change `PY_NULL` into `nullptr`

include/pocketpy/common.h

@@ -182,7 +182,7 @@ struct const_sso_var {};
 
 struct PyVar final{
     Type type;
-    bool is_sso;
+    bool is_ptr;
     uint8_t flags;
     // 12 bytes SSO
     int _0; i64 _1;
@@ -192,14 +192,14 @@ struct PyVar final{
 
     /* We must initialize all members to allow == operator to work correctly */
     // constexpr initialized
-    constexpr PyVar(const const_sso_var&, Type type, int value): type(type), is_sso(true), flags(0), _0(value), _1(0) {}
+    constexpr PyVar(const const_sso_var&, Type type, int value): type(type), is_ptr(false), flags(0), _0(value), _1(0) {}
     // zero initialized
-    constexpr PyVar(std::nullptr_t): type(0), is_sso(false), flags(0), _0(0), _1(0) {}
+    constexpr PyVar(std::nullptr_t): type(0), is_ptr(false), flags(0), _0(0), _1(0) {}
     // PyObject* initialized (is_sso = false)
-    PyVar(Type type, PyObject* p): type(type), is_sso(false), flags(0), _0(0), _1(reinterpret_cast<i64>(p)) {}
+    PyVar(Type type, PyObject* p): type(type), is_ptr(true), flags(0), _0(0), _1(reinterpret_cast<i64>(p)) {}
     // SSO initialized (is_sso = true)
     template<typename T>
-    PyVar(Type type, T value): type(type), is_sso(true), flags(0), _0(0), _1(0) {
+    PyVar(Type type, T value): type(type), is_ptr(false), flags(0), _0(0), _1(0) {
         static_assert(sizeof(T) <= 12, "SSO size exceeded");
         as<T>() = value;
     }

include/pocketpy/obj.h

@@ -153,7 +153,7 @@ inline constexpr int py_sizeof = PyObject::FIXED_SIZE + sizeof(T);
 const int kTpIntIndex = 3;
 const int kTpFloatIndex = 4;
 
-inline bool is_tagged(PyVar p) noexcept { return p.is_sso; }
+inline bool is_tagged(PyVar p) noexcept { return !p.is_ptr; }
 inline bool is_float(PyVar p) noexcept { return p.type.index == kTpFloatIndex; }
 inline bool is_int(PyVar p) noexcept { return p.type.index == kTpIntIndex; }
 
@@ -189,7 +189,7 @@ obj_get_t<T> PyVar::obj_get(){
 }
 
 #define PK_OBJ_GET(T, obj) (obj).obj_get<T>()
-#define PK_OBJ_MARK(obj) if(!is_tagged(obj)) vm->__obj_gc_mark(obj.get());
+#define PK_OBJ_MARK(obj) if((obj).is_ptr) vm->__obj_gc_mark(obj.get());
 
 #define VAR(x) py_var(vm, x)
 #define CAST(T, x) py_cast<T>(vm, x)
@@ -207,7 +207,7 @@ inline bool try_cast_int(PyVar obj, i64* val) noexcept {
     return false;
 }
 
-extern PyVar const PY_NULL;
+#define PY_NULL nullptr
 extern PyVar const PY_OP_CALL;
 extern PyVar const PY_OP_YIELD;
 

src/codeobject.cpp

@@ -7,7 +7,6 @@ namespace pkpy{
             blocks.push_back(CodeBlock(CodeBlockType::NO_BLOCK, -1, 0, 0));
         }
 
-    PyVar const PY_NULL(Type(), new PyObject(Type()));
     PyVar const PY_OP_CALL(Type(), new PyObject(Type()));
     PyVar const PY_OP_YIELD(Type(), new PyObject(Type()));
 }   // namespace pkpy