diff --git a/ccodegen.cpp b/ccodegen.cpp
index 95886e2..4b7e47c 100644
--- a/ccodegen.cpp
+++ b/ccodegen.cpp
@@ -680,10 +680,13 @@ parse_all_modules(){
 function Ast_Module *
 add_module(Intern_String filename){
   For(pctx->modules){
-    if(it->name == filename)
+    if(it->name == filename){
+      log_info("Returning registered module: %Q\n", filename);
       return it;
+    }
   }
 
+  log_info("Adding module: %Q\n", filename);
   Ast_Module *result = ast_module(filename);
   register_ast_file(result->name, result, true);
   pctx->modules.add(result);
@@ -722,7 +725,7 @@ begin_compilation(){
 global F64 generating_time_begin;
 global F64 generating_time_end;
 function String
-end_compilation(){
+get_compilation_result(){
   generating_time_begin = os_time();
 
 #if 1
@@ -806,7 +809,11 @@ typedef struct String{
   }
 
   String string_result = string_flatten(pctx->perm, &pctx->gen);
-  exp_destroy(pctx->heap);
   generating_time_end = os_time();
   return string_result;
 }
+
+function void
+compiler_cleanup(){
+  exp_destroy(pctx->heap);
+}
diff --git a/main.cpp b/main.cpp
index ec47dc4..7bbe029 100644
--- a/main.cpp
+++ b/main.cpp
@@ -41,12 +41,15 @@ want to export all the symbols, we can namespace them optionally.
 -------------------------------------------------------------------------------
 
 @todo
+[ ] - Better error messages when type difference
+[ ] - Casting pointers to and from void should be implicit
+[ ] - Kilobyte, Megabyte, Gigabyte
+[ ] - Mixing loads and imports leads to code duplication, is that what we want???
 [ ] - Fix field access, cant cast, cant index
 [ ] - Add parent_scope to Ast_Type
 [ ] - Switch
 [ ] - Some way to take slice of data
 [ ] - Optional function renaming in codegen
-[ ] - Multiple return values
 [ ] - Using in structs to embed members, then casting offsets to that embedded member
 
 [ ] - Comma notation when declaring variables thing1, thing2: S32
@@ -71,6 +74,7 @@ want to export all the symbols, we can namespace them optionally.
 [ ] - Conditional compilation #if
 
 @donzo
+[x] - Multiple return values
 [x] - Add c string
 [-] - Should compound resolution use an algorithm to reorder compounds to initialize all fields in order
 [x] - slices should be properly displayed in debugger
@@ -157,36 +161,19 @@ int main(int argument_count, char **arguments){
   test_intern_table();
 
 
-#if 0
-  if(argument_count > 1){
-    Scratch scratch;
-    String name = string_fmt(scratch, "%s.kl", arguments[1]);
-    String c_filename = string_fmt(scratch, "%s.c", arguments[1]);
-
-    String run_program = string_fmt(scratch, "%s.exe", arguments[1]);
-
-    Array<String> files = {scratch};
-    files.add(name);
-    String result = compile_files(files);
-
-    assert(f);
-
-
-    F64 begin = os_time();
-    system((const char *)compiler_call.str);
-    printf("\nCompile time: %f", os_time() - begin);
-
-    system((const char *)run_program.str);
-  }
-#else
   emit_line_directives = true;
+  String program_name = "main.kl"_s;
+  if(argument_count > 1){
+    program_name = string_from_cstring(arguments[1]);
+  }
+
   F64 total_time = os_time();
   begin_compilation();
-  Ast_Module *module = add_module(pctx->intern("main.kl"_s));
+  Ast_Module *module = add_module(pctx->intern(program_name));
   parse_all_modules();
   assert(module);
   resolve_everything_in_module(module);
-  String result = end_compilation();
+  String result = get_compilation_result();
   assert(os_write_file("program.c"_s, result));
   {
     Scratch scratch;
@@ -200,6 +187,5 @@ int main(int argument_count, char **arguments){
   printf("\nparsing   = %f", parsing_time_end - parsing_time_begin);
   printf("\nresolving = %f", resolving_time_end - resolving_time_begin);
   printf("\ngeneratin = %f", generating_time_end - generating_time_begin);
-#endif
   __debugbreak();
 }
diff --git a/parsing.cpp b/parsing.cpp
index a221fd8..ad499f1 100644
--- a/parsing.cpp
+++ b/parsing.cpp
@@ -675,11 +675,13 @@ register_ast_file(Intern_String filename, Ast_Module *module, B32 global_implici
   Ast_File *file = 0;
   For(module->all_loaded_files){
     if(it->filename == filename){
+      log_info("%Q :: Returning registered file: %Q\n", module->name, filename);
       file = it;
       break;
     }
   }
   if(!file){
+    log_info("%Q :: Registering file: %Q\n", module->name, filename);
     AST_NEW(File, FILE, 0, 0);
     file = result;
     file->filename = filename;
diff --git a/programs/base.kl b/programs/base.kl
index 458e039..1d606b9 100644
--- a/programs/base.kl
+++ b/programs/base.kl
@@ -1,12 +1,18 @@
-Os :: #import "os.kl"
-
+Os    :: #import "os.kl"
 SizeU :: #strict U64
 
