Module system

compiler/NubLang.CLI/Program.cs

@@ -60,7 +60,7 @@ foreach (var file in options.Files)
     syntaxTrees.Add(syntaxTree);
 }
 
-var moduleSignatures = ModuleSignature.CollectFromSyntaxTrees(syntaxTrees);
+var moduleSignatures = Module.CollectFromSyntaxTrees(syntaxTrees);
 
 var definitions = new List<DefinitionNode>();
 

compiler/NubLang/Code/SourceLocation.cs

@@ -1,6 +1,6 @@
 namespace NubLang.Code;
 
-public readonly struct SourceLocation : IEquatable<SourceLocation>
+public readonly struct SourceLocation : IEquatable<SourceLocation>, IComparable<SourceLocation>
 {
     public static SourceLocation Zero => new(0, 0);
 
@@ -39,4 +39,10 @@ public readonly struct SourceLocation : IEquatable<SourceLocation>
     public static bool operator >(SourceLocation left, SourceLocation right) => left.Line > right.Line || (left.Line == right.Line && left.Column > right.Column);
     public static bool operator <=(SourceLocation left, SourceLocation right) => left.Line <= right.Line || (left.Line == right.Line && left.Column <= right.Column);
     public static bool operator >=(SourceLocation left, SourceLocation right) => left.Line >= right.Line || (left.Line == right.Line && left.Column >= right.Column);
+
+    public int CompareTo(SourceLocation other)
+    {
+        var lineComparison = Line.CompareTo(other.Line);
+        return lineComparison != 0 ? lineComparison : Column.CompareTo(other.Column);
+    }
 }

compiler/NubLang/Code/SourceSpan.cs

@@ -1,6 +1,6 @@
 namespace NubLang.Code;
 
-public readonly struct SourceSpan : IEquatable<SourceSpan>
+public readonly struct SourceSpan : IEquatable<SourceSpan>, IComparable<SourceSpan>
 {
     public static SourceSpan Zero => new(SourceLocation.Zero, SourceLocation.Zero);
 
@@ -54,4 +54,15 @@ public readonly struct SourceSpan : IEquatable<SourceSpan>
 
     public static bool operator ==(SourceSpan left, SourceSpan right) => Equals(left, right);
     public static bool operator !=(SourceSpan left, SourceSpan right) => !Equals(left, right);
+    
+    public static bool operator <(SourceSpan left, SourceSpan right) => left.CompareTo(right) < 0;
+    public static bool operator <=(SourceSpan left, SourceSpan right) => left.CompareTo(right) <= 0;
+    public static bool operator >(SourceSpan left, SourceSpan right) => left.CompareTo(right) > 0;
+    public static bool operator >=(SourceSpan left, SourceSpan right) => left.CompareTo(right) >= 0;
+
+    public int CompareTo(SourceSpan other)
+    {
+        var startComparison = Start.CompareTo(other.Start);
+        return startComparison != 0 ? startComparison : End.CompareTo(other.End);
+    }
 }

compiler/NubLang/Diagnostics/Diagnostic.cs

@@ -27,7 +27,7 @@ public class Diagnostic
                 var first = node.Tokens.FirstOrDefault();
                 if (first?.FileSpan != null)
                 {
-                    var span = SourceSpan.Merge(node.Tokens.Select(x => x.FileSpan?.Span ?? SourceSpan.Zero));
+                    var span = SourceSpan.Merge(node.Tokens.Select(x => x.FileSpan.Span));
                     At(new SourceFileSpan(first.FileSpan.SourceFile, span));
                 }
             }

compiler/NubLang/Generation/QBE/QBEGenerator.cs

@@ -11,7 +11,7 @@ public class QBEGenerator
 {
     private readonly QBEWriter _writer;
     private readonly IReadOnlyList<DefinitionNode> _definitions;
-    private readonly IReadOnlyDictionary<string, ModuleSignature> _moduleSignatures;
+    private readonly IReadOnlyDictionary<string, Module> _moduleSignatures;
 
     private readonly List<CStringLiteral> _cStringLiterals = [];
     private readonly List<StringLiteral> _stringLiterals = [];
@@ -23,7 +23,7 @@ public class QBEGenerator
     private int _stringLiteralIndex;
     private bool _codeIsReachable = true;
 
