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==========
Change Log
==========

Version 2.4.7 - March, 2020
---------------------------
- Backport of selected fixes from 3.0.0 work:
  . Each bug with Regex expressions
  . And expressions not properly constructing with generator
  . Traceback abbreviation
  . Bug in delta_time example
  . Fix regexen in pyparsing_common.real and .sci_real
  . Avoid FutureWarning on Python 3.7 or later
  . Cleanup output in runTests if comments are embedded in test string

Version 2.4.6 - December, 2019
------------------------------
- Fixed typos in White mapping of whitespace characters, to use
  correct "\u" prefix instead of "u\".

- Fix bug in left-associative ternary operators defined using
  infixNotation. First reported on StackOverflow by user Jeronimo.

- Backport of pyparsing_test namespace from 3.0.0, including
  TestParseResultsAsserts mixin class defining unittest-helper
  methods:
  . def assertParseResultsEquals(
            self, result, expected_list=None, expected_dict=None, msg=None)
  . def assertParseAndCheckList(
            self, expr, test_string, expected_list, msg=None, verbose=True)
  . def assertParseAndCheckDict(
            self, expr, test_string, expected_dict, msg=None, verbose=True)
  . def assertRunTestResults(
            self, run_tests_report, expected_parse_results=None, msg=None)
  . def assertRaisesParseException(self, exc_type=ParseException, msg=None)

To use the methods in this mixin class, declare your unittest classes as:

from pyparsing import pyparsing_test as ppt
    class MyParserTest(ppt.TestParseResultsAsserts, unittest.TestCase):
        ...

Version 2.4.5 - November, 2019
------------------------------
- Fixed encoding when setup.py reads README.rst to include the
  project long description when uploading to PyPI. A stray
  unicode space in README.rst prevented the source install on
  systems whose default encoding is not 'utf-8'.

Version 2.4.4 - November, 2019
--------------------------------
- Unresolved symbol reference in 2.4.3 release was masked by stdout
  buffering in unit tests, thanks for the prompt heads-up, Ned 
  Batchelder!

Version 2.4.3 - November, 2019
------------------------------
- Fixed a bug in ParserElement.__eq__ that would for some parsers
  create a recursion error at parser definition time. Thanks to
  Michael Clerx for the assist. (Addresses issue #123)

- Fixed bug in indentedBlock where a block that ended at the end
  of the input string could cause pyaprsing to loop forever. Raised
  as part of discussion on StackOverflow with geckos.

- Backports from pyparsing 3.0.0:
  . __diag__.enable_all_warnings()
  . Fixed bug in PrecededBy which caused infinite recursion, issue #127
  . support for using regex-compiled RE to construct Regex expressions

Version 2.4.2 - July, 2019
--------------------------
- Updated the shorthand notation that has been added for repetition
  expressions: expr[min, max], with '...' valid as a min or max value:
     - expr[...] and expr[0, ...] are equivalent to ZeroOrMore(expr)
     - expr[1, ...] is equivalent to OneOrMore(expr)
     - expr[n, ...] or expr[n,] is equivalent
          to expr*n + ZeroOrMore(expr)
          (read as "n or more instances of expr")
     - expr[..., n] is equivalent to expr*(0, n)
     - expr[m, n] is equivalent to expr*(m, n)
  Note that expr[..., n] and expr[m, n] do not raise an exception
  if more than n exprs exist in the input stream.  If this
  behavior is desired, then write expr[..., n] + ~expr.

Better interpretation of [...] as ZeroOrMore raised by crowsonkb,
  thanks for keeping me in line!

If upgrading from 2.4.1 or 2.4.1.1 and you have used `expr[...]`
  for `OneOrMore(expr)`, it must be updated to `expr[1, ...]`.

- The defaults on all the `__diag__` switches have been set to False,
  to avoid getting alarming warnings. To use these diagnostics, set
  them to True after importing pyparsing.

