ANN: pyparsing 2.0.2 released

Paul McGuire ptmcg at
Sat Apr 19 08:44:03 CEST 2014

I'm happy to announce a new release of pyparsing, version 2.0.2. 
This release contains some small enhancements and some bugfixes.

Change summary:
- Extended "expr(name)" shortcut (same as "expr.setResultsName(name)")
  to accept "expr()" as a shortcut for "expr.copy()".

- Added "locatedExpr(expr)" helper, to decorate any returned tokens
  with their location within the input string. Adds the results names
  locn_start and locn_end to the output parse results.

- Added "pprint()" method to ParseResults, to simplify troubleshooting
  and prettified output. Now instead of importing the pprint module
  and then writing "pprint.pprint(result)", you can just write
  "result.pprint()".  This method also accepts additional positional and
  keyword arguments (such as indent, width, etc.), which get passed 
  through directly to the pprint method 

- Removed deprecation warnings when using '<<' for Forward expression
  assignment. '<<=' is still preferred, but '<<' will be retained
  for cases where '<<=' operator is not suitable (such as in defining
  lambda expressions).

- Expanded argument compatibility for classes and functions that
  take list arguments, to now accept generators as well.

- Extended list-like behavior of ParseResults, adding support for
  append and extend. NOTE: if you have existing applications using
  these names as results names, you will have to access them using
  dict-style syntax: res["append"] and res["extend"]

- ParseResults emulates the change in list vs. iterator semantics for
  methods like keys(), values(), and items(). Under Python 2.x, these
  methods will return lists, under Python 3.x, these methods will 
  return iterators.

- ParseResults now has a method haskeys() which returns True or False
  depending on whether any results names have been defined. This simplifies
  testing for the existence of results names under Python 3.x, which 
  returns keys() as an iterator, not a list.

- ParseResults now supports both list and dict semantics for pop().
  If passed no argument or an integer argument, it will use list semantics
  and pop tokens from the list of parsed tokens. If passed a non-integer
  argument (most likely a string), it will use dict semantics and 
  pop the corresponding value from any defined results names. A
  second default return value argument is supported, just as in 

- Fixed bug in markInputline, thanks for reporting this, Matt Grant!

- Cleaned up my unit test environment, now runs with Python 2.6 and 

Download pyparsing 2.0.2 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

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