Parser.cpp 6.7 KB

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  1. /*
  2. * Copyright (c) 2021, Tim Flynn <trflynn89@pm.me>
  3. * All rights reserved.
  4. *
  5. * Redistribution and use in source and binary forms, with or without
  6. * modification, are permitted provided that the following conditions are met:
  7. *
  8. * 1. Redistributions of source code must retain the above copyright notice, this
  9. * list of conditions and the following disclaimer.
  10. *
  11. * 2. Redistributions in binary form must reproduce the above copyright notice,
  12. * this list of conditions and the following disclaimer in the documentation
  13. * and/or other materials provided with the distribution.
  14. *
  15. * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  16. * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  17. * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  18. * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
  19. * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  20. * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  21. * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  22. * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  23. * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  24. * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25. */
  26. #include "Parser.h"
  27. namespace SQL {
  28. Parser::Parser(Lexer lexer)
  29. : m_parser_state(move(lexer))
  30. {
  31. }
  32. NonnullRefPtr<Statement> Parser::next_statement()
  33. {
  34. switch (m_parser_state.m_token.type()) {
  35. case TokenType::Create:
  36. return parse_create_table_statement();
  37. case TokenType::Drop:
  38. return parse_drop_table_statement();
  39. default:
  40. expected("CREATE or DROP");
  41. return create_ast_node<ErrorStatement>();
  42. }
  43. }
  44. NonnullRefPtr<CreateTable> Parser::parse_create_table_statement()
  45. {
  46. // https://sqlite.org/lang_createtable.html
  47. consume(TokenType::Create);
  48. bool is_temporary = false;
  49. if (consume_if(TokenType::Temp) || consume_if(TokenType::Temporary))
  50. is_temporary = true;
  51. consume(TokenType::Table);
  52. bool is_error_if_table_exists = true;
  53. if (consume_if(TokenType::If)) {
  54. consume(TokenType::Not);
  55. consume(TokenType::Exists);
  56. is_error_if_table_exists = false;
  57. }
  58. String schema_or_table_name = consume(TokenType::Identifier).value();
  59. String schema_name;
  60. String table_name;
  61. if (consume_if(TokenType::Period)) {
  62. schema_name = move(schema_or_table_name);
  63. table_name = consume(TokenType::Identifier).value();
  64. } else {
  65. table_name = move(schema_or_table_name);
  66. }
  67. // FIXME: Parse "AS select-stmt".
  68. NonnullRefPtrVector<ColumnDefinition> column_definitions;
  69. consume(TokenType::ParenOpen);
  70. do {
  71. column_definitions.append(parse_column_definition());
  72. if (match(TokenType::ParenClose))
  73. break;
  74. consume(TokenType::Comma);
  75. } while (!match(TokenType::Eof));
  76. // FIXME: Parse "table-constraint".
  77. consume(TokenType::ParenClose);
  78. consume(TokenType::SemiColon);
  79. return create_ast_node<CreateTable>(move(schema_name), move(table_name), move(column_definitions), is_temporary, is_error_if_table_exists);
  80. }
  81. NonnullRefPtr<DropTable> Parser::parse_drop_table_statement()
  82. {
  83. // https://sqlite.org/lang_droptable.html
  84. consume(TokenType::Drop);
  85. consume(TokenType::Table);
  86. bool is_error_if_table_does_not_exist = true;
  87. if (consume_if(TokenType::If)) {
  88. consume(TokenType::Exists);
  89. is_error_if_table_does_not_exist = false;
  90. }
  91. String schema_or_table_name = consume(TokenType::Identifier).value();
  92. String schema_name;
  93. String table_name;
  94. if (consume_if(TokenType::Period)) {
  95. schema_name = move(schema_or_table_name);
  96. table_name = consume(TokenType::Identifier).value();
  97. } else {
  98. table_name = move(schema_or_table_name);
  99. }
  100. consume(TokenType::SemiColon);
  101. return create_ast_node<DropTable>(move(schema_name), move(table_name), is_error_if_table_does_not_exist);
  102. }
  103. NonnullRefPtr<ColumnDefinition> Parser::parse_column_definition()
  104. {
  105. // https://sqlite.org/syntax/column-def.html
  106. auto name = consume(TokenType::Identifier).value();
  107. auto type_name = match(TokenType::Identifier)
  108. ? parse_type_name()
  109. // https://www.sqlite.org/datatype3.html: If no type is specified then the column has affinity BLOB.
  110. : create_ast_node<TypeName>("BLOB", NonnullRefPtrVector<SignedNumber> {});
  111. // FIXME: Parse "column-constraint".
  112. return create_ast_node<ColumnDefinition>(move(name), move(type_name));
  113. }
  114. NonnullRefPtr<TypeName> Parser::parse_type_name()
  115. {
  116. // https: //sqlite.org/syntax/type-name.html
  117. auto name = consume(TokenType::Identifier).value();
  118. NonnullRefPtrVector<SignedNumber> signed_numbers;
  119. if (consume_if(TokenType::ParenOpen)) {
  120. signed_numbers.append(parse_signed_number());
  121. if (consume_if(TokenType::Comma))
  122. signed_numbers.append(parse_signed_number());
  123. consume(TokenType::ParenClose);
  124. }
  125. return create_ast_node<TypeName>(move(name), move(signed_numbers));
  126. }
  127. NonnullRefPtr<SignedNumber> Parser::parse_signed_number()
  128. {
  129. // https://sqlite.org/syntax/signed-number.html
  130. bool is_positive = true;
  131. if (consume_if(TokenType::Plus))
  132. is_positive = true;
  133. else if (consume_if(TokenType::Minus))
  134. is_positive = false;
  135. if (match(TokenType::NumericLiteral)) {
  136. auto number = consume(TokenType::NumericLiteral).double_value();
  137. return create_ast_node<SignedNumber>(is_positive ? number : (number * -1));
  138. }
  139. expected("NumericLiteral");
  140. return create_ast_node<SignedNumber>(0);
  141. }
  142. Token Parser::consume()
  143. {
  144. auto old_token = m_parser_state.m_token;
  145. m_parser_state.m_token = m_parser_state.m_lexer.next();
  146. return old_token;
  147. }
  148. Token Parser::consume(TokenType expected_type)
  149. {
  150. if (!match(expected_type)) {
  151. expected(Token::name(expected_type));
  152. }
  153. return consume();
  154. }
  155. bool Parser::consume_if(TokenType expected_type)
  156. {
  157. if (!match(expected_type))
  158. return false;
  159. consume();
  160. return true;
  161. }
  162. bool Parser::match(TokenType type) const
  163. {
  164. return m_parser_state.m_token.type() == type;
  165. }
  166. void Parser::expected(StringView what)
  167. {
  168. syntax_error(String::formatted("Unexpected token {}, expected {}", m_parser_state.m_token.name(), what));
  169. }
  170. void Parser::syntax_error(String message)
  171. {
  172. m_parser_state.m_errors.append({ move(message), position() });
  173. }
  174. Parser::Position Parser::position() const
  175. {
  176. return {
  177. m_parser_state.m_token.line_number(),
  178. m_parser_state.m_token.line_column()
  179. };
  180. }
  181. Parser::ParserState::ParserState(Lexer lexer)
  182. : m_lexer(move(lexer))
  183. , m_token(m_lexer.next())
  184. {
  185. }
  186. }