Example:

import pyparsing as pp
      pp.__diag__.warn_multiple_tokens_in_named_alternation = True

- Fixed bug introduced by the use of __getitem__ for repetition,
  overlooking Python's legacy implementation of iteration
  by sequentially calling __getitem__ with increasing numbers until
  getting an IndexError. Found during investigation of problem
  reported by murlock, merci!

Version 2.4.2a1 - July, 2019
----------------------------
It turns out I got the meaning of `[...]` absolutely backwards,
so I've deleted 2.4.1 and am repushing this release as 2.4.2a1
for people to give it a try before I can call it ready to go.

The `expr[...]` notation was pushed out to be synonymous with
`OneOrMore(expr)`, but this is really counter to most Python
notations (and even other internal pyparsing notations as well).
It should have been defined to be equivalent to ZeroOrMore(expr).

- Changed [...] to emit ZeroOrMore instead of OneOrMore.

- Removed code that treats ParserElements like iterables.

- Change all __diag__ switches to False.

Version 2.4.1.1 - July 24, 2019
-------------------------------
This is a re-release of version 2.4.1 to restore the release history
in PyPI, since the 2.4.1 release was deleted.

There are 3 known issues in this release, which are fixed in
the upcoming 2.4.2:

- API change adding support for `expr[...]` - the original
  code in 2.4.1 incorrectly implemented this as OneOrMore.
  Code using this feature under this relase should explicitly
  use `expr[0, ...]` for ZeroOrMore and `expr[1, ...]` for
  OneOrMore. In 2.4.2 you will be able to write `expr[...]`
  equivalent to `ZeroOrMore(expr)`.

- Bug if composing And, Or, MatchFirst, or Each expressions
  using an expression. This only affects code which uses
  explicit expression construction using the And, Or, etc.
  classes instead of using overloaded operators '+', '^', and
  so on. If constructing an And using a single expression,
  you may get an error that "cannot multiply ParserElement by
  0 or (0, 0)" or a Python `IndexError`. Change code like

cmd = Or(Word(alphas))

cmd = Or([Word(alphas)])

(Note that this is not the recommended style for constructing
  Or expressions.)

- Some newly-added `__diag__` switches are enabled by default,
  which may give rise to noisy user warnings for existing parsers.
  You can disable them using:

import pyparsing as pp
    pp.__diag__.warn_multiple_tokens_in_named_alternation = False
    pp.__diag__.warn_ungrouped_named_tokens_in_collection = False
    pp.__diag__.warn_name_set_on_empty_Forward = False
    pp.__diag__.warn_on_multiple_string_args_to_oneof = False
    pp.__diag__.enable_debug_on_named_expressions = False

In 2.4.2 these will all be set to False by default.

Version 2.4.1 - July, 2019
--------------------------
- NOTE: Deprecated functions and features that will be dropped
  in pyparsing 2.5.0 (planned next release):

. support for Python 2 - ongoing users running with
    Python 2 can continue to use pyparsing 2.4.1

. ParseResults.asXML() - if used for debugging, switch
    to using ParseResults.dump(); if used for data transfer,
    use ParseResults.asDict() to convert to a nested Python
    dict, which can then be converted to XML or JSON or
    other transfer format

. operatorPrecedence synonym for infixNotation -
    convert to calling infixNotation

. commaSeparatedList - convert to using
    pyparsing_common.comma_separated_list

. upcaseTokens and downcaseTokens - convert to using
    pyparsing_common.upcaseTokens and downcaseTokens

. __compat__.collect_all_And_tokens will not be settable to
    False to revert to pre-2.3.1 results name behavior -
    review use of names for MatchFirst and Or expressions
    containing And expressions, as they will return the
    complete list of parsed tokens, not just the first one.
    Use __diag__.warn_multiple_tokens_in_named_alternation
    (described below) to help identify those expressions
    in your parsers that will have changed as a result.

