.GetType().Name}")
                 .WithHelp("This position requires a symbol like '(', ')', '{', '}', etc.")
                 .At(token)
@@ -839,7 +815,7 @@ public sealed class Parser
         var token = ExpectSymbol();
         if (token.Symbol != expectedSymbol)
         {
-            throw new ParseException(Diagnostic
+            throw new CompileException(Diagnostic
                 .Error($"Expected '{expectedSymbol}', but found '{token.Symbol}'")
                 .WithHelp($"Insert '{expectedSymbol}' here")
                 .At(token)
@@ -889,7 +865,7 @@ public sealed class Parser
         var token = ExpectToken();
         if (token is not IdentifierToken identifier)
         {
-            throw new ParseException(Diagnostic
+            throw new CompileException(Diagnostic
                 .Error($"Expected identifier, but found {token.GetType().Name}")
                 .WithHelp("Provide a valid identifier name here")
                 .At(token)
@@ -917,7 +893,7 @@ public sealed class Parser
         var token = ExpectToken();
         if (token is not StringLiteralToken identifier)
         {
-            throw new ParseException(Diagnostic
+            throw new CompileException(Diagnostic
                 .Error($"Expected string literal, but found {token.GetType().Name}")
                 .WithHelp("Provide a valid string literal")
                 .At(token)
@@ -938,14 +914,4 @@ public sealed class Parser
     }
 }
 
-public record SyntaxTree(List<DefinitionSyntax> Definitions, string ModuleName, List<string> Imports);
-
-public class ParseException : Exception
-{
-    public Diagnostic Diagnostic { get; }
-
-    public ParseException(Diagnostic diagnostic) : base(diagnostic.Message)
-    {
-        Diagnostic = diagnostic;
-    }
-}
+public record SyntaxTree(List<TopLevelSyntaxNode> TopLevelSyntaxNodes);

compiler/NubLang/Syntax/Syntax.cs

@@ -4,21 +4,27 @@ public abstract record SyntaxNode(List<Token> Tokens);
 
 #region Definitions
 
-public abstract record DefinitionSyntax(List<Token> Tokens, string Name, bool Exported) : SyntaxNode(Tokens);
+public record TopLevelSyntaxNode(List<Token> Tokens) : SyntaxNode(Tokens);
 
-public record FuncParameterSyntax(List<Token> Tokens, string Name, TypeSyntax Type) : SyntaxNode(Tokens);
+public record ModuleSyntax(List<Token> Tokens, IdentifierToken NameToken) : TopLevelSyntaxNode(Tokens);
 
-public record FuncPrototypeSyntax(List<Token> Tokens, string Name, bool Exported, string? ExternSymbol, List<FuncParameterSyntax> Parameters, TypeSyntax ReturnType) : SyntaxNode(Tokens);
+public record ImportSyntax(List<Token> Tokens, IdentifierToken NameToken) : TopLevelSyntaxNode(Tokens);
 
-public record FuncSyntax(List<Token> Tokens, FuncPrototypeSyntax Prototype, BlockSyntax? Body) : DefinitionSyntax(Tokens, Prototype.Name, Prototype.Exported);
+public abstract record DefinitionSyntax(List<Token> Tokens, IdentifierToken NameToken, bool Exported) : TopLevelSyntaxNode(Tokens);
 
-public record StructFieldSyntax(List<Token> Tokens, string Name, TypeSyntax Type, ExpressionSyntax? Value) : SyntaxNode(Tokens);
+public record FuncParameterSyntax(List<Token> Tokens, IdentifierToken NameToken, TypeSyntax Type) : SyntaxNode(Tokens);
 
-public record StructSyntax(List<Token> Tokens, string Name, bool Exported, List<StructFieldSyntax> Fields) : DefinitionSyntax(Tokens, Name, Exported);
+public record FuncPrototypeSyntax(List<Token> Tokens, IdentifierToken NameToken, bool Exported, StringLiteralToken? ExternSymbolToken, List<FuncParameterSyntax> Parameters, TypeSyntax ReturnType) : SyntaxNode(Tokens);
 
-public record EnumFieldSyntax(List<Token> Tokens, string Name, long Value) : SyntaxNode(Tokens);
+public record FuncSyntax(List<Token> Tokens, FuncPrototypeSyntax Prototype, BlockSyntax? Body) : DefinitionSyntax(Tokens, Prototype.NameToken, Prototype.Exported);
 
