Class Val

crates/c-api/include/wasm.hh:502–586

// Values

class Val {
  ValKind kind_;
  union impl {
    int32_t i32;
    int64_t i64;
    float32_t f32;
    float64_t f64;
    Ref* ref;
  } impl_;

  Val(ValKind kind, impl impl) : kind_(kind), impl_(impl) {}

public:
  Val() : kind_(ValKind::EXTERNREF) { impl_.ref = nullptr; }
  explicit Val(int32_t i) : kind_(ValKind::I32) { impl_.i32 = i; }
  explicit Val(int64_t i) : kind_(ValKind::I64) { impl_.i64 = i; }
  explicit Val(float32_t z) : kind_(ValKind::F32) { impl_.f32 = z; }
  explicit Val(float64_t z) : kind_(ValKind::F64) { impl_.f64 = z; }
  explicit Val(own<Ref>&& r) : kind_(ValKind::EXTERNREF) { impl_.ref = r.release(); }

  Val(Val&& that) : kind_(that.kind_), impl_(that.impl_) {
    if (is_ref()) that.impl_.ref = nullptr;
  }

  ~Val() {
    reset();
  }

  auto is_num() const -> bool { return wasm::is_num(kind_); }
  auto is_ref() const -> bool { return wasm::is_ref(kind_); }

  static auto i32(int32_t x) -> Val { return Val(x); }
  static auto i64(int64_t x) -> Val { return Val(x); }
  static auto f32(float32_t x) -> Val { return Val(x); }
  static auto f64(float64_t x) -> Val { return Val(x); }
  static auto ref(own<Ref>&& x) -> Val { return Val(std::move(x)); }
  template<class T> inline static auto make(T x) -> Val;
  template<class T> inline static auto make(own<T>&& x) -> Val;

  void reset() {
    if (is_ref() && impl_.ref) {
      destroyer()(impl_.ref);
      impl_.ref = nullptr;
    }
  }

  void reset(Val& that) {
    reset();
    kind_ = that.kind_;
    impl_ = that.impl_;
    if (is_ref()) that.impl_.ref = nullptr;
  }

  auto operator=(Val&& that) -> Val& {
    reset(that);
    return *this;
  }