- A new shorthand notation has been added for repetition
  expressions: expr[min, max], with '...' valid as a min
  or max value:
     - expr[...] is equivalent to OneOrMore(expr)
     - expr[0, ...] is equivalent to ZeroOrMore(expr)
     - expr[1, ...] is equivalent to OneOrMore(expr)
     - expr[n, ...] or expr[n,] is equivalent
          to expr*n + ZeroOrMore(expr)
          (read as "n or more instances of expr")
     - expr[..., n] is equivalent to expr*(0, n)
     - expr[m, n] is equivalent to expr*(m, n)
  Note that expr[..., n] and expr[m, n] do not raise an exception
  if more than n exprs exist in the input stream.  If this
  behavior is desired, then write expr[..., n] + ~expr.

- '...' can also be used as short hand for SkipTo when used
  in adding parse expressions to compose an And expression.

Literal('start') + ... + Literal('end')
      And(['start', ..., 'end'])

are both equivalent to:

Literal('start') + SkipTo('end')("_skipped*") + Literal('end')

The '...' form has the added benefit of not requiring repeating
  the skip target expression. Note that the skipped text is
  returned with '_skipped' as a results name, and that the contents of
  `_skipped` will contain a list of text from all `...`s in the expression.

- '...' can also be used as a "skip forward in case of error" expression:

expr = "start" + (Word(nums).setName("int") | ...) + "end"

expr.parseString("start 456 end")
        ['start', '456', 'end']

expr.parseString("start 456 foo 789 end")
        ['start', '456', 'foo 789 ', 'end']
        - _skipped: ['foo 789 ']

expr.parseString("start foo end")
        ['start', 'foo ', 'end']
        - _skipped: ['foo ']

expr.parseString("start end")
        ['start', '', 'end']
        - _skipped: ['missing <int>']

Note that in all the error cases, the '_skipped' results name is
  present, showing a list of the extra or missing items.

This form is only valid when used with the '|' operator.

- Improved exception messages to show what was actually found, not
  just what was expected.

word = pp.Word(pp.alphas)
    pp.OneOrMore(word).parseString("aaa bbb 123", parseAll=True)

Former exception message:

pyparsing.ParseException: Expected end of text (at char 8), (line:1, col:9)

New exception message:

pyparsing.ParseException: Expected end of text, found '1' (at char 8), (line:1, col:9)

- Added diagnostic switches to help detect and warn about common
  parser construction mistakes, or enable additional parse
  debugging. Switches are attached to the pyparsing.__diag__
  namespace object:
     - warn_multiple_tokens_in_named_alternation - flag to enable warnings when a results
       name is defined on a MatchFirst or Or expression with one or more And subexpressions
       (default=True)
     - warn_ungrouped_named_tokens_in_collection - flag to enable warnings when a results
       name is defined on a containing expression with ungrouped subexpressions that also
       have results names (default=True)
     - warn_name_set_on_empty_Forward - flag to enable warnings whan a Forward is defined
       with a results name, but has no contents defined (default=False)
     - warn_on_multiple_string_args_to_oneof - flag to enable warnings whan oneOf is
       incorrectly called with multiple str arguments (default=True)
     - enable_debug_on_named_expressions - flag to auto-enable debug on all subsequent
       calls to ParserElement.setName() (default=False)

warn_multiple_tokens_in_named_alternation is intended to help
  those who currently have set __compat__.collect_all_And_tokens to
  False as a workaround for using the pre-2.3.1 code with named
  MatchFirst or Or expressions containing an And expression.

- Added ParseResults.from_dict classmethod, to simplify creation
  of a ParseResults with results names using a dict, which may be nested.
  This makes it easy to add a sub-level of named items to the parsed
  tokens in a parse action.

- Added asKeyword argument (default=False) to oneOf, to force
  keyword-style matching on the generated expressions.

- ParserElement.runTests now accepts an optional 'file' argument to
  redirect test output to a file-like object (such as a StringIO,
  or opened file). Default is to write to sys.stdout.

