ANN: pyparsing 1.5.6 released!


Paul McGuire

After about 10 months, there is a new release of pyparsing, version
1.5.6. This release contains some small enhancements, some bugfixes,
and some new examples.

Most notably, this release includes the first public release of the
Verilog parser. I have tired of restricting this parser for
commercial use, and so I am distributing it under the same license as
pyparsing, with the request that if you use it for commmercial use,
please make a commensurate donation to your local Red Cross.

Change summary:
- Cleanup of parse action normalizing code, to be more version-
and robust in the face of future Python versions - much thanks to
Raymond Hettinger for this rewrite!

- Removal of exception cacheing, addressing a memory leak condition
in Python 3. Thanks to Michael Droettboom and the Cape Town PUG for
their analysis and work on this problem!

- Fixed bug when using packrat parsing, where a previously parsed
expression would duplicate subsequent tokens - reported by Frankie
Ribery on stackoverflow, thanks!

- Added 'ungroup' helper method, to address token grouping done
implicitly by And expressions, even if only one expression in the
And actually returns any text - also inspired by stackoverflow
discussion with Frankie Ribery!

- Fixed bug in srange, which accepted escaped hex characters of the
form '\0x##', but should be '\x##'. Both forms will be supported
for backwards compatibility.

- Enhancement to countedArray, accepting an optional expression to be
used for matching the leading integer count - proposed by Mathias on
the pyparsing mailing list, good idea!

- Added the Verilog parser to the provided set of examples, under the
MIT license. While this frees up this parser for any use, if you
yourself using it in a commercial purpose, please consider making a
charitable donation as described in the parser's header.

- Added the excludeChars argument to the Word class, to simplify
a word composed of all characters in a large range except for one or
two. Suggested by JesterEE on the pyparsing wiki.

- Added optional overlap parameter to scanString, to return
matches found in the source text.

- Updated oneOf internal regular expression generation, with improved
parse time performance.

- Slight performance improvement in transformString, removing empty
strings from the list of string fragments built while scanning the
source text, before calling ''.join. Especially useful when using
transformString to strip out selected text.

- Enhanced form of using the "expr('name')" style of results naming,
in lieu of calling setResultsName. If name ends with an '*', then
this is equivalent to

- Fixed up internal list flattener to use iteration instead of
to avoid stack overflow when transforming large files.

- Added other new examples:
. protobuf parser - parses Google's protobuf language
. btpyparse - a BibTex parser contributed by Matthew Brett,
with test suite (thanks, Matthew!)
. - demo using trailing '*' for results

Download pyparsing 1.5.6 at,
or use 'easy_install pyparsing'. You can also access pyparsing's
epydoc documentation online at

The pyparsing Wiki is at

-- Paul

Pyparsing is a pure-Python class library for quickly developing
recursive-descent parsers. Parser grammars are assembled directly in
the calling Python code, using classes such as Literal, Word,
OneOrMore, Optional, etc., combined with operators '+', '|', and '^'
for And, MatchFirst, and Or. No separate code-generation or external
files are required. Pyparsing can be used in many cases in place of
regular expressions, with shorter learning curve and greater
readability and maintainability. Pyparsing comes with a number of
parsing examples, including:
- "Hello, World!" (English, Korean, Greek, and Spanish(new))
- chemical formulas
- Verilog parser
- Google protobuf parser
- time expression parser/evaluator
- configuration file parser
- web page URL extractor
- 5-function arithmetic expression parser
- subset of CORBA IDL
- chess portable game notation
- simple SQL parser
- Mozilla calendar file parser
- EBNF parser/compiler
- Python value string parser (lists, dicts, tuples, with nesting)
(safe alternative to eval)
- HTML tag stripper
- S-expression parser
- macro substitution preprocessor



Waldek M.

Dnia Thu, 30 Jun 2011 23:09:18 -0700 (PDT), Paul McGuire napisa³(a):
After about 10 months, there is a new release of pyparsing, version
1.5.6. This release contains some small enhancements, some bugfixes,
and some new examples.

Thanks! That is great news.

I'm not using pyparsing right now, but I used to and surely
will. I just wish it was included in the standard Python distribution
some day...

Best regards,

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