Packrat Parsers Can Support Multiple Left-recursive Calls at the Same Position

• Item type: Trans(1)
• 公開日: 2021-01-27
• タイトル: Packrat Parsers Can Support Multiple Left-recursive Calls at the Same Position
• タイトル / 言語: en
• タイトル: Packrat Parsers Can Support Multiple Left-recursive Calls at the Same Position
• 言語: eng
• キーワード / 主題Scheme: Other
• キーワード / 主題: [通常論文] PEG, packrat parser, left recursion, memoization
• 資源タイプ / 資源タイプ識別子: http://purl.org/coar/resource_type/c_6501
• 資源タイプ: journal article
• 著者所属: Graduate School of Science and Technology Degree Programs in Systems and Information Engineering Master's Program in Computer Science, University of Tsukuba
• 著者所属: Department of Information Engineering, Faculty of Engineering, Information and Systems, University of Tsukuba
• 著者所属(英): en
• 著者所属(英): Graduate School of Science and Technology Degree Programs in Systems and Information Engineering Master's Program in Computer Science, University of Tsukuba
• 著者所属(英): en
• 著者所属(英): Department of Information Engineering, Faculty of Engineering, Information and Systems, University of Tsukuba
• 著者名: Masaki, Umeda; Atusi, Maeda
• 著者名(英): Masaki, Umeda; Atusi, Maeda
• 論文抄録 / 内容記述タイプ: Other
• 論文抄録 / 内容記述: One of the common problems with the recursive descent parsing method is that when parsing with a left-recursive grammar, the parsing does not terminate because the same parsing function is recursively invoked indefinitely without consuming the input string. Packrat parsing, which is a variant of recursive descent parsing method that handles grammars described in parsing expression grammars (PEGs) by backtracking, is also affected by the above problem. Although naive backtracking parsers may exhibit an exponential execution time, packrat parsers achieve a linear time complexity (for grammars that are not left-recursive) by memoizing the result of each call to the parsing functions. Some methods have been proposed to solve the problem of left recursion in packrat parsers. In these methods, memoization tables in packrat parsers are modified to limit the depth of the recursive calls. By calling the same parsing function repeatedly while increasing the limit, the parsed range in the input string is expanded gradually. These methods have problems in that multiple occurences of left-recursive calls at the same input position cannot be handled correctly, and some of the grammars that does not include left recursion cannot be handled. In this research, we propose and implement a new packrat parser to address these problems. This packrat parser can handle multiple occurences of left-recursive calls at the same position in the input by giving priority to the most recently used rule when gradually increasing the parsed range of the recursion. In the evaluation of the proposed method, in addition to the grammars including left recursion manageable by the methods proposed in existing studies, we confirmed that our approach supports the grammars that cannot be handled by those existing methods.; ------------------------------; This is a preprint of an article intended for publication Journal of; Information Processing(JIP). This preprint should not be cited. This; article should be cited as: Journal of Information Processing Vol.29(2021) (online); ------------------------------
• 論文抄録(英) / 内容記述タイプ: Other
• 論文抄録(英) / 内容記述: One of the common problems with the recursive descent parsing method is that when parsing with a left-recursive grammar, the parsing does not terminate because the same parsing function is recursively invoked indefinitely without consuming the input string. Packrat parsing, which is a variant of recursive descent parsing method that handles grammars described in parsing expression grammars (PEGs) by backtracking, is also affected by the above problem. Although naive backtracking parsers may exhibit an exponential execution time, packrat parsers achieve a linear time complexity (for grammars that are not left-recursive) by memoizing the result of each call to the parsing functions. Some methods have been proposed to solve the problem of left recursion in packrat parsers. In these methods, memoization tables in packrat parsers are modified to limit the depth of the recursive calls. By calling the same parsing function repeatedly while increasing the limit, the parsed range in the input string is expanded gradually. These methods have problems in that multiple occurences of left-recursive calls at the same input position cannot be handled correctly, and some of the grammars that does not include left recursion cannot be handled. In this research, we propose and implement a new packrat parser to address these problems. This packrat parser can handle multiple occurences of left-recursive calls at the same position in the input by giving priority to the most recently used rule when gradually increasing the parsed range of the recursion. In the evaluation of the proposed method, in addition to the grammars including left recursion manageable by the methods proposed in existing studies, we confirmed that our approach supports the grammars that cannot be handled by those existing methods.; ------------------------------; This is a preprint of an article intended for publication Journal of; Information Processing(JIP). This preprint should not be cited. This; article should be cited as: Journal of Information Processing Vol.29(2021) (online); ------------------------------
• 書誌レコードID / 収録物識別子タイプ: NCID
• 書誌レコードID / 収録物識別子: AA11464814
• 書誌情報: 情報処理学会論文誌プログラミング（PRO）; 巻 14, 号 1, 発行日 2021-01-27
• ISSN / 収録物識別子タイプ: ISSN
• ISSN / 収録物識別子: 1882-7802
• 出版者 / 言語: ja
• 出版者: 情報処理学会