48 lines
1.8 KiB
Text
48 lines
1.8 KiB
Text
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February 19, 2007
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Announcing : PLY-2.3 (Python Lex-Yacc)
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http://www.dabeaz.com/ply
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I'm pleased to announce a significant new update to PLY---a 100% Python
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implementation of the common parsing tools lex and yacc. PLY-2.3 is
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a minor bug fix release, but also features improved performance.
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If you are new to PLY, here are a few highlights:
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- PLY is closely modeled after traditional lex/yacc. If you know how
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to use these or similar tools in other languages, you will find
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PLY to be comparable.
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- PLY provides very extensive error reporting and diagnostic
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information to assist in parser construction. The original
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implementation was developed for instructional purposes. As
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a result, the system tries to identify the most common types
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of errors made by novice users.
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- PLY provides full support for empty productions, error recovery,
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precedence rules, and ambiguous grammars.
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- Parsing is based on LR-parsing which is fast, memory efficient,
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better suited to large grammars, and which has a number of nice
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properties when dealing with syntax errors and other parsing
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problems. Currently, PLY can build its parsing tables using
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either SLR or LALR(1) algorithms.
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- PLY can be used to build parsers for large programming languages.
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Although it is not ultra-fast due to its Python implementation,
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PLY can be used to parse grammars consisting of several hundred
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rules (as might be found for a language like C). The lexer and LR
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parser are also reasonably efficient when parsing normal
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sized programs.
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More information about PLY can be obtained on the PLY webpage at:
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http://www.dabeaz.com/ply
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PLY is freely available and is licensed under the terms of the Lesser
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GNU Public License (LGPL).
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Cheers,
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David Beazley (http://www.dabeaz.com)
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