+arena_di: U64
+
 Arena :: struct
+  di: U64 // @debug_id
   memory: Os.Memory
   alignment: U64
   len: U64
 
+  ADDITIONAL_COMMIT_SIZE :: 1024*1024
+  DEFAULT_RESERVE_SIZE   :: 1024*1024*1024
+  DEFAULT_ALIGNMENT      :: 8
+
 clamp_top_sizeu :: (val: SizeU, max: SizeU): SizeU
   if val > max
     return max
@@ -22,3 +28,22 @@ get_align_offset :: (size: SizeU, align: SizeU): SizeU
 align_up :: (size: SizeU, align: SizeU): SizeU
   result := size + get_align_offset(size, align)
   return result
+
+arena_init :: (a: *Arena)
+  a.memory    = Os.reserve(a.DEFAULT_RESERVE_SIZE)
+  a.alignment = a.DEFAULT_ALIGNMENT
+  a.di        = arena_di++
+
+arena_push_size :: (a: *Arena, size: SizeU): *void
+  generous_size := size + a.alignment
+  if a.len + generous_size > a.memory.commit
+    if a.memory.reserve == 0
+      arena_init(a)
+    result := Os.commit(&a.memory, generous_size + a.ADDITIONAL_COMMIT_SIZE)
+    assert(result == true)
+  a.len = align_up(a.len, a.alignment)
+  assert(a.memory.reserve  > a.len + a.memory.commit)
+  result: *void = a.memory.data + a.len
+  a.len += size
+  return result
+
diff --git a/programs/main.kl b/programs/main.kl
index 983a1a1..6802ce8 100644
--- a/programs/main.kl
+++ b/programs/main.kl
@@ -4,7 +4,6 @@
 #load "os.kl"
 
 question_mark16 :: 0x003f
-String16 :: struct;; str: *U16; len: S64
 String32 :: struct;; str: *U32; len: S64
 UTF32_Result :: struct
   out_str: U32
diff --git a/programs/os.kl b/programs/os.kl
index 43c6e37..0e25b8b 100644
--- a/programs/os.kl
+++ b/programs/os.kl
@@ -39,6 +39,7 @@ release :: (m: *Memory)
     m.commit  = 0
     m.reserve = 0
 
+String16 :: struct;; str: *U16; len: S64
 print :: (string: String16)
   handle := GetStdHandle(STD_OUTPUT_HANDLE)
   WriteConsoleW(handle, (string.str)->*void, string.len->DWORD, 0, 0)
diff --git a/typechecking.cpp b/typechecking.cpp
index 5b458bf..926c612 100644
--- a/typechecking.cpp
+++ b/typechecking.cpp
@@ -44,7 +44,7 @@ convert_untyped_to_typed(Token *pos, Value a, Ast_Type *new_type){
 }
 
 function void
-make_sure_types_are_compatible(Token *pos, Value *a, Value *b){
+make_sure_types_are_compatible_for_constant_evaluation(Token *pos, Value *a, Value *b){
   if((is_pointer(a->type) && is_int(b->type)) || (is_pointer(b->type) && is_int(a->type))){
     return;
   }
@@ -53,7 +53,7 @@ make_sure_types_are_compatible(Token *pos, Value *a, Value *b){
   }
   else if(is_typed(a->type) && is_typed(b->type)){
     if(a->type != b->type){
-      fail: compiler_error(pos, "Type mismatch in make_sure_types_are_compatible - left: %s right: %s", docname(a->type), docname(b->type));
+      fail: compiler_error(pos, "Type mismatch in make_sure_types_are_compatible_for_constant_evaluation - left: %s right: %s", docname(a->type), docname(b->type));
     }
   }
 