-public record EnumSyntax(List<Token> Tokens, string Name, bool Exported, TypeSyntax? Type, List<EnumFieldSyntax> Fields) : DefinitionSyntax(Tokens, Name, Exported);
+public record StructFieldSyntax(List<Token> Tokens, IdentifierToken NameToken, TypeSyntax Type, ExpressionSyntax? Value) : SyntaxNode(Tokens);
+
+public record StructSyntax(List<Token> Tokens, IdentifierToken NameToken, bool Exported, List<StructFieldSyntax> Fields) : DefinitionSyntax(Tokens, NameToken, Exported);
+
+public record EnumFieldSyntax(List<Token> Tokens, IdentifierToken NameToken, IntLiteralToken? ValueToken) : SyntaxNode(Tokens);
+
+public record EnumSyntax(List<Token> Tokens, IdentifierToken NameToken, bool Exported, TypeSyntax? Type, List<EnumFieldSyntax> Fields) : DefinitionSyntax(Tokens, NameToken, Exported);
 
 public enum UnaryOperatorSyntax
 {
@@ -64,7 +70,7 @@ public record AssignmentSyntax(List<Token> Tokens, ExpressionSyntax Target, Expr
 
 public record IfSyntax(List<Token> Tokens, ExpressionSyntax Condition, BlockSyntax Body, Variant<IfSyntax, BlockSyntax>? Else) : StatementSyntax(Tokens);
 
-public record VariableDeclarationSyntax(List<Token> Tokens, string Name, TypeSyntax? ExplicitType, ExpressionSyntax? Assignment) : StatementSyntax(Tokens);
+public record VariableDeclarationSyntax(List<Token> Tokens, IdentifierToken NameToken, TypeSyntax? ExplicitType, ExpressionSyntax? Assignment) : StatementSyntax(Tokens);
 
 public record ContinueSyntax(List<Token> Tokens) : StatementSyntax(Tokens);
 
@@ -74,7 +80,7 @@ public record DeferSyntax(List<Token> Tokens, StatementSyntax Statement) : State
 
 public record WhileSyntax(List<Token> Tokens, ExpressionSyntax Condition, BlockSyntax Body) : StatementSyntax(Tokens);
 
-public record ForSyntax(List<Token> Tokens, string ElementName, string? IndexName, ExpressionSyntax Target, BlockSyntax Body) : StatementSyntax(Tokens);
+public record ForSyntax(List<Token> Tokens, IdentifierToken ElementNameToken, IdentifierToken? IndexNameToken, ExpressionSyntax Target, BlockSyntax Body) : StatementSyntax(Tokens);
 
 #endregion
 
@@ -88,9 +94,9 @@ public record UnaryExpressionSyntax(List<Token> Tokens, UnaryOperatorSyntax Oper
 
 public record FuncCallSyntax(List<Token> Tokens, ExpressionSyntax Expression, List<ExpressionSyntax> Parameters) : ExpressionSyntax(Tokens);
 
-public record LocalIdentifierSyntax(List<Token> Tokens, string Name) : ExpressionSyntax(Tokens);
+public record LocalIdentifierSyntax(List<Token> Tokens, IdentifierToken NameToken) : ExpressionSyntax(Tokens);
 
-public record ModuleIdentifierSyntax(List<Token> Tokens, string Module, string Name) : ExpressionSyntax(Tokens);
+public record ModuleIdentifierSyntax(List<Token> Tokens, IdentifierToken ModuleToken, IdentifierToken NameToken) : ExpressionSyntax(Tokens);
 
 public record ArrayInitializerSyntax(List<Token> Tokens, List<ExpressionSyntax> Values) : ExpressionSyntax(Tokens);
 
@@ -98,17 +104,17 @@ public record ArrayIndexAccessSyntax(List<Token> Tokens, ExpressionSyntax Target
 
 public record AddressOfSyntax(List<Token> Tokens, ExpressionSyntax Target) : ExpressionSyntax(Tokens);
 
-public record IntLiteralSyntax(List<Token> Tokens, string Value, int Base) : ExpressionSyntax(Tokens);
+public record IntLiteralSyntax(List<Token> Tokens, IntLiteralToken Token) : ExpressionSyntax(Tokens);
 
-public record StringLiteralSyntax(List<Token> Tokens, string Value) : ExpressionSyntax(Tokens);
+public record StringLiteralSyntax(List<Token> Tokens, StringLiteralToken Token) : ExpressionSyntax(Tokens);
 
-public record BoolLiteralSyntax(List<Token> Tokens, bool Value) : ExpressionSyntax(Tokens);
+public record BoolLiteralSyntax(List<Token> Tokens, BoolLiteralToken Token) : ExpressionSyntax(Tokens);
 
-public record FloatLiteralSyntax(List<Token> Tokens, string Value) : ExpressionSyntax(Tokens);
+public record FloatLiteralSyntax(List<Token> Tokens, FloatLiteralToken Token) : ExpressionSyntax(Tokens);
 
-public record MemberAccessSyntax(List<Token> Tokens, ExpressionSyntax Target, string Member) : ExpressionSyntax(Tokens);
+public record MemberAccessSyntax(List<Token> Tokens, ExpressionSyntax Target, IdentifierToken MemberToken) : ExpressionSyntax(Tokens);
 
-public record StructInitializerSyntax(List<Token> Tokens, TypeSyntax? StructType, Dictionary<string, ExpressionSyntax> Initializers) : ExpressionSyntax(Tokens);
+public record StructInitializerSyntax(List<Token> Tokens, TypeSyntax? StructType, Dictionary<IdentifierToken, ExpressionSyntax> Initializers) : ExpressionSyntax(Tokens);
 
 public record DereferenceSyntax(List<Token> Tokens, ExpressionSyntax Target) : ExpressionSyntax(Tokens);
 