-    public QBEGenerator(IReadOnlyList<DefinitionNode> definitions, IReadOnlyDictionary<string, ModuleSignature> moduleSignatures)
+    public QBEGenerator(IReadOnlyList<DefinitionNode> definitions, IReadOnlyDictionary<string, Module> moduleSignatures)
     {
         _definitions = definitions;
         _moduleSignatures = moduleSignatures;
@@ -46,7 +46,7 @@ public class QBEGenerator
         {
             foreach (var structType in signature.ExportedStructTypes)
             {
-                EmitStructType(module, structType);
+                EmitStructType(module, structType.StructType);
                 _writer.NewLine();
             }
         }
@@ -410,8 +410,6 @@ public class QBEGenerator
 
     private void EmitStructDefinition(StructNode structDef)
     {
-        var type = TypeResolver.ResolveStructType(structDef.Module, structDef.Name, _moduleSignatures);
-
         // _writer.WriteLine($"export function {StructCtorName(_module.Name, structDef.Name)}() {{");
         // _writer.WriteLine("@start");
         // _writer.Indented($"%struct =l alloc8 {SizeOf(type)}");
@@ -660,7 +658,6 @@ public class QBEGenerator
 
     private string EmitFuncIdentifier(FuncIdentifierNode funcIdent)
     {
-        // todo(nub31): Support for extern funcs
         return FuncName(funcIdent.Module, funcIdent.Name);
     }
 
@@ -755,9 +752,7 @@ public class QBEGenerator
     private string EmitAddressOfStructFieldAccess(StructFieldAccessNode structFieldAccess)
     {
         var target = EmitExpression(structFieldAccess.Target);
-
+        var offset = OffsetOf(structFieldAccess.StructType, structFieldAccess.Field);
-        var structType = TypeResolver.ResolveStructType(structFieldAccess.StructType.Module, structFieldAccess.StructType.Name, _moduleSignatures);
-        var offset = OffsetOf(structType, structFieldAccess.Field);
 
         var address = TmpName();
         _writer.Indented($"{address} =l add {target}, {offset}");
@@ -1398,8 +1393,8 @@ public class QBEGenerator
 
     private string FuncName(string module, string name)
     {
-        var type = TypeResolver.ResolveFunctionType(module, name, _moduleSignatures);
+        var function = _moduleSignatures[module].AllFunctions.First(x => x.Name == name);
-        var symbol = type.ExternSymbol ?? $"{module}.{name}";
+        var symbol = function.ExternSymbol ?? $"{module}.{name}";
         return "$" + symbol;
     }
 

compiler/NubLang/Parsing/Parser.cs

@@ -474,7 +474,7 @@ public sealed class Parser
         var expr = token switch
         {
             LiteralToken literal => new LiteralSyntax(GetTokens(startIndex), literal.Value, literal.Kind),
-            IdentifierToken identifier => new LocalIdentifierSyntax(GetTokens(startIndex), identifier.Value),
+            IdentifierToken identifier => ParseIdentifier(startIndex, identifier),
             SymbolToken symbolToken => symbolToken.Symbol switch
             {
                 Symbol.OpenParen => ParseParenthesizedExpression(),
@@ -499,6 +499,17 @@ public sealed class Parser
         return ParsePostfixOperators(expr);
     }
 
+    private ExpressionSyntax ParseIdentifier(int startIndex, IdentifierToken identifier)
+    {
+        if (TryExpectSymbol(Symbol.DoubleColon))
+        {
+            var name = ExpectIdentifier();
+            return new ModuleIdentifierSyntax(GetTokens(startIndex), identifier.Value, name.Value);
+        }
+
+        return new LocalIdentifierSyntax(GetTokens(startIndex), identifier.Value);
+    }
+
     private ExpressionSyntax ParseParenthesizedExpression()
     {
         var expression = ParseExpression();
@@ -690,14 +701,27 @@ public sealed class Parser
                 return new FloatTypeSyntax(GetTokens(startIndex), size);
             }
 