@@ -78,7 +78,7 @@ compare_values(Token *pos, Token_Kind op, Value a, Value b, bool is_const){
   if(!(is_numeric(a.type) && is_numeric(b.type)))
     compiler_error(pos, "Constant application of binary %s on values of type %s and %s is not allowed", name(op), docname(a.type), docname(b.type));
 
-  make_sure_types_are_compatible(pos, &a, &b);
+  make_sure_types_are_compatible_for_constant_evaluation(pos, &a, &b);
 
   B32 result = 0;
   if(is_const){
@@ -132,7 +132,7 @@ eval_binary(Token *pos, Token_Kind op, Value a, Value b, bool is_const){
   if(!(is_numeric(a.type) && is_numeric(b.type)))
     compiler_error(pos, "Constant application of binary %s on values of type %s and %s is not allowed", name(op), docname(a.type), docname(b.type));
 
-  make_sure_types_are_compatible(pos, &a, &b);
+  make_sure_types_are_compatible_for_constant_evaluation(pos, &a, &b);
 
   Value result = {};
   result.type  = a.type;
@@ -286,6 +286,12 @@ make_sure_value_is_compatible_with_type(Token *pos, Operand *expr, Ast_Type *typ
     assert(type);
     expr->type = type;
   }
+  else if(is_void_pointer(type) && is_pointer(expr->type)){
+    expr->type = type;
+  }
+  else if(is_pointer(type) && is_void_pointer(expr->type)){
+    expr->type = type;
+  }
   else if(is_untyped(expr->type)){
     expr->value = convert_untyped_to_typed(pos, expr->value, type);
   }
@@ -723,7 +729,7 @@ resolve_field_access(Ast_Expr *node, Ast_Scope *context){
   }
 
   Ast_Type *type = decl->type;
-  if(type == type_type && is_enum(decl->type_val)) type = decl->type_val;
+  if(type == type_type && (is_enum(decl->type_val) || is_struct(decl->type_val))) type = decl->type_val;
   if(current) current->resolved_type = type;
   if(is_pointer(type)) type = type->base;
 
diff --git a/typechecking.h b/typechecking.h
index 673ddc7..fdd47bd 100644
--- a/typechecking.h
+++ b/typechecking.h
@@ -286,4 +286,5 @@ type_complete(Ast_Type *type){
 function void
 init_type(){
   type_pointer_to_char = type_pointer(type_char);
+  type_pointer_to_void = type_pointer(type_void);
 }
\ No newline at end of file
diff --git a/types.h b/types.h
index 13003e3..41bb584 100644
--- a/types.h
+++ b/types.h
@@ -198,9 +198,10 @@ global Ast_Type type__int = {TYPE_INT, sizeof(int), __alignof(int)};
 global Ast_Type *type_char  = &type__char;
 global Ast_Type *type_int  = &type__int;
 global Ast_Type *type_pointer_to_char; // Needs to be inited at runtime
+global Ast_Type *type_void  = &type__void;
+global Ast_Type *type_pointer_to_void; // Needs to be inited at runtime
 
 global Ast_Type *type_type  = &type__type;
-global Ast_Type *type_void  = &type__void;
 global Ast_Type *type_string  = &type__string;
 global Ast_Type *type_bool  = &type__bool;
 
@@ -232,6 +233,8 @@ force_inline B32 is_slice(Ast_Type *a){return a->kind == TYPE_SLICE;}
 force_inline B32 is_tuple(Ast_Type *a){return a->kind == TYPE_TUPLE;}
 force_inline B32 is_enum(Ast_Type *a){return a->kind == TYPE_ENUM;}
 force_inline B32 is_pointer(Ast_Type *a){return a->kind == TYPE_POINTER;}
+force_inline B32 is_void(Ast_Type *a){return a->kind == TYPE_VOID;}
+force_inline B32 is_void_pointer(Ast_Type *a){return a == type_pointer_to_void;}
 force_inline B32 is_string(Ast_Type *a){return a->kind == TYPE_STRING || a->kind == TYPE_UNTYPED_STRING || a == type_pointer_to_char;}
 force_inline B32 is_untyped_int(Ast_Type *a){return a->kind == TYPE_UNTYPED_INT;}
 force_inline B32 is_typed_int(Ast_Type *a){return (a->kind >= TYPE_S64 && a->kind <= TYPE_U8);}