@@ -140,8 +146,10 @@ public record SliceTypeSyntax(List<Token> Tokens, TypeSyntax BaseType) : TypeSyn
 
 public record ArrayTypeSyntax(List<Token> Tokens, TypeSyntax BaseType) : TypeSyntax(Tokens);
 
-public record ConstArrayTypeSyntax(List<Token> Tokens, TypeSyntax BaseType, long Size) : TypeSyntax(Tokens);
+public record ConstArrayTypeSyntax(List<Token> Tokens, TypeSyntax BaseType, ulong Size) : TypeSyntax(Tokens);
 
-public record CustomTypeSyntax(List<Token> Tokens, string? Module, string Name) : TypeSyntax(Tokens);
+public record CustomTypeSyntax(List<Token> Tokens, IdentifierToken? ModuleToken, IdentifierToken NameToken) : TypeSyntax(Tokens);
+
+public record RefTypeSyntax(List<Token> Tokens, TypeSyntax BaseType) : TypeSyntax(Tokens);
 
 #endregion

compiler/NubLang/Syntax/Token.cs

@@ -2,8 +2,68 @@
 
 namespace NubLang.Syntax;
 
+public abstract record Token(SourceSpan Span);
+
+public record IdentifierToken(SourceSpan Span, string Value) : Token(Span)
+{
+    public override string ToString()
+    {
+        return Value;
+    }
+}
+
+public record IntLiteralToken(SourceSpan Span, string Value, int Base) : Token(Span)
+{
+    public ulong AsU64 => Convert.ToUInt64(Value, Base);
+    public long AsI64 => Convert.ToInt64(Value, Base);
+    public uint AsU32 => Convert.ToUInt32(Value, Base);
+    public int AsI32 => Convert.ToInt32(Value, Base);
+    public ushort AsU16 => Convert.ToUInt16(Value, Base);
+    public short AsI16 => Convert.ToInt16(Value, Base);
+    public byte AsU8 => Convert.ToByte(Value, Base);
+    public sbyte AsI8 => Convert.ToSByte(Value, Base);
+
+    public float AsF32 => Convert.ToSingle(AsI32);
+    public double AsF64 => Convert.ToDouble(AsI64);
+
+    public override string ToString()
+    {
+        return Value;
+    }
+}
+
+public record StringLiteralToken(SourceSpan Span, string Value) : Token(Span)
+{
+    public override string ToString()
+    {
+        return $"\"{Value}\"";
+    }
+}
+
+public record BoolLiteralToken(SourceSpan Span, bool Value) : Token(Span)
+{
+    public override string ToString()
+    {
+        return Value ? "true" : "false";
+    }
+}
+
+public record FloatLiteralToken(SourceSpan Span, string Value) : Token(Span)
+{
+    public float AsF32 => Convert.ToSingle(Value);
+    public double AsF64 => Convert.ToDouble(Value);
+
+    public override string ToString()
+    {
+        return Value;
+    }
+}
+
 public enum Symbol
 {
+    // Default
+    None,
+
     // Control
     If,
     Else,
@@ -62,16 +122,63 @@ public enum Symbol
     QuestionMark,
 }
 
-public abstract record Token(SourceSpan Span);
-
-public record IdentifierToken(SourceSpan Span, string Value) : Token(Span);
-
-public record IntLiteralToken(SourceSpan Span, string Value, int Base) : Token(Span);
-
-public record StringLiteralToken(SourceSpan Span, string Value) : Token(Span);
-
-public record BoolLiteralToken(SourceSpan Span, bool Value) : Token(Span);
-
-public record FloatLiteralToken(SourceSpan Span, string Value) : Token(Span);
-
-public record SymbolToken(SourceSpan Span, Symbol Symbol) : Token(Span);
+public record SymbolToken(SourceSpan Span, Symbol Symbol) : Token(Span)
+{
+    public override string ToString()
+    {
+        return Symbol switch
+        {
+            Symbol.Func => "func",
+            Symbol.If => "if",
+            Symbol.Else => "else",
+            Symbol.While => "while",
+            Symbol.For => "for",
+            Symbol.In => "in",
+            Symbol.Break => "break",
+            Symbol.Continue => "continue",
+            Symbol.Return => "return",
+            Symbol.Struct => "struct",
+            Symbol.Let => "let",
+            Symbol.Extern => "extern",
+            Symbol.Module => "module",
+            Symbol.Export => "export",
+            Symbol.Import => "import",
+            Symbol.Defer => "defer",
+            Symbol.Enum => "enum",
+            Symbol.Equal => "==",
+            Symbol.NotEqual => "!=",
+            Symbol.LessThanOrEqual => "<=",
+            Symbol.GreaterThanOrEqual => ">=",
+            Symbol.LeftShift => "<<",
+            Symbol.RightShift => ">>",
+            Symbol.And => "&&",
+            Symbol.Or => "||",
+            Symbol.DoubleColon => "::",
+            Symbol.Colon => ":",
+            Symbol.OpenParen => "(",
+            Symbol.CloseParen => ")",
+            Symbol.OpenBrace => "{",
+            Symbol.CloseBrace => "}",
+            Symbol.OpenBracket => "[",
+            Symbol.CloseBracket => "]",
+            Symbol.Comma => ",",
+            Symbol.Period => ".",
+            Symbol.Assign => "=",
+            Symbol.LessThan => "<",
+            Symbol.GreaterThan => ">",
+            Symbol.Plus => "+",
+            Symbol.Minus => "-",
+            Symbol.Star => "*",
+            Symbol.ForwardSlash => "/",
+            Symbol.Bang => "!",
+            Symbol.Caret => "^",
+            Symbol.Ampersand => "&",
+            Symbol.Semi => ";",
+            Symbol.Percent => "%",
+            Symbol.Pipe => "|",
+            Symbol.At => "@",
+            Symbol.QuestionMark => "?",
+            _ => "none",
+        };
+    }
+}

