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CVS Commit History:
2012-11-23 23:33:55 by othyro | Files touched by this commit (43) |
Log message:
Mostly whitespace and blank line fixing. Some files also got minor
formatting corrections as well as other corrections.
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2012-10-07 15:57:25 by Aleksej Saushev | Files touched by this commit (211) |
Log message:
Drop superfluous PKG_DESTDIR_SUPPORT, "user-destdir" is default these days.
Mark packages that don't or might probably not have staged installation.
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2010-08-04 18:15:27 by URA Hiroshi | Files touched by this commit (4) | |
Log message:
Import PLY-3.3 as wip/py-ply.
PLY is a 100% Python implementation of the common parsing tools lex
and yacc. Here are a few highlights:
- PLY is very closely modeled after traditional lex/yacc.
If you know how to use these tools in C, you will find PLY
to be similar.
- PLY provides *very* extensive error reporting and diagnostic
information to assist in parser construction. The original
implementation was developed for instructional purposes. As
a result, the system tries to identify the most common types
of errors made by novice users.
- PLY provides full support for empty productions, error recovery,
precedence specifiers, and moderately ambiguous grammars.
- Parsing is based on LR-parsing which is fast, memory efficient,
better suited to large grammars, and which has a number of nice
properties when dealing with syntax errors and other parsing problems.
Currently, PLY builds its parsing tables using the LALR(1)
algorithm used in yacc.
- PLY uses Python introspection features to build lexers and parsers.
This greatly simplifies the task of parser construction since it reduces
the number of files and eliminates the need to run a separate lex/yacc
tool before running your program.
- PLY can be used to build parsers for "real" programming languages.
Although it is not ultra-fast due to its Python implementation,
PLY can be used to parse grammars consisting of several hundred
rules (as might be found for a language like C). The lexer and LR
parser are also reasonably efficient when parsing typically
sized programs. People have used PLY to build parsers for
C, C++, ADA, and other real programming languages.
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