-            return name.Value switch
+            switch (name.Value)
             {
-                "void" => new VoidTypeSyntax(GetTokens(startIndex)),
+                case "void":
-                "string" => new StringTypeSyntax(GetTokens(startIndex)),
+                    return new VoidTypeSyntax(GetTokens(startIndex));
-                "cstring" => new CStringTypeSyntax(GetTokens(startIndex)),
+                case "string":
-                "bool" => new BoolTypeSyntax(GetTokens(startIndex)),
+                    return new StringTypeSyntax(GetTokens(startIndex));
-                _ => new CustomTypeSyntax(GetTokens(startIndex), _moduleName, name.Value)
+                case "cstring":
-            };
+                    return new CStringTypeSyntax(GetTokens(startIndex));
+                case "bool":
+                    return new BoolTypeSyntax(GetTokens(startIndex));
+                default:
+                {
+                    if (TryExpectSymbol(Symbol.DoubleColon))
+                    {
+                        var customTypeName = ExpectIdentifier().Value;
+                        return new CustomTypeSyntax(GetTokens(startIndex), name.Value, customTypeName);
+                    }
+
+                    return new CustomTypeSyntax(GetTokens(startIndex), _moduleName, name.Value);
+                }
+            }
         }
 
         if (TryExpectSymbol(Symbol.Caret))

compiler/NubLang/Tokenization/Token.cs

@@ -41,6 +41,7 @@ public enum Symbol
     Break,
     Continue,
     Colon,
+    DoubleColon,
     OpenParen,
     CloseParen,
     OpenBrace,

compiler/NubLang/Tokenization/Tokenizer.cs

@@ -35,6 +35,7 @@ public sealed class Tokenizer
         [['>', '>']] = Symbol.RightShift,
         [['&', '&']] = Symbol.And,
         [['|', '|']] = Symbol.Or,
+        [[':', ':']] = Symbol.DoubleColon,
         [[':']] = Symbol.Colon,
         [['(']] = Symbol.OpenParen,
         [[')']] = Symbol.CloseParen,

compiler/NubLang/TypeChecking/Module.cs

@@ -3,11 +3,11 @@ using NubLang.TypeChecking.Node;
 
 namespace NubLang.TypeChecking;
 
-public class ModuleSignature
+public class Module
 {
-    public static IReadOnlyDictionary<string, ModuleSignature> CollectFromSyntaxTrees(IReadOnlyList<SyntaxTree> syntaxTrees)
+    public static IReadOnlyDictionary<string, Module> CollectFromSyntaxTrees(IReadOnlyList<SyntaxTree> syntaxTrees)
     {
-        var modules = new Dictionary<string, ModuleSignature>();
+        var modules = new Dictionary<string, Module>();
 
         foreach (var syntaxTree in syntaxTrees)
         {
@@ -15,7 +15,7 @@ public class ModuleSignature
 
             if (!modules.TryGetValue(moduleName, out var module))
             {
-                module = new ModuleSignature();
+                module = new Module();
                 modules[moduleName] = module;
             }
 
@@ -25,11 +25,11 @@ public class ModuleSignature
                 {
                     case FuncSyntax funcDef:
                     {
-                        var parameters = funcDef.Signature.Parameters.Select(p => TypeResolver.ResolveType(p.Type, modules)).ToList();
+                        var parameters = funcDef.Signature.Parameters.Select(p => ResolveType(p.Type)).ToList();
-                        var returnType = TypeResolver.ResolveType(funcDef.Signature.ReturnType, modules);
+                        var returnType = ResolveType(funcDef.Signature.ReturnType);
 