- conditionAsParseAction is a helper method for constructing a
  parse action method from a predicate function that simply
  returns a boolean result. Useful for those places where a
  predicate cannot be added using addCondition, but must be
  converted to a parse action (such as in infixNotation). May be
  used as a decorator if default message and exception types
  can be used. See ParserElement.addCondition for more details
  about the expected signature and behavior for predicate condition
  methods.

- While investigating issue #93, I found that Or and
  addCondition could interact to select an alternative that
  is not the longest match. This is because Or first checks
  all alternatives for matches without running attached
  parse actions or conditions, orders by longest match, and
  then rechecks for matches with conditions and parse actions.
  Some expressions, when checking with conditions, may end
  up matching on a shorter token list than originally matched,
  but would be selected because of its original priority.
  This matching code has been expanded to do more extensive
  searching for matches when a second-pass check matches a
  smaller list than in the first pass.

- Fixed issue #87, a regression in indented block.
  Reported by Renz Bagaporo, who submitted a very nice repro
  example, which makes the bug-fixing process a lot easier,
  thanks!

- Fixed MemoryError issue #85 and #91 with str generation for
  Forwards. Thanks decalage2 and Harmon758 for your patience.

- Modified setParseAction to accept None as an argument,
  indicating that all previously-defined parse actions for the
  expression should be cleared.

- Modified pyparsing_common.real and sci_real to parse reals
  without leading integer digits before the decimal point,
  consistent with Python real number formats. Original PR #98
  submitted by ansobolev.

- Modified runTests to call postParse function before dumping out
  the parsed results - allows for postParse to add further results,
  such as indications of additional validation success/failure.

- Updated statemachine example: refactored state transitions to use
  overridden classmethods; added <statename>Mixin class to simplify
  definition of application classes that "own" the state object and
  delegate to it to model state-specific properties and behavior.

- Added example nested_markup.py, showing a simple wiki markup with
  nested markup directives, and illustrating the use of '...' for
  skipping over input to match the next expression. (This example
  uses syntax that is not valid under Python 2.)

- Rewrote delta_time.py example (renamed from deltaTime.py) to
  fix some omitted formats and upgrade to latest pyparsing idioms,
  beginning with writing an actual BNF.

- With the help and encouragement from several contributors, including
  Matěj Cepl and Cengiz Kaygusuz, I've started cleaning up the internal
  coding styles in core pyparsing, bringing it up to modern coding
  practices from pyparsing's early development days dating back to
  2003. Whitespace has been largely standardized along PEP8 guidelines,
  removing extra spaces around parentheses, and adding them around
  arithmetic operators and after colons and commas. I was going to hold
  off on doing this work until after 2.4.1, but after cleaning up a
  few trial classes, the difference was so significant that I continued
  on to the rest of the core code base. This should facilitate future
  work and submitted PRs, allowing them to focus on substantive code
  changes, and not get sidetracked by whitespace issues.

Version 2.4.0 - April, 2019
---------------------------
- Well, it looks like the API change that was introduced in 2.3.1 was more
  drastic than expected, so for a friendlier forward upgrade path, this
  release:
  . Bumps the current version number to 2.4.0, to reflect this
    incompatible change.
  . Adds a pyparsing.__compat__ object for specifying compatibility with
    future breaking changes.
  . Conditionalizes the API-breaking behavior, based on the value
    pyparsing.__compat__.collect_all_And_tokens.  By default, this value
    will be set to True, reflecting the new bugfixed behavior. To set this
    value to False, add to your code:

import pyparsing
        pyparsing.__compat__.collect_all_And_tokens = False

. User code that is dependent on the pre-bugfix behavior can restore
    it by setting this value to False.

In 2.5 and later versions, the conditional code will be removed and
  setting the flag to True or False in these later versions will have no
  effect.

- Updated unitTests.py and simple_unit_tests.py to be compatible with
  "python setup.py test". To run tests using setup, do:

python setup.py test
      python setup.py test -s unitTests.suite
      python setup.py test -s simple_unit_tests.suite

Prompted by issue #83 and PR submitted by bdragon28, thanks.

