PEG基礎文法最速マスター - kmizuã®æ—¥è¨˜
Scala基礎文法最速マスターを書ã“ã†ã‹è¿·ã£ã¦ã„ãŸã‚‰ã€æ—¢ã«yuroyoroã•ã‚“ã«æ›¸ã‹ã‚Œã¦ã—ã¾ã£ãŸã®ã§ã€ã¡ã‚‡ã£ã¨é•ã†æ–¹å‘ã§ã€‚BNFã‚’æ—¢ã«çŸ¥ã£ã¦ã„る人ã¯ã€ã“れをèªã‚ã°PEGã®åŸºç¤Žã‚’マスターã—ã¦PEGを書ãã“ã¨ãŒã§ãるよã†ã«ãªã‚‹ã§ã—ょã†(ã»ã‚“ã¨ã‹ï¼Ÿ)。 基本 Parsing Expression Grammar(PEG)ã¯BNFã«ä¼¼ã¦ã„ã‚‹ã‘ã©ã€ã¡ã‚‡ã£ã¨(ã‹ãªã‚Šï¼Ÿ)é•ã†æ–‡æ³•ã®è¡¨è¨˜æ³•ã§ã™ã€‚BNFã¯ãã®æ–‡æ³•ãŒã©ã®ã‚ˆã†ãªè¨€èªžã‚’表ç¾ã—ã¦ã„ã‚‹ã‹ã‚’定ã‚ã‚‹ã®ã«å¯¾ã—ã¦ã€PEGã¯å…¥åŠ›ãŒã©ã®ã‚ˆã†ã«è§£æžã•ã‚Œã‚‹ã‹ã‚’定ã‚ã¾ã™ã€‚PEGã¨BNFã®ä¸€ç•ªå¤§ããªé•ã„ã¯ã€PEGã«ã¯æ›–昧ã•ãŒç„¡ã„ã“ã¨ã§ã™ã€‚ãŸã¨ãˆã°ã€ãƒ—ãƒã‚°ãƒ©ãƒŸãƒ³ã‚°è¨€èªžã®if文を表ç¾ã™ã‚‹æ¬¡ã®æ“¬ä¼¼BNFã«ã¯æ›–昧ã•ãŒã‚ã‚Šã¾ã™ã€‚ statement ::= if_statement | ...; if_statement ::= IF LPAREN expr RPAREN sta
PEG Parser Generator + Packrat Parserを実装ã—ã¦ã¿ãŸ - LINE ENGINEERING
詳ã—ã„解説ã¯ãƒãƒƒãƒˆä¸Šã«æ²¢å±±å˜åœ¨ã™ã‚‹ã®ã§å‰²æ„›ã—ã¾ã™ãŒã€ã”覧ã®ã‚ˆã†ã«EBNFã®è¡¨ç¾ã®ä¸€ã¤ã«ï¼ˆEBNFã¯ã„ãã¤ã‹ã®è¡¨ç¾æ–¹æ³•ãŒã‚るよã†ã§ã™ã€‚例ãˆã°ã“ã‚Œã¯W3CãŒå®šç¾©ã—ã¦ã„ã‚‹ã‚‚ã®ã§ã™ï¼‰ä¼¼ã¦ã„ã¾ã™ã€‚é•ã„ã¯å…ˆã«è¿°ã¹ãŸã‚ˆã†ã«Choiceã®åƒããŒç•°ãªã‚‹ã®ã¨ã€æ–‡æ³•ä¸Šã«å…ˆèªã¿ãŒå˜åœ¨ã™ã‚‹ã“ã¨ã§ã™ã€‚ ã“ã®PEGを使ã£ã¦å››å‰‡æ¼”ç®—ã‚’å—ç†ã™ã‚‹ã‚·ãƒ³ãƒ—ルãªãƒ«ãƒ¼ãƒ«ã‚’書ãã¨ã™ã‚‹ã¨ã€ä¾‹ãˆã°ã“ã®ã‚ˆã†ã«ãªã‚Šã¾ã™ã€‚ # expressionã‹ã‚‰ãƒ‘ースãŒå§‹ã¾ã‚‹ã¨ã™ã‚‹ expression <- additive additive <- multitive ("+" multitive / "-" multitive)* multitive <- primary ("*" primary / "/" primary)* primary <- "(" expression ")" / number number <- digit+ digit
A Meta-Grammar for PEG Parsers
This week we make the parser generator “self-hostedâ€, meaning the parser generator generates its own parser. [This is part 7 of my PEG series. See the Series Overview for the rest.] So we have a parser generator, a piece of which is a parser for grammars. We could call this a meta-parser. The meta-parser works similar to the generated parsers: GrammarParser inherits from Parser, and it uses the sa
Left-recursive PEG grammars
I’ve alluded to left-recursion as a stumbling block a few times, and it’s time to tackle it. The basic problem is that with a recursive descent parser, left-recursion causes instant death by stack overflow. [This is part 5 of my PEG series. See the Series Overview for the rest.] Consider this hypothetical grammar rule: expr: expr '+' term | termIf we were to naively translate this grammar fragment
PEG Parsers
Some years ago someone asked whether it would make sense to switch Python to a PEG parser. (Or a PEG grammar; I don’t recall exactly what was said by whom, or when.) I looked into it a bit and wasn’t sure what to think, so I dropped the subject. Recently I’ve learned more about PEG (Parsing Expression Grammars), and I now think it’s an interesting alternative to the home-grown parser generator tha
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Replacing CPython’s parser - Python Language Summit 2020
Incremental Packrat Parsing
http://web.cs.ucla.edu/~todd/research/pepm08.pdf
[PDF] Parsing Expression Grammars: A Recognition-Based Syntactic Foundation
竜 TatSu — 竜 TatSu 5.10.6 documentation
ç«œ TatSu (PEG parsers in Python) ã®ã¸ã‚ã‚ã‚‹ã© | site-hhs
PEG at the Core Developer Sprint
Implementing PEG Features
Adding actions to a PEG grammar
GitHub - we-like-parsers/pegen_experiments: Experiments for the official PEG parser generator for Python
Visualizing PEG Parsing
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