compiler/NubLang/Syntax/Tokenizer.cs

@@ -4,72 +4,9 @@ namespace NubLang.Syntax;
 
 public sealed class Tokenizer
 {
-    private static readonly Dictionary<string, Symbol> Keywords = new()
-    {
-        ["func"] = Symbol.Func,
-        ["if"] = Symbol.If,
-        ["else"] = Symbol.Else,
-        ["while"] = Symbol.While,
-        ["for"] = Symbol.For,
-        ["in"] = Symbol.In,
-        ["break"] = Symbol.Break,
-        ["continue"] = Symbol.Continue,
-        ["return"] = Symbol.Return,
-        ["struct"] = Symbol.Struct,
-        ["let"] = Symbol.Let,
-        ["extern"] = Symbol.Extern,
-        ["module"] = Symbol.Module,
-        ["export"] = Symbol.Export,
-        ["import"] = Symbol.Import,
-        ["defer"] = Symbol.Defer,
-        ["enum"] = Symbol.Enum,
-    };
-
-    private static readonly Dictionary<char[], Symbol> Symbols = new()
-    {
-        [['=', '=']] = Symbol.Equal,
-        [['!', '=']] = Symbol.NotEqual,
-        [['<', '=']] = Symbol.LessThanOrEqual,
-        [['>', '=']] = Symbol.GreaterThanOrEqual,
-        [['<', '<']] = Symbol.LeftShift,
-        [['>', '>']] = Symbol.RightShift,
-        [['&', '&']] = Symbol.And,
-        [['|', '|']] = Symbol.Or,
-        [[':', ':']] = Symbol.DoubleColon,
-        [[':']] = Symbol.Colon,
-        [['(']] = Symbol.OpenParen,
-        [[')']] = Symbol.CloseParen,
-        [['{']] = Symbol.OpenBrace,
-        [['}']] = Symbol.CloseBrace,
-        [['[']] = Symbol.OpenBracket,
-        [[']']] = Symbol.CloseBracket,
-        [[',']] = Symbol.Comma,
-        [['.']] = Symbol.Period,
-        [['=']] = Symbol.Assign,
-        [['<']] = Symbol.LessThan,
-        [['>']] = Symbol.GreaterThan,
-        [['+']] = Symbol.Plus,
-        [['-']] = Symbol.Minus,
-        [['*']] = Symbol.Star,
-        [['/']] = Symbol.ForwardSlash,
-        [['!']] = Symbol.Bang,
-        [['^']] = Symbol.Caret,
-        [['&']] = Symbol.Ampersand,
-        [[';']] = Symbol.Semi,
-        [['%']] = Symbol.Percent,
-        [['|']] = Symbol.Pipe,
-        [['@']] = Symbol.At,
-        [['?']] = Symbol.QuestionMark,
-    };
-
-    private static readonly (char[] Pattern, Symbol Symbol)[] OrderedSymbols = Symbols
-        .OrderByDescending(kvp => kvp.Key.Length)
-        .Select(kvp => (kvp.Key, kvp.Value))
-        .ToArray();
-
     private readonly string _fileName;
     private readonly string _content;
-    private int _index = 0;
+    private int _index;
     private int _line = 1;
     private int _column = 1;
 
@@ -79,8 +16,8 @@ public sealed class Tokenizer
         _content = content;
     }
 
-    public List<Diagnostic> Diagnostics { get; } = [];
-    public List<Token> Tokens { get; } = [];
+    public List<Diagnostic> Diagnostics { get; } = new(16);
+    public List<Token> Tokens { get; } = new(256);
 
     public void Tokenize()
     {
@@ -90,17 +27,17 @@ public sealed class Tokenizer
         _line = 1;
         _column = 1;
 
-        while (Peek().HasValue)
+        while (_index < _content.Length)
         {
             try
             {
-                var current = Peek()!.Value;
+                var current = _content[_index];
+
                 if (char.IsWhiteSpace(current))
                 {
-                    if (current is '\n')
+                    if (current == '\n')
                     {
                         _line += 1;
-                        // note(nub31): Next increments the column, so 0 is correct here
                         _column = 0;
                     }
 
@@ -108,10 +45,10 @@ public sealed class Tokenizer
                     continue;
                 }
 
