Add support for global functions

example/program.nub

@@ -1,6 +1,6 @@
 import "core";
 
-func main() {
+global func main() {
     let x = "test";
     puts(x);
 }

lang/Nub.Lang/Backend/Generator.cs

@@ -50,7 +50,11 @@ public class Generator
     {
         _variables.Clear();
         var parameters = node.Parameters.Select(p => $"{QbeTypeName(p.Type)} %{p.Name}");
-        _builder.Append("export function ");
+        if (node.Global)
+        {
+            _builder.Append("export ");
+        }
+        _builder.Append("function ");
         if (node.ReturnType.HasValue)
         {
             _builder.Append($"{QbeTypeName(node.ReturnType.Value)} ");
@@ -113,10 +117,12 @@ public class Generator
 
     private void GenerateBreak()
     {
+        throw new NotImplementedException();
     }
 
     private void GenerateContinue()
     {
+        throw new NotImplementedException();
     }
 
     private void GenerateStatementFuncCall(FuncCallStatementNode funcCall)
@@ -134,6 +140,7 @@ public class Generator
 
     private void GenerateIf(IfNode ifStatement)
     {
+        throw new NotImplementedException();
     }
 
     private void GenerateReturn(ReturnNode @return)
@@ -161,6 +168,7 @@ public class Generator
 
     private void GenerateWhile(WhileNode whileStatement)
     {
+        throw new NotImplementedException();
     }
 
     private string GenerateExpression(ExpressionNode expression)

lang/Nub.Lang/Frontend/Lexing/Lexer.cs

@@ -5,6 +5,7 @@ public class Lexer
     private static readonly Dictionary<string, Symbol> Keywords = new()
     { 
         ["func"] = Symbol.Func,
+        ["global"] = Symbol.Global,
         ["extern"] = Symbol.Extern,
         ["import"] = Symbol.Import,
         ["let"] = Symbol.Let,

lang/Nub.Lang/Frontend/Lexing/SymbolToken.cs

@@ -10,6 +10,7 @@ public enum Symbol
     Whitespace,
     Import,
     Extern,
+    Global,
     Func,
     Return,
     Let,

lang/Nub.Lang/Frontend/Parsing/LocalFuncDefinitionNode.cs

@@ -1,11 +1,12 @@
 namespace Nub.Lang.Frontend.Parsing;
 
-public class LocalFuncDefinitionNode(string name, List<FuncParameter> parameters, BlockNode body, Optional<NubType> returnType) : DefinitionNode
+public class LocalFuncDefinitionNode(string name, List<FuncParameter> parameters, BlockNode body, Optional<NubType> returnType, bool global) : DefinitionNode
 {
     public string Name { get; } = name;
     public List<FuncParameter> Parameters { get; } = parameters;
     public BlockNode Body { get; } = body;
     public Optional<NubType> ReturnType { get; } = returnType;
+    public bool Global { get; } = global;
 
     public override string ToString() => $"{Name}({string.Join(", ", Parameters.Select(p => p.ToString()))}){(ReturnType.HasValue ? ": " + ReturnType.Value : "")}";
 }

lang/Nub.Lang/Frontend/Parsing/Parser.cs

@@ -44,6 +44,7 @@ public class Parser
         return keyword.Symbol switch
         {
             Symbol.Func => ParseFuncDefinition(),
+            Symbol.Global => ParseGlobalFuncDefinition(),
             Symbol.Extern => ParseExternFuncDefinition(),
             Symbol.Struct => ParseStruct(),
             _ => throw new Exception("Unexpected symbol: " + keyword.Symbol)
@@ -72,7 +73,33 @@ public class Parser
 
         var body = ParseBlock();
 
-        return new LocalFuncDefinitionNode(name.Value, parameters, body, returnType);
+        return new LocalFuncDefinitionNode(name.Value, parameters, body, returnType, false);
+    }
+    
+    private LocalFuncDefinitionNode ParseGlobalFuncDefinition()
+    {
+        ExpectSymbol(Symbol.Func);
+        var name = ExpectIdentifier();
+        List<FuncParameter> parameters = [];
+        ExpectSymbol(Symbol.OpenParen);
+        if (!TryExpectSymbol(Symbol.CloseParen))
+        {
+            while (!TryExpectSymbol(Symbol.CloseParen))
+            {
+                parameters.Add(ParseFuncParameter());
+                TryExpectSymbol(Symbol.Comma);
+            }
+        }
+
+        var returnType = Optional<NubType>.Empty();
+        if (TryExpectSymbol(Symbol.Colon))
+        {
+            returnType = ParseTypeInstance();
+        }
+
+        var body = ParseBlock();
+
+        return new LocalFuncDefinitionNode(name.Value, parameters, body, returnType, true);
     }
 
     private ExternFuncDefinitionNode ParseExternFuncDefinition()

std/baseline/runtime.asm

@@ -1,8 +1,9 @@
 global _start
-extern main
+extern main, gc_init
 
 section .text
 _start:
+    call gc_init
     call main
     mov rax, 60
     mov rdi, 0