#pragma once #include #include namespace DB { /** Parse specified keyword such as SELECT or compound keyword such as ORDER BY. * All case insensitive. Requires word boundary. * For compound keywords, any whitespace characters and comments could be in the middle. */ /// Example: ORDER/* Hello */BY class ParserKeyword : public IParserBase { private: std::string_view s; public: //NOLINTNEXTLINE Want to be able to init ParserKeyword("literal") constexpr ParserKeyword(std::string_view s_): s(s_) { assert(!s.empty()); } protected: constexpr const char * getName() const override { return s.data(); } bool parseImpl(Pos & pos, ASTPtr & node, Expected & expected) override; }; class ParserToken : public IParserBase { private: TokenType token_type; public: ParserToken(TokenType token_type_) : token_type(token_type_) {} /// NOLINT protected: const char * getName() const override { return "token"; } bool parseImpl(Pos & pos, ASTPtr & /*node*/, Expected & expected) override { if (pos->type != token_type) { expected.add(pos, getTokenName(token_type)); return false; } ++pos; return true; } }; // Parser always returns true and do nothing. class ParserNothing : public IParserBase { public: const char * getName() const override { return "nothing"; } bool parseImpl(Pos & /*pos*/, ASTPtr & /*node*/, Expected & /*expected*/) override { return true; } }; }