-                if (current == '/' && Peek(1) == '/')
+                if (current == '/' && _index + 1 < _content.Length && _content[_index + 1] == '/')
                 {
-                    // note(nub31): Keep newline so next iteration increments the line counter
-                    while (Peek() is not '\n')
+                    Next(2);
+                    while (_index < _content.Length && _content[_index] != '\n')
                     {
                         Next();
                     }
@@ -121,7 +58,7 @@ public sealed class Tokenizer
 
                 Tokens.Add(ParseToken(current, _line, _column));
             }
-            catch (TokenizerException e)
+            catch (CompileException e)
             {
                 Diagnostics.Add(e.Diagnostic);
                 Next();
@@ -131,171 +68,301 @@ public sealed class Tokenizer
 
     private Token ParseToken(char current, int lineStart, int columnStart)
     {
-        if (char.IsLetter(current) || current == '_')
-        {
-            var buffer = string.Empty;
-
-            while (Peek() != null && (char.IsLetterOrDigit(Peek()!.Value) || Peek() == '_'))
-            {
-                buffer += Peek();
-                Next();
-            }
-
-            if (Keywords.TryGetValue(buffer, out var keywordSymbol))
-            {
-                return new SymbolToken(CreateSpan(lineStart, columnStart), keywordSymbol);
-            }
-
-            if (buffer is "true" or "false")
-            {
-                return new BoolLiteralToken(CreateSpan(lineStart, columnStart), Convert.ToBoolean(buffer));
-            }
-
-            return new IdentifierToken(CreateSpan(lineStart, columnStart), buffer);
-        }
-
+        // Numbers
         if (char.IsDigit(current))
         {
-            var buffer = string.Empty;
+            return ParseNumber(lineStart, columnStart);
+        }
 
-            if (current == '0' && Peek(1) is 'x')
+        // String literals
+        if (current == '"')
+        {
+            return ParseString(lineStart, columnStart);
+        }
+
+        // Try keywords and symbols by length (longest first)
+        for (var i = 8; i >= 1; i--)
+        {
+            if (TryMatchSymbol(i, lineStart, columnStart, out var token))
             {
-                buffer += "0x";
-                Next();
-                Next();
-                while (Peek() != null && Uri.IsHexDigit(Peek()!.Value))
-                {
-                    buffer += Peek()!.Value;
-                    Next();
-                }
+                return token;
+            }
+        }
 
-                if (buffer.Length <= 2)
+        // Identifiers
+        if (char.IsLetter(current) || current == '_')
+        {
+            return ParseIdentifier(lineStart, columnStart);
+        }
+
+        throw new CompileException(Diagnostic.Error($"Unknown token '{current}'").Build());
+    }
+
+    private Token ParseNumber(int lineStart, int columnStart)
+    {
+        var start = _index;
+        var current = _content[_index];
+
+        // Hex literal
+        if (current == '0' && _index + 1 < _content.Length && _content[_index + 1] == 'x')
+        {
+            Next(2);
+            var digitStart = _index;
+
+            while (_index < _content.Length && Uri.IsHexDigit(_content[_index]))
+            {
+                Next();
+            }
+
+            if (_index == digitStart)
+            {
+                throw new CompileException(Diagnostic
+                    .Error("Invalid hex literal, no digits found")
+                    .At(_fileName, _line, _column)
+                    .Build());
+            }
+
+            return new IntLiteralToken(
+                CreateSpan(lineStart, columnStart),
+                _content.Substring(start, _index - start),
+                16);
+        }
+
+        // Binary literal
+        if (current == '0' && _index + 1 < _content.Length && _content[_index + 1] == 'b')
+        {
+            Next(2);
+            var digitStart = _index;
+
+            while (_index < _content.Length && (_content[_index] == '0' || _content[_index] == '1'))
+            {
+                Next();
+            }
+
+            if (_index == digitStart)
+            {
+                throw new CompileException(Diagnostic
+                    .Error("Invalid binary literal, no digits found")
+                    .At(_fileName, _line, _column)
+                    .Build());
+            }
+
+            return new IntLiteralToken(
+                CreateSpan(lineStart, columnStart),
+                _content.Substring(start, _index - start),
+                2);
+        }
+
+        // Decimal or float
+        var isFloat = false;
+        while (_index < _content.Length)
+        {
+            var next = _content[_index];
+
+            if (next == '.')
+            {
+                if (isFloat)
                 {
-                    throw new TokenizerException(Diagnostic
-                        .Error("Invalid hex literal, no digits found")
+                    throw new CompileException(Diagnostic
+                        .Error("More than one period found in float literal")
                         .At(_fileName, _line, _column)
                         .Build());
                 }
 
