Method validate

CvPlot/ext/catch2/inc/catch.hpp:9142–9142

    public:
        virtual ~ParserBase() = default;
        virtual auto validate() const -> Result { return Result::ok(); }
        virtual auto parse( std::string const& exeName, TokenStream const &tokens) const -> InternalParseResult  = 0;
        virtual auto cardinality() const -> size_t { return 1; }