-                        var type = new FuncTypeNode(parameters, returnType, funcDef.ExternSymbol);
+                        var type = new FuncTypeNode(parameters, returnType);
-                        module._functions.Add(funcDef.Name, new ModuleMember<FuncTypeNode>(type, def.Exported));
+                        module._functions.Add(new ModuleFuncType(def.Exported, funcDef.Name, funcDef.ExternSymbol, type));
                         break;
                     }
                     case InterfaceSyntax interfaceDef:
@@ -38,13 +38,13 @@ public class ModuleSignature
                         for (var i = 0; i < interfaceDef.Functions.Count; i++)
                         {
                             var function = interfaceDef.Functions[i];
-                            var parameters = function.Signature.Parameters.Select(p => TypeResolver.ResolveType(p.Type, modules)).ToList();
+                            var parameters = function.Signature.Parameters.Select(p => ResolveType(p.Type)).ToList();
-                            var returnType = TypeResolver.ResolveType(function.Signature.ReturnType, modules);
+                            var returnType = ResolveType(function.Signature.ReturnType);
                             functions.Add(new InterfaceTypeFunc(function.Name, new FuncTypeNode(parameters, returnType), i));
                         }
 
                         var type = new InterfaceTypeNode(moduleName, interfaceDef.Name, functions);
-                        module._interfaces.Add(new ModuleMember<InterfaceTypeNode>(type, def.Exported));
+                        module._interfaces.Add(new ModuleInterfaceType(def.Exported, type));
                         break;
                     }
                     case StructSyntax structDef:
@@ -52,14 +52,14 @@ public class ModuleSignature
                         var fields = new List<StructTypeField>();
                         foreach (var field in structDef.Fields)
                         {
-                            fields.Add(new StructTypeField(field.Name, TypeResolver.ResolveType(field.Type, modules), field.Index, field.Value.HasValue));
+                            fields.Add(new StructTypeField(field.Name, ResolveType(field.Type), field.Index, field.Value.HasValue));
                         }
 
                         var functions = new List<StructTypeFunc>();
                         foreach (var function in structDef.Functions)
                         {
-                            var parameters = function.Signature.Parameters.Select(p => TypeResolver.ResolveType(p.Type, modules)).ToList();
+                            var parameters = function.Signature.Parameters.Select(p => ResolveType(p.Type)).ToList();
-                            var returnType = TypeResolver.ResolveType(function.Signature.ReturnType, modules);
+                            var returnType = ResolveType(function.Signature.ReturnType);
                             functions.Add(new StructTypeFunc(function.Name, new FuncTypeNode(parameters, returnType)));
                         }
 
@@ -71,7 +71,7 @@ public class ModuleSignature
                                 throw new Exception("Interface implementation is not a custom type");
                             }
 
-                            var resolvedType = TypeResolver.ResolveCustomType(customType.Module, customType.Name, modules);
+                            var resolvedType = ResolveType(customType);
                             if (resolvedType is not InterfaceTypeNode interfaceType)
                             {
                                 throw new Exception("Interface implementation is not a interface");
@@ -81,7 +81,7 @@ public class ModuleSignature
                         }
 
                         var type = new StructTypeNode(moduleName, structDef.Name, fields, functions, interfaceImplementations);
-                        module._structs.Add(new ModuleMember<StructTypeNode>(type, def.Exported));
+                        module._structs.Add(new ModuleStructType(def.Exported, type));
                         break;
                     }
                     default:
@@ -93,29 +93,97 @@ public class ModuleSignature
         }
 
         return modules;
-    }
 
-    private class ModuleMember<T>
+        TypeNode ResolveType(TypeSyntax type)
         {
-        public ModuleMember(T value, bool exported)
+            return type switch
             {
-            Value = value;
+                BoolTypeSyntax => new BoolTypeNode(),
-            Exported = exported;
+                CStringTypeSyntax => new CStringTypeNode(),
+                IntTypeSyntax i => new IntTypeNode(i.Signed, i.Width),
+                CustomTypeSyntax c => ResolveCustomType(c.Module, c.Name),
+                FloatTypeSyntax f => new FloatTypeNode(f.Width),
+                FuncTypeSyntax func => new FuncTypeNode(func.Parameters.Select(ResolveType).ToList(), ResolveType(func.ReturnType)),
+                ArrayTypeSyntax arr => new ArrayTypeNode(ResolveType(arr.BaseType)),
+                PointerTypeSyntax ptr => new PointerTypeNode(ResolveType(ptr.BaseType)),
+                StringTypeSyntax => new StringTypeNode(),
+                VoidTypeSyntax => new VoidTypeNode(),
+                _ => throw new NotSupportedException($"Unknown type syntax: {type}")
+            };
         }
 
