Method App

develop/matchit/patterns.h:542–543

        {
        public:
            constexpr App(Unary &&unary, Pattern const &pattern)
                : mUnary{std::forward<Unary>(unary)}, mPattern{pattern} {}
            constexpr auto const &unary() const { return mUnary; }
            constexpr auto const &pattern() const { return mPattern; }