template <class T, class... Args>
T as(Args&&... args) const; // (1)
bool as_bool() const; // (2)
template <class T>
T as_integer() const; // (3)
double as_double() const; // (4)
std::string as_string() const; // (5)
byte_string as_byte_string() const; // (6)
bignum as_bignum() const; // (7)(2) Returns true if value is bool and true, false if value is bool and false.
Otherwise throws std::runtime_exception.
(3) Returns integer value if value is integral and within range, otherwise throws std::runtime_exception.
(4) Returns floating point value if value is floating point, value cast to double if value is integral, otherwise throws std::runtime_exception.
(5) Returns value if value is string, otherwise converts value to string.