-        public T Value { get; set; }
+        TypeNode ResolveCustomType(string moduleName, string typeName)
-        public bool Exported { get; set; }
+        {
+            if (!modules.TryGetValue(moduleName, out var module))
+            {
+                throw new Exception("Module not found: " + moduleName);
             }
 
-    private readonly List<ModuleMember<StructTypeNode>> _structs = [];
+            var structType = module.AllStructTypes.FirstOrDefault(x => x.StructType.Name == typeName);
-    private readonly List<ModuleMember<InterfaceTypeNode>> _interfaces = [];
+            if (structType != null)
-    private readonly Dictionary<string, ModuleMember<FuncTypeNode>> _functions = [];
+            {
+                return structType.StructType;
+            }
 
-    public IReadOnlyList<StructTypeNode> ExportedStructTypes => _structs.Where(x => x.Exported).Select(x => x.Value).ToList();
+            var interfaceType = module.AllInterfaceTypes.FirstOrDefault(x => x.InterfaceType.Name == typeName);
-    public IReadOnlyList<InterfaceTypeNode> ExportedInterfaceTypes => _interfaces.Where(x => x.Exported).Select(x => x.Value).ToList();
+            if (interfaceType != null)
-    public IReadOnlyDictionary<string, FuncTypeNode> ExportedFunctions => _functions.Where(x => x.Value.Exported).ToDictionary(x => x.Key, x => x.Value.Value);
+            {
+                return interfaceType.InterfaceType;
+            }
 
-    public IReadOnlyList<StructTypeNode> AllStructTypes => _structs.Select(x => x.Value).ToList();
+            throw new Exception($"Type {typeName} not found in module {moduleName}");
-    public IReadOnlyList<InterfaceTypeNode> AllInterfaceTypes => _interfaces.Select(x => x.Value).ToList();
+        }
-    public IReadOnlyDictionary<string, FuncTypeNode> AllFunctions => _functions.ToDictionary(x => x.Key, x => x.Value.Value);
+    }
+
+    private readonly List<ModuleStructType> _structs = [];
+    private readonly List<ModuleInterfaceType> _interfaces = [];
+    private readonly List<ModuleFuncType> _functions = [];
+
+    public IReadOnlyList<ModuleStructType> ExportedStructTypes => _structs.Where(x => x.Exported).ToList();
+    public IReadOnlyList<ModuleInterfaceType> ExportedInterfaceTypes => _interfaces.Where(x => x.Exported).ToList();
+    public IReadOnlyList<ModuleFuncType> ExportedFunctions => _functions.Where(x => x.Exported).ToList();
+
+    public IReadOnlyList<ModuleStructType> AllStructTypes => _structs;
+    public IReadOnlyList<ModuleInterfaceType> AllInterfaceTypes => _interfaces;
+    public IReadOnlyList<ModuleFuncType> AllFunctions => _functions;
+}
+
+public class ModuleStructType
+{
+    public ModuleStructType(bool exported, StructTypeNode structType)
+    {
+        Exported = exported;
+        StructType = structType;
+    }
+
+    public bool Exported { get; }
+    public StructTypeNode StructType { get; }
+}
+
+public class ModuleInterfaceType
+{
+    public ModuleInterfaceType(bool exported, InterfaceTypeNode interfaceType)
+    {
+        Exported = exported;
+        InterfaceType = interfaceType;
+    }
+
+    public bool Exported { get; }
+    public InterfaceTypeNode InterfaceType { get; }
+}
+
+public class ModuleFuncType
+{
+    public ModuleFuncType(bool exported, string name, string? externSymbol, FuncTypeNode funcType)
+    {
+        Exported = exported;
+        Name = name;
+        ExternSymbol = externSymbol;
+        FuncType = funcType;
+    }
+
+    public bool Exported { get; }
+    public string Name { get; }
+    public string? ExternSymbol { get; }
+    public FuncTypeNode FuncType { get; }
 }

compiler/NubLang/TypeChecking/Node/TypeNode.cs

@@ -110,9 +110,8 @@ public class BoolTypeNode : SimpleTypeNode
     public override int GetHashCode() => HashCode.Combine(typeof(BoolTypeNode));
 }
 