-                return new IntLiteralToken(CreateSpan(lineStart, columnStart), buffer, 16);
-            }
-
-            if (current == '0' && Peek(1) is 'b')
-            {
-                buffer += "0b";
+                isFloat = true;
                 Next();
+            }
+            else if (char.IsDigit(next))
+            {
                 Next();
-                while (Peek() != null && (Peek() == '0' || Peek() == '1'))
-                {
-                    buffer += Peek()!.Value;
-                    Next();
-                }
-
-                if (buffer.Length <= 2)
-                {
-                    throw new TokenizerException(Diagnostic
-                        .Error("Invalid binary literal, no digits found")
-                        .At(_fileName, _line, _column)
-                        .Build());
-                }
-
-                return new IntLiteralToken(CreateSpan(lineStart, columnStart), buffer, 2);
-            }
-
-            var isFloat = false;
-            while (Peek() != null)
-            {
-                var next = Peek()!.Value;
-                if (next == '.')
-                {
-                    if (isFloat)
-                    {
-                        throw new TokenizerException(Diagnostic
-                            .Error("More than one period found in float literal")
-                            .At(_fileName, _line, _column)
-                            .Build());
-                    }
-
-                    isFloat = true;
-                    buffer += next;
-                    Next();
-                }
-                else if (char.IsDigit(next))
-                {
-                    buffer += next;
-                    Next();
-                }
-                else
-                {
-                    break;
-                }
-            }
-
-            if (isFloat)
-            {
-                return new FloatLiteralToken(CreateSpan(lineStart, columnStart), buffer);
             }
             else
             {
-                return new IntLiteralToken(CreateSpan(lineStart, columnStart), buffer, 10);
+                break;
             }
         }
 
-        if (current == '"')
+        var buffer = _content.Substring(start, _index - start);
+
+        return isFloat
+            ? new FloatLiteralToken(CreateSpan(lineStart, columnStart), buffer)
+            : new IntLiteralToken(CreateSpan(lineStart, columnStart), buffer, 10);
+    }
+
+    private StringLiteralToken ParseString(int lineStart, int columnStart)
+    {
+        Next(); // Skip opening quote
+        var start = _index;
+
+        while (true)
         {
-            Next();
-            var buffer = string.Empty;
-
-            while (true)
+            if (_index >= _content.Length)
             {
-                var next = Peek();
-                if (!next.HasValue)
-                {
-                    throw new TokenizerException(Diagnostic
-                        .Error("Unclosed string literal")
-                        .At(_fileName, _line, _column)
-                        .Build());
-                }
+                throw new CompileException(Diagnostic
+                    .Error("Unclosed string literal")
+                    .At(_fileName, _line, _column)
+                    .Build());
+            }
 
-                if (next is '\n')
-                {
-                    _line += 1;
-                    break;
-                }
+            var next = _content[_index];
 
-                if (next is '"')
-                {
-                    Next();
-                    break;
-                }
+            if (next == '\n')
+            {
+                throw new CompileException(Diagnostic
+                    .Error("Unclosed string literal (newline found)")
+                    .At(_fileName, _line, _column)
+                    .Build());
+            }
 
