option.h

#pragma once
namespace stingray_plugin_foundation {
    // A class that can optionally hold a value.
    template <class T>
    class Option
    {
        bool _has_value;
        T _value;
        Option(bool has_value, const T &value) : _has_value(has_value), _value(value) {}
    public:
        // Initializes the object to hold no value.
        Option() : _has_value(false), _value() {}
        // Initializes the object to hold the specified value.
        Option(const T &value) : _has_value(true), _value(value) {}
        // Static constructor that returns an Option<T> object with no value.
        static Option<T> none() {return Option<T>();}
        // Static constructor that returns an Option<T> object with the specified value.
        static Option<T> some(const T &value) {return Option<T>(true, value);}
        // True if the object has a value.
        bool is_some() const {return _has_value;}
        // True if the object doesn't have a value.
        bool is_none() const {return !_has_value;}
        // Returns the object's value.
        const T &value() const {
            XASSERT(is_some(), "Cannot obtain value from a none Option<T>.");
            return _value;
        }
    };
}