-public class FuncTypeNode(IReadOnlyList<TypeNode> parameters, TypeNode returnType, string? externSymbol = null) : SimpleTypeNode
+public class FuncTypeNode(IReadOnlyList<TypeNode> parameters, TypeNode returnType) : SimpleTypeNode
 {
-    public string? ExternSymbol { get; } = externSymbol;
     public IReadOnlyList<TypeNode> Parameters { get; } = parameters;
     public TypeNode ReturnType { get; } = returnType;
 

compiler/NubLang/TypeChecking/TypeChecker.cs

@@ -8,7 +8,7 @@ namespace NubLang.TypeChecking;
 public sealed class TypeChecker
 {
     private readonly SyntaxTree _syntaxTree;
-    private readonly IReadOnlyDictionary<string, ModuleSignature> _moduleSignatures;
+    private readonly IReadOnlyDictionary<string, Module> _importedModules;
 
     private readonly Stack<Scope> _scopes = [];
     private readonly Stack<TypeNode> _funcReturnTypes = [];
@@ -16,10 +16,10 @@ public sealed class TypeChecker
 
     private Scope Scope => _scopes.Peek();
 
-    public TypeChecker(SyntaxTree syntaxTree, IReadOnlyDictionary<string, ModuleSignature> moduleSignatures)
+    public TypeChecker(SyntaxTree syntaxTree, IReadOnlyDictionary<string, Module> moduleSignatures)
     {
         _syntaxTree = syntaxTree;
-        _moduleSignatures = moduleSignatures.Where(x => syntaxTree.Metadata.Imports.Contains(x.Key) || _syntaxTree.Metadata.ModuleName == x.Key).ToDictionary();
+        _importedModules = moduleSignatures.Where(x => syntaxTree.Metadata.Imports.Contains(x.Key) || _syntaxTree.Metadata.ModuleName == x.Key).ToDictionary();
     }
 
     public IReadOnlyList<Diagnostic> GetDiagnostics() => _diagnostics;
@@ -346,18 +346,43 @@ public sealed class TypeChecker
         }
 
         // Second, look in the current module for a function matching the identifier
-        var module = _moduleSignatures[_syntaxTree.Metadata.ModuleName];
+        var module = _importedModules[_syntaxTree.Metadata.ModuleName];
-        if (module.AllFunctions.TryGetValue(expression.Name, out var function))
+        var function = module.AllFunctions.FirstOrDefault(x => x.Name == expression.Name);
+
+        if (function != null)
         {
-            return new FuncIdentifierNode(function, _syntaxTree.Metadata.ModuleName, expression.Name);
+            return new FuncIdentifierNode(function.FuncType, _syntaxTree.Metadata.ModuleName, expression.Name);
         }
 
-        throw new TypeCheckerException(Diagnostic.Error($"Identifier {expression.Name} not found").At(expression).Build());
+        throw new TypeCheckerException(Diagnostic.Error($"Symbol {expression.Name} not found").At(expression).Build());
     }
 