-                buffer += next;
+            if (next == '"')
+            {
+                var buffer = _content.Substring(start, _index - start);
+                Next();
+                return new StringLiteralToken(CreateSpan(lineStart, columnStart), buffer);
+            }
+
+            Next();
+        }
+    }
+
+    private bool TryMatchSymbol(int length, int lineStart, int columnStart, out Token token)
+    {
+        token = null!;
+
+        if (_index + length > _content.Length)
+        {
+            return false;
+        }
+
+        var span = _content.AsSpan(_index, length);
+
+        var symbol = length switch
+        {
+            8 => span switch
+            {
+                "continue" => Symbol.Continue,
+                _ => Symbol.None
+            },
+            6 => span switch
+            {
+                "return" => Symbol.Return,
+                "struct" => Symbol.Struct,
+                "extern" => Symbol.Extern,
+                "module" => Symbol.Module,
+                "export" => Symbol.Export,
+                "import" => Symbol.Import,
+                _ => Symbol.None
+            },
+            5 => span switch
+            {
+                "break" => Symbol.Break,
+                "while" => Symbol.While,
+                "defer" => Symbol.Defer,
+                _ => Symbol.None
+            },
+            4 => span switch
+            {
+                "func" => Symbol.Func,
+                "else" => Symbol.Else,
+                "enum" => Symbol.Enum,
+                _ => Symbol.None
+            },
+            3 => span switch
+            {
+                "for" => Symbol.For,
+                "let" => Symbol.Let,
+                _ => Symbol.None
+            },
+            2 => span switch
+            {
+                "if" => Symbol.If,
+                "in" => Symbol.In,
+                "==" => Symbol.Equal,
+                "!=" => Symbol.NotEqual,
+                "<=" => Symbol.LessThanOrEqual,
+                ">=" => Symbol.GreaterThanOrEqual,
+                "<<" => Symbol.LeftShift,
+                ">>" => Symbol.RightShift,
+                "&&" => Symbol.And,
+                "||" => Symbol.Or,
+                "::" => Symbol.DoubleColon,
+                _ => Symbol.None
+            },
+            1 => span[0] switch
+            {
+                ':' => Symbol.Colon,
+                '(' => Symbol.OpenParen,
+                ')' => Symbol.CloseParen,
+                '{' => Symbol.OpenBrace,
+                '}' => Symbol.CloseBrace,
+                '[' => Symbol.OpenBracket,
+                ']' => Symbol.CloseBracket,
+                ',' => Symbol.Comma,
+                '.' => Symbol.Period,
+                '=' => Symbol.Assign,
+                '<' => Symbol.LessThan,
+                '>' => Symbol.GreaterThan,
+                '+' => Symbol.Plus,
+                '-' => Symbol.Minus,
+                '*' => Symbol.Star,
+                '/' => Symbol.ForwardSlash,
+                '!' => Symbol.Bang,
+                '^' => Symbol.Caret,
+                '&' => Symbol.Ampersand,
+                ';' => Symbol.Semi,
+                '%' => Symbol.Percent,
+                '|' => Symbol.Pipe,
+                '@' => Symbol.At,
+                '?' => Symbol.QuestionMark,
+                _ => Symbol.None
+            },
+            _ => Symbol.None
+        };
+
+        if (symbol != Symbol.None)
+        {
+            var isAlphaKeyword = char.IsLetter(span[0]);
+            if (isAlphaKeyword)
+            {
+                var nextIdx = _index + length;
+                if (nextIdx < _content.Length)
+                {
+                    var nextChar = _content[nextIdx];
+                    if (char.IsLetterOrDigit(nextChar) || nextChar == '_')
+                    {
+                        return false;
+                    }
+                }
+            }
+
+            Next(length);
+            token = new SymbolToken(CreateSpan(lineStart, columnStart), symbol);
+            return true;
+        }
+
+        return false;
+    }
+
+    private IdentifierToken ParseIdentifier(int lineStart, int columnStart)
+    {
+        var start = _index;
+
+        while (_index < _content.Length)
+        {
+            var ch = _content[_index];
+            if (char.IsLetterOrDigit(ch) || ch == '_')
+            {
                 Next();
             }
-
-            return new StringLiteralToken(CreateSpan(lineStart, columnStart), buffer);
-        }
-
-        foreach (var (pattern, symbol) in OrderedSymbols)
-        {
-            for (var i = 0; i < pattern.Length; i++)
+            else
             {
-                var c = Peek(i);
-                if (!c.HasValue || c.Value != pattern[i]) break;
-
-                if (i == pattern.Length - 1)
-                {
-                    for (var j = 0; j <= i; j++)
-                    {
-                        Next();
-                    }
-
-                    return new SymbolToken(CreateSpan(lineStart, columnStart), symbol);
-                }
+                break;
             }
         }
 
-        throw new TokenizerException(Diagnostic.Error($"Unknown token '{current}'").Build());
+        return new IdentifierToken(
+            CreateSpan(lineStart, columnStart),
+            _content.Substring(start, _index - start));
     }
 
     private SourceSpan CreateSpan(int lineStart, int columnStart)
@@ -303,29 +370,9 @@ public sealed class Tokenizer
         return new SourceSpan(_fileName, new SourceLocation(lineStart, columnStart), new SourceLocation(_line, _column));
     }
 
-    private char? Peek(int offset = 0)
+    private void Next(int count = 1)
     {
-        if (_index + offset < _content.Length)
-        {
-            return _content[_index + offset];
-        }
-
-        return null;
-    }
-
-    private void Next()
-    {
-        _index += 1;
-        _column += 1;
-    }
-}
-
-public class TokenizerException : Exception
-{
-    public Diagnostic Diagnostic { get; }
-
-    public TokenizerException(Diagnostic diagnostic) : base(diagnostic.Message)
-    {
-        Diagnostic = diagnostic;
+        _index += count;
+        _column += count;
     }
 }

compiler/NubLang/Syntax/TypedModule.cs

@@ -0,0 +1,50 @@
+using NubLang.Ast;
+
+namespace NubLang.Syntax;
+
+public sealed class TypedModule
+{
+    public static TypedModule FromModule(string name, Module module, Dictionary<string, Module> modules)
+    {
+        var typeResolver = new TypeResolver(modules);
+
+        var functionPrototypes = new List<FuncPrototypeNode>();
+
+        foreach (var funcSyntax in module.Functions(true))
+        {
+            var parameters = new List<FuncParameterNode>();
+            foreach (var parameter in funcSyntax.Prototype.Parameters)
+            {
+                parameters.Add(new FuncParameterNode(parameter.Tokens, parameter.NameToken, typeResolver.ResolveType(parameter.Type, name)));
+            }
+
+            var returnType = typeResolver.ResolveType(funcSyntax.Prototype.ReturnType, name);
+
+            functionPrototypes.Add(new FuncPrototypeNode(funcSyntax.Tokens, funcSyntax.Prototype.NameToken, funcSyntax.Prototype.ExternSymbolToken, parameters, returnType));
+        }
+
+        var structTypes = new List<NubStructType>();
+
+        foreach (var structSyntax in module.Structs(true))
+        {
+            var fields = new List<NubStructFieldType>();
+            foreach (var field in structSyntax.Fields)
+            {
+                fields.Add(new NubStructFieldType(field.NameToken.Value, typeResolver.ResolveType(field.Type, name), field.Value != null));
+            }
+
+            structTypes.Add(new NubStructType(name, structSyntax.NameToken.Value, fields));
+        }
+
+        return new TypedModule(functionPrototypes, structTypes);
+    }
+
+    public TypedModule(List<FuncPrototypeNode> functionPrototypes, List<NubStructType> structTypes)
+    {
+        FunctionPrototypes = functionPrototypes;
+        StructTypes = structTypes;
+    }
+
+    public List<FuncPrototypeNode> FunctionPrototypes { get; set; }
+    public List<NubStructType> StructTypes { get; set; }
+}