- Fixed bug in runTests handling '\n' literals in quoted strings.

- Added tag_body attribute to the start tag expressions generated by
  makeHTMLTags, so that you can avoid using SkipTo to roll your own
  tag body expression:

a, aEnd = pp.makeHTMLTags('a')
      link = a + a.tag_body("displayed_text") + aEnd
      for t in s.searchString(html_page):
          print(t.displayed_text, '->', t.startA.href)

- indentedBlock failure handling was improved; PR submitted by TMiguelT,
  thanks!

- Address Py2 incompatibility in simpleUnitTests, plus explain() and
  Forward str() cleanup; PRs graciously provided by eswald.

- Fixed docstring with embedded '\w', which creates SyntaxWarnings in
  Py3.8, issue #80.

- Examples:

- Added example parser for rosettacode.org tutorial compiler.

- Added example to show how an HTML table can be parsed into a
    collection of Python lists or dicts, one per row.

- Updated SimpleSQL.py example to handle nested selects, reworked
    'where' expression to use infixNotation.

- Added include_preprocessor.py, similar to macroExpander.py.

- Examples using makeHTMLTags use new tag_body expression when
    retrieving a tag's body text.

- Updated examples that are runnable as unit tests:

python setup.py test -s examples.antlr_grammar_tests
        python setup.py test -s examples.test_bibparse

Version 2.3.1 - January, 2019
-----------------------------
- POSSIBLE API CHANGE: this release fixes a bug when results names were
  attached to a MatchFirst or Or object containing an And object.
  Previously, a results name on an And object within an enclosing MatchFirst
  or Or could return just the first token in the And. Now, all the tokens
  matched by the And are correctly returned. This may result in subtle
  changes in the tokens returned if you have this condition in your pyparsing
  scripts.

- New staticmethod ParseException.explain() to help diagnose parse exceptions
  by showing the failing input line and the trace of ParserElements in
  the parser leading up to the exception. explain() returns a multiline
  string listing each element by name. (This is still an experimental
  method, and the method signature and format of the returned string may
  evolve over the next few releases.)

Example:
        # define a parser to parse an integer followed by an
        # alphabetic word
        expr = pp.Word(pp.nums).setName("int")
               + pp.Word(pp.alphas).setName("word")
        try:
            # parse a string with a numeric second value instead of alpha
            expr.parseString("123 355")
        except pp.ParseException as pe:
            print(pp.ParseException.explain(pe))

Prints:
        123 355
            ^
        ParseException: Expected word (at char 4), (line:1, col:5)
        __main__.ExplainExceptionTest
        pyparsing.And - {int word}
        pyparsing.Word - word

explain() will accept any exception type and will list the function
  names and parse expressions in the stack trace. This is especially
  useful when an exception is raised in a parse action.

Note: explain() is only supported under Python 3.

- Fix bug in dictOf which could match an empty sequence, making it
  infinitely loop if wrapped in a OneOrMore.

- Added unicode sets to pyparsing_unicode for Latin-A and Latin-B ranges.

- Added ability to define custom unicode sets as combinations of other sets
  using multiple inheritance.

class Turkish_set(pp.pyparsing_unicode.Latin1, pp.pyparsing_unicode.LatinA):
        pass

turkish_word = pp.Word(Turkish_set.alphas)

- Updated state machine import examples, with state machine demos for:
  . traffic light
  . library book checkin/checkout
  . document review/approval

In the traffic light example, you can use the custom 'statemachine' keyword
  to define the states for a traffic light, and have the state classes
  auto-generated for you:

statemachine TrafficLightState:
          Red -> Green
          Green -> Yellow
          Yellow -> Red

Similar for state machines with named transitions, like the library book
  state example:

statemachine LibraryBookState:
          New -(shelve)-> Available
          Available -(reserve)-> OnHold
          OnHold -(release)-> Available
          Available -(checkout)-> CheckedOut
          CheckedOut -(checkin)-> Available

Once the classes are defined, then additional Python code can reference those
  classes to add class attributes, instance methods, etc.