     private ExpressionNode CheckModuleIdentifier(ModuleIdentifierSyntax expression)
     {
-        throw new NotImplementedException();
+        if (!_importedModules.TryGetValue(expression.Module, out var module))
+        {
+            throw new TypeCheckerException(Diagnostic.Error($"Module {expression.Module} not found").WithHelp($"import \"{expression.Module}\"").At(expression).Build());
+        }
+
+        // First, look for the exported function in the specified module (or all functions if current module)
+        if (expression.Module == _syntaxTree.Metadata.ModuleName)
+        {
+            var function = module.AllFunctions.FirstOrDefault(x => x.Name == expression.Name);
+            if (function != null)
+            {
+                return new FuncIdentifierNode(function.FuncType, expression.Module, expression.Name);
+            }
+        }
+        else
+        {
+            var function = module.ExportedFunctions.FirstOrDefault(x => x.Name == expression.Name);
+            if (function != null)
+            {
+                return new FuncIdentifierNode(function.FuncType, expression.Module, expression.Name);
+            }
+        }
+
+        throw new TypeCheckerException(Diagnostic.Error($"No exported symbol {expression.Name} not found in module {expression.Module}").At(expression).Build());
     }
 
     private LiteralNode CheckLiteral(LiteralSyntax expression, TypeNode? expectedType)
@@ -406,9 +431,61 @@ public sealed class TypeChecker
         return new BlockNode(statements);
     }
 
-    private TypeNode ResolveType(TypeSyntax fieldType)
+    private TypeNode ResolveType(TypeSyntax type)
     {
-        return TypeResolver.ResolveType(fieldType, _moduleSignatures);
+        return type switch
+        {
+            BoolTypeSyntax => new BoolTypeNode(),
+            CStringTypeSyntax => new CStringTypeNode(),
+            IntTypeSyntax i => new IntTypeNode(i.Signed, i.Width),
+            CustomTypeSyntax c => ResolveCustomType(c),
+            FloatTypeSyntax f => new FloatTypeNode(f.Width),
+            FuncTypeSyntax func => new FuncTypeNode(func.Parameters.Select(ResolveType).ToList(), ResolveType(func.ReturnType)),
+            ArrayTypeSyntax arr => new ArrayTypeNode(ResolveType(arr.BaseType)),
+            PointerTypeSyntax ptr => new PointerTypeNode(ResolveType(ptr.BaseType)),
+            StringTypeSyntax => new StringTypeNode(),
+            VoidTypeSyntax => new VoidTypeNode(),
+            _ => throw new NotSupportedException($"Unknown type syntax: {type}")
+        };
+    }
+
+    private TypeNode ResolveCustomType(CustomTypeSyntax customType)
+    {
+        if (!_importedModules.TryGetValue(customType.Module, out var module))
+        {
+            throw new Exception("Module not found: " + customType.Module);
+        }
+
+        if (customType.Module == _syntaxTree.Metadata.ModuleName)
+        {
+            var structType = module.AllStructTypes.FirstOrDefault(x => x.StructType.Name == customType.Name);
+            if (structType != null)
+            {
+                return structType.StructType;
+            }
+
+            var interfaceType = module.AllInterfaceTypes.FirstOrDefault(x => x.InterfaceType.Name == customType.Name);
+            if (interfaceType != null)
+            {
+                return interfaceType.InterfaceType;
+            }
+        }
+        else
+        {
+            var structType = module.ExportedStructTypes.FirstOrDefault(x => x.StructType.Name == customType.Name);
+            if (structType != null)
+            {
+                return structType.StructType;
+            }
+
+            var interfaceType = module.ExportedInterfaceTypes.FirstOrDefault(x => x.InterfaceType.Name == customType.Name);
+            if (interfaceType != null)
+            {
+                return interfaceType.InterfaceType;
+            }
+        }
+
+        throw new TypeCheckerException(Diagnostic.Error($"Type {customType.Name} not found in module {customType.Module}").At(customType).Build());
     }
 }
 