compiler/NubLang/Utils.cs

@@ -0,0 +1,31 @@
+namespace NubLang;
+
+public static class Utils
+{
+    public static int LevenshteinDistance(string a, string b)
+    {
+        if (a == b) return 0;
+        if (a.Length == 0) return b.Length;
+        if (b.Length == 0) return a.Length;
+
+        var costs = new int[b.Length + 1];
+        for (int j = 0; j <= b.Length; j++) costs[j] = j;
+
+        for (int i = 1; i <= a.Length; i++)
+        {
+            costs[0] = i;
+            int prevCost = i - 1;
+            for (int j = 1; j <= b.Length; j++)
+            {
+                int currentCost = costs[j];
+                costs[j] = Math.Min(
+                    Math.Min(costs[j - 1] + 1, costs[j] + 1),
+                    prevCost + (a[i - 1] == b[j - 1] ? 0 : 1)
+                );
+                prevCost = currentCost;
+            }
+        }
+
+        return costs[b.Length];
+    }
+}

examples/hello-world/main.nub

@@ -1,4 +1,4 @@
-module "main"
+module main
 
 extern "puts" func puts(text: ^i8)
 

examples/playgroud/build.sh

@@ -0,0 +1,6 @@
+#!/bin/bash
+
+set -euo pipefail
+
+obj=$(nubc main.nub)
+clang $obj ../../runtime/.build/runtime.o -o .build/out

examples/playgroud/main.nub

@@ -0,0 +1,45 @@
+module main
+
+extern "puts" func puts(text: ^i8)
+
+struct Name
+{
+    first: ^i8
+    last: ^i8
+}
+
+struct Human
+{
+    age: u64
+    name: &Name
+}
+
+extern "main" func main(argc: i64, argv: [?]^i8): i64
+{
+    let x: &Human = {
+        age = 23
+        name = {
+            first = "oliver"
+            last = "stene"
+        }
+    }
+
+    let z: Human = {
+        age = 23
+        name = {
+            first = "oliver"
+            last = "stene"
+        }
+    }
+
+    test(x)
+
+    let y = x
+
+    return 0
+}
+
+func test(x: &Human): &Human
+{
+    return x
+}

examples/raylib/generated/raylib.nub

@@ -1,4 +1,4 @@
-module "raylib"
+module raylib
 
 export struct Vector2
 {

examples/raylib/main.nub

@@ -1,11 +1,9 @@
-import "raylib"
+import raylib
 
-module "main"
+module main
 
 extern "main" func main(argc: i64, argv: [?]^i8): i64
 {
-    let uwu: []i32 = [1, 2]
-
     raylib::SetConfigFlags(raylib::ConfigFlags.FLAG_VSYNC_HINT | raylib::ConfigFlags.FLAG_WINDOW_RESIZABLE)
 
     raylib::InitWindow(1600, 900, "Hi from nub-lang")

runtime/.gitignore

@@ -0,0 +1 @@
+.build

runtime/build.sh

@@ -0,0 +1,6 @@
+#!/bin/bash
+
+set -euo pipefail
+
+mkdir -p .build
+clang -c runtime.c -o .build/runtime.o

runtime/ref.c

@@ -0,0 +1,42 @@
+#include "ref.h"
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+void *rc_alloc(size_t size, void (*destructor)(void *self))
+{
+    printf("rc_alloc %zu bytes\n", size);
+    ref_header *header = malloc(sizeof(ref_header) + size);
+    if (!header)
+    {
+        exit(69);
+    }
+
+    header->ref_count = 1;
+    header->destructor = destructor;
+
+    return (void *)(header + 1);
+}
+
+void rc_retain(void *obj)
+{
+    printf("rc_retain\n");
+    ref_header *header = ((ref_header *)obj) - 1;
+    header->ref_count++;
+}
+
+void rc_release(void *obj)
+{
+    ref_header *header = ((ref_header *)obj) - 1;
+    printf("rc_release\n");
+    if (--header->ref_count == 0)
+    {
+        if (header->destructor)
+        {
+            header->destructor(obj);
+        }
+
+        free(header);
+        printf("rc_free\n");
+    }
+}

runtime/ref.h

@@ -0,0 +1,13 @@
+#pragma once
+
+#include <stddef.h>
+
+typedef struct
+{
+    int ref_count;
+    void (*destructor)(void *self);
+} ref_header;
+
+void *rc_alloc(size_t size, void (*destructor)(void *self));
+void rc_retain(void *obj);
+void rc_release(void *obj);

runtime/runtime.c

@@ -0,0 +1 @@
+#include "ref.c"