Class value

docopt_value.h:31–105

A generic type to hold the various types that can be produced by docopt. This type can be one of: {bool, long, string, vector }, or empty.

	///
	/// This type can be one of: {bool, long, string, vector<string>}, or empty.
	struct value {
		/// An empty value
		value() {}

		value(std::string);
		value(std::vector<std::string>);
		
		explicit value(bool);
		explicit value(long);
		explicit value(int v) : value(static_cast<long>(v)) {}

		~value();
		value(value const&);
		value(value&&) noexcept;
		value& operator=(value const&);
		value& operator=(value&&) noexcept;

		Kind kind() const { return kind_; }
		
		// Test if this object has any contents at all
		explicit operator bool() const { return kind_ != Kind::Empty; }
		
		// Test the type contained by this value object
		bool isBool()       const { return kind_==Kind::Bool; }
		bool isString()     const { return kind_==Kind::String; }
		bool isLong()       const { return kind_==Kind::Long; }
		bool isStringList() const { return kind_==Kind::StringList; }

		// Throws std::invalid_argument if the type does not match
		bool asBool() const;
		long asLong() const;
		std::string const& asString() const;
		std::vector<std::string> const& asStringList() const;

		size_t hash() const noexcept;
		
		friend bool operator==(value const&, value const&);
		friend bool operator!=(value const&, value const&);

	private:
		union Variant {
			Variant() {}
			~Variant() {  /* do nothing; will be destroyed by ~value */ }
			
			bool boolValue;
			long longValue;
			std::string strValue;
			std::vector<std::string> strList;
		};
		
		static const char* kindAsString(Kind kind) {
			switch (kind) {
				case Kind::Empty: return "empty";
				case Kind::Bool: return "bool";
				case Kind::Long: return "long";
				case Kind::String: return "string";
				case Kind::StringList: return "string-list";
			}