static m_bool ptr_access(const Env env, const Exp e) {

  const m_str access = exp_access(e);

  if(!access)

    return GW_OK;

  ERR_B(e->pos, _("operand is %s"), access);

static OP_CHECK(opck_ptr_assign) {

  const Exp_Binary* bin = (Exp_Binary*)data;

  CHECK_BO(ptr_access(env, bin->lhs))

  CHECK_BO(ptr_access(env, bin->rhs))

  exp_setvar(bin->lhs, 1);

  Type t = bin->lhs->info->type;

    Type u = bin->rhs->info->type;

      const m_str str = get_type_name(env, u, 1);

      if(str && !strcmp(t->name, str))

        return bin->lhs->info->type; // use rhs?

    } while((u = u->e->parent));

  } while((t = t->e->parent));

  return env->gwion->type[et_null];

static INSTR(instr_ptr_assign) {

  POP_REG(shred, SZ_INT)

  const M_Object o = *(M_Object*)REG(0);

  *(m_uint**)o->data = *(m_uint**)REG(-SZ_INT);

  _release(o, shred);

}

static OP_CHECK(opck_ptr_deref) {

  const Exp_Unary* unary = (Exp_Unary*)data;

  DECL_ON(const m_str, str, = get_type_name(env, unary->exp->info->type, 1))

  return exp_self(unary)->info->type = nspc_lookup_type1(env->curr, insert_symbol(str));

static OP_CHECK(opck_ptr_cast) {

  const Exp_Cast* cast = (Exp_Cast*)data;

  if(!cast->td->types || !cast->td->types->td)

  DECL_ON(const Type, t, = known_type(env, cast->td))

  const Type _t = get_type(t);

  if(_t->e->def && !GET_FLAG(_t, check))

    CHECK_BN(ensure_traverse(env, _t))

  const Type to = known_type(env, cast->td->types->td);

  if(isa(cast->exp->info->type, to) > 0)

    return t;

  ERR_N(exp_self(cast)->pos, "invalid pointer cast")

static OP_CHECK(opck_ptr_implicit) {

  const struct Implicit* imp = (struct Implicit*)data;

  const Exp e = imp->e;

  DECL_OO(const m_str, name, = get_type_name(env, imp->t, 1))

  if(!strcmp(get_type_name(env, imp->t, 1), e->info->type->name)) {

    const m_str access = exp_access(e);

    if(access)

      ERR_N(e->pos, _("can't cast %s value to Ptr"), access);

    e->info->cast_to = imp->t;

    exp_setvar(e, 1);

    const Type t = get_type(imp->t);

    if(!GET_FLAG(t, check))

      CHECK_BN(traverse_class_def(env, t->e->def))

    return imp->t;

static INSTR(instr_ptr_deref) {

  const M_Object o = *(M_Object*)REG(-SZ_INT);

  if(!*(m_bit**)o->data)

    Except(shred, _("EmptyPointerException"));

  if(instr->m_val2)

    memcpy(REG(-SZ_INT), o->data, SZ_INT);

    shred->reg -= SZ_INT - instr->m_val;

    memcpy(REG(-instr->m_val), *(m_bit**)o->data, instr->m_val);

static INSTR(Cast2Ptr) {

  const M_Object o = new_object(shred->info->mp, shred, (Type)instr->m_val);

  *(m_uint**)o->data = *(m_uint**)REG(-SZ_INT);

  *(M_Object*)REG(-SZ_INT) = o;

}

static OP_EMIT(opem_ptr_cast) {

  const Exp_Cast* cast = (Exp_Cast*)data;

  const Instr instr = emit_add_instr(emit, Cast2Ptr);

  instr->m_val = (m_uint)exp_self(cast)->info->type;

  return instr;

static OP_EMIT(opem_ptr_implicit) {

  const struct Implicit* imp = (struct Implicit*)data;

  const Instr instr = emit_add_instr(emit, Cast2Ptr);

  instr->m_val = (m_uint)imp->t;

  return instr;

static OP_EMIT(opem_ptr_deref) {

  const Exp_Unary* unary = (Exp_Unary*)data;

  const Instr instr = emit_add_instr(emit, instr_ptr_deref);

  instr->m_val = exp_self(unary)->info->type->size;

  instr->m_val2 = exp_getvar(exp_self(unary));

  return instr;

static DTOR(ptr_object_dtor) {

  release(*(M_Object*)o->data, shred);

}

static OP_CHECK(opck_ptr_scan) {

  struct TemplateScan *ts = (struct TemplateScan*)data;

  const Type t = (Type)scan_class(env, ts->t, ts->td);

  const Type base = known_type(env, t->e->def->base.tmpl->call->td);

  if(isa(base, env->gwion->type[et_compound]) > 0 && !t->nspc->dtor) {

    t->nspc->dtor = new_vm_code(env->gwion->mp, NULL, SZ_INT, ae_flag_member | ae_flag_builtin, "@PtrDtor");

    if(!GET_FLAG(t, struct))

      t->nspc->dtor->native_func = (m_uint)ptr_object_dtor;

    SET_FLAG(t, dtor);

  return t;

GWION_IMPORT(ptr) {

  const Type _t_ptr = gwi_class_ini(gwi, "@Ptr", NULL);

  GWI_BB(gwi_class_end(gwi))

  SET_FLAG(_t_ptr, unary);

  GWI_BB(gwi_oper_ini(gwi, "@Ptr", NULL, NULL))

  GWI_BB(gwi_oper_add(gwi, opck_ptr_scan))

  GWI_BB(gwi_oper_end(gwi, "@scan", NULL))

  const Type t_ptr = gwi_class_ini(gwi, "Ptr<~A~>", "@Ptr");

  gwi->gwion->type[et_ptr] = t_ptr;

  GWI_BB(gwi_item_ini(gwi, "@internal", "@val"))

  GWI_BB(gwi_item_end(gwi, 0, NULL))

  GWI_BB(gwi_class_end(gwi))

  SET_FLAG(t_ptr, unary);

  GWI_BB(gwi_oper_ini(gwi, (m_str)OP_ANY_TYPE, "nonnull Ptr", NULL))

  GWI_BB(gwi_oper_add(gwi, opck_ptr_assign))

  GWI_BB(gwi_oper_end(gwi, ":=>", instr_ptr_assign))

  GWI_BB(gwi_oper_add(gwi, opck_ptr_implicit))

  GWI_BB(gwi_oper_emi(gwi, opem_ptr_implicit))

  GWI_BB(gwi_oper_end(gwi, "@implicit", Cast2Ptr))

  GWI_BB(gwi_oper_add(gwi, opck_ptr_cast))

  GWI_BB(gwi_oper_emi(gwi, opem_ptr_cast))

  GWI_BB(gwi_oper_end(gwi, "$", Cast2Ptr))

  GWI_BB(gwi_oper_ini(gwi, NULL, "nonnull Ptr", NULL))

  GWI_BB(gwi_oper_add(gwi, opck_ptr_deref))

  GWI_BB(gwi_oper_emi(gwi, opem_ptr_deref))

  GWI_BB(gwi_oper_end(gwi, "*", instr_ptr_deref))

  return GW_OK;