vm/tagged.hpp

   1 namespace factor
   2 {
   3
   4 template<typename Type> cell tag(Type *value)
   5 {
   6         return RETAG(value,Type::type_number);
   7 }
   8
   9 inline static cell tag_dynamic(object *value)
  10 {
  11         return RETAG(value,value->type());
  12 }
  13
  14 template<typename Type>
  15 struct tagged
  16 {
  17         cell value_;
  18
  19         cell type() const
  20         {
  21                 return TAG(value_);
  22         }
  23
  24         bool type_p(cell type_) const
  25         {
  26                 return type() == type_;
  27         }
  28
  29         bool type_p() const
  30         {
  31                 if(Type::type_number == TYPE_COUNT)
  32                         return true;
  33                 else
  34                         return type_p(Type::type_number);
  35         }
  36
  37         cell value() const
  38         {
  39 #ifdef FACTOR_DEBUG
  40                 assert(type_p());
  41 #endif
  42                 return value_;
  43         }
  44
  45         Type *untagged() const
  46         {
  47 #ifdef FACTOR_DEBUG
  48                 assert(type_p());
  49 #endif
  50                 return (Type *)(UNTAG(value_));
  51         }
  52
  53         Type *untag_check(factor_vm *parent) const
  54         {
  55                 if(!type_p())
  56                         parent->type_error(Type::type_number,value_);
  57                 return untagged();
  58         }
  59
  60         explicit tagged(cell tagged) : value_(tagged) {}
  61         explicit tagged(Type *untagged) : value_(factor::tag(untagged)) {}
  62
  63         Type *operator->() const { return untagged(); }
  64         cell *operator&() const { return &value_; }
  65
  66         const tagged<Type> &operator=(const Type *x) { value_ = tag(x); return *this; }
  67         const tagged<Type> &operator=(const cell &x) { value_ = x; return *this; }
  68
  69         bool operator==(const tagged<Type> &x) { return value_ == x.value_; }
  70         bool operator!=(const tagged<Type> &x) { return value_ != x.value_; }
  71
  72         template<typename NewType> tagged<NewType> as() { return tagged<NewType>(value_); }
  73 };
  74
  75 template<typename Type> Type *factor_vm::untag_check(cell value)
  76 {
  77         return tagged<Type>(value).untag_check(this);
  78 }
  79
  80 template<typename Type> Type *untag(cell value)
  81 {
  82         return tagged<Type>(value).untagged();
  83 }
  84
  85 }