compiler/NubLang/TypeResolver.cs

@@ -1,95 +0,0 @@
-using NubLang.Parsing.Syntax;
-using NubLang.TypeChecking;
-using NubLang.TypeChecking.Node;
-
-namespace NubLang;
-
-public static class TypeResolver
-{
-    public static TypeNode ResolveType(TypeSyntax type, IReadOnlyDictionary<string, ModuleSignature> modules)
-    {
-        return type switch
-        {
-            BoolTypeSyntax => new BoolTypeNode(),
-            CStringTypeSyntax => new CStringTypeNode(),
-            IntTypeSyntax i => new IntTypeNode(i.Signed, i.Width),
-            CustomTypeSyntax c => ResolveCustomType(c.Module, c.Name, modules),
-            FloatTypeSyntax f => new FloatTypeNode(f.Width),
-            FuncTypeSyntax func => new FuncTypeNode(func.Parameters.Select(x => ResolveType(x, modules)).ToList(), ResolveType(func.ReturnType, modules)),
-            ArrayTypeSyntax arr => new ArrayTypeNode(ResolveType(arr.BaseType, modules)),
-            PointerTypeSyntax ptr => new PointerTypeNode(ResolveType(ptr.BaseType, modules)),
-            StringTypeSyntax => new StringTypeNode(),
-            VoidTypeSyntax => new VoidTypeNode(),
-            _ => throw new NotSupportedException($"Unknown type syntax: {type}")
-        };
-    }
-
-    public static TypeNode ResolveCustomType(string moduleName, string typeName, IReadOnlyDictionary<string, ModuleSignature> modules)
-    {
-        if (!modules.TryGetValue(moduleName, out var module))
-        {
-            throw new Exception("Module not found: " + moduleName);
-        }
-
-        var structType = module.AllStructTypes.FirstOrDefault(x => x.Name == typeName);
-        if (structType != null)
-        {
-            return structType;
-        }
-
-        var interfaceType = module.AllInterfaceTypes.FirstOrDefault(x => x.Name == typeName);
-        if (interfaceType != null)
-        {
-            return interfaceType;
-        }
-
-        throw new Exception($"Type {typeName} not found in module {moduleName}");
-    }
-
-    public static StructTypeNode ResolveStructType(string moduleName, string structName, IReadOnlyDictionary<string, ModuleSignature> modules)
-    {
-        if (!modules.TryGetValue(moduleName, out var module))
-        {
-            throw new Exception("Module not found: " + moduleName);
-        }
-
-        var structType = module.AllStructTypes.FirstOrDefault(x => x.Name == structName);
-        if (structType != null)
-        {
-            return structType;
-        }
-
-        throw new Exception($"Struct type {structName} not found in module {moduleName}");
-    }
-
-    public static InterfaceTypeNode ResolveInterfaceType(string moduleName, string interfaceName, IReadOnlyDictionary<string, ModuleSignature> modules)
-    {
-        if (!modules.TryGetValue(moduleName, out var module))
-        {
-            throw new Exception("Module not found: " + moduleName);
-        }
-
-        var structType = module.AllInterfaceTypes.FirstOrDefault(x => x.Name == interfaceName);
-        if (structType != null)
-        {
-            return structType;
-        }
-
-        throw new Exception($"Interface type {interfaceName} not found in module {moduleName}");
-    }
-
-    public static FuncTypeNode ResolveFunctionType(string moduleName, string funcName, IReadOnlyDictionary<string, ModuleSignature> modules)
-    {
-        if (!modules.TryGetValue(moduleName, out var module))
-        {
-            throw new Exception("Module not found: " + moduleName);
-        }
-
-        if (module.AllFunctions.TryGetValue(funcName, out var funcType))
-        {
-            return funcType;
-        }
-
-        throw new Exception($"Function type {funcName} not found in module {moduleName}");
-    }
-}

example/main.nub

@@ -1,9 +1,20 @@
 module "main"
+import "test"
 
-extern "puts" func puts(text: cstring)
+export extern "puts" func puts(text: cstring)
+
+struct Human
+{
+    name: cstring
+    age: u64
+}
 
 func main(args: []cstring): i64
 {
-    puts("test")
+    let me: main::Human = {
+        name = "Oliver"
+        age = 21
+    }
+
     return 0
 }

example/makefile

@@ -4,7 +4,7 @@ out: .build/out.o
 	gcc -nostartfiles -o out x86_64.s .build/out.o
 
 .build/out.o: $(NUBC) main.nub
-	$(NUBC) main.nub module.nub
+	$(NUBC) main.nub
 
 .PHONY: $(NUBC)
 $(NUBC):