See the examples in examples/statemachine

- Added an example parser for the decaf language. This language is used in
  CS compiler classes in many colleges and universities.

- Fixup of docstrings to Sphinx format, inclusion of test files in the source
  package, and convert markdown to rst throughout the distribution, great job
  by Matěj Cepl!

- Expanded the whitespace characters recognized by the White class to include
  all unicode defined spaces. Suggested in Issue #51 by rtkjbillo.

- Added optional postParse argument to ParserElement.runTests() to add a
  custom callback to be called for test strings that parse successfully. Useful
  for running tests that do additional validation or processing on the parsed
  results. See updated chemicalFormulas.py example.

- Removed distutils fallback in setup.py. If installing the package fails,
  please update to the latest version of setuptools. Plus overall project code
  cleanup (CRLFs, whitespace, imports, etc.), thanks Jon Dufresne!

- Fix bug in CaselessKeyword, to make its behavior consistent with
  Keyword(caseless=True). Fixes Issue #65 reported by telesphore.

Version 2.3.0 - October, 2018
-----------------------------
- NEW SUPPORT FOR UNICODE CHARACTER RANGES
  This release introduces the pyparsing_unicode namespace class, defining
  a series of language character sets to simplify the definition of alphas,
  nums, alphanums, and printables in the following language sets:
   . Arabic
   . Chinese
   . Cyrillic
   . Devanagari
   . Greek
   . Hebrew
   . Japanese (including Kanji, Katakana, and Hirigana subsets)
   . Korean
   . Latin1 (includes 7 and 8-bit Latin characters)
   . Thai
   . CJK (combination of Chinese, Japanese, and Korean sets)

For example, your code can define words using:

korean_word = Word(pyparsing_unicode.Korean.alphas)

See their use in the updated examples greetingInGreek.py and
  greetingInKorean.py.

This namespace class also offers access to these sets using their
  unicode identifiers.

- POSSIBLE API CHANGE: Fixed bug where a parse action that explicitly
  returned the input ParseResults could add another nesting level in
  the results if the current expression had a results name.

vals = pp.OneOrMore(pp.pyparsing_common.integer)("int_values")

def add_total(tokens):
            tokens['total'] = sum(tokens)
            return tokens  # this line can be removed

vals.addParseAction(add_total)
        print(vals.parseString("244 23 13 2343").dump())

Before the fix, this code would print (note the extra nesting level):

[244, 23, 13, 2343]
    - int_values: [244, 23, 13, 2343]
      - int_values: [244, 23, 13, 2343]
      - total: 2623
    - total: 2623

With the fix, this code now prints:

[244, 23, 13, 2343]
    - int_values: [244, 23, 13, 2343]
    - total: 2623

This fix will change the structure of ParseResults returned if a
  program defines a parse action that returns the tokens that were
  sent in. This is not necessary, and statements like "return tokens"
  in the example above can be safely deleted prior to upgrading to
  this release, in order to avoid the bug and get the new behavior.

Reported by seron in Issue #22, nice catch!

- POSSIBLE API CHANGE: Fixed a related bug where a results name
  erroneously created a second level of hierarchy in the returned
  ParseResults. The intent for accumulating results names into ParseResults
  is that, in the absence of Group'ing, all names get merged into a
  common namespace. This allows us to write:

key_value_expr = (Word(alphas)("key") + '=' + Word(nums)("value"))
       result = key_value_expr.parseString("a = 100")

and have result structured as {"key": "a", "value": "100"}
  instead of [{"key": "a"}, {"value": "100"}].

However, if a named expression is used in a higher-level non-Group
  expression that *also* has a name, a false sub-level would be created
  in the namespace:

num = pp.Word(pp.nums)
        num_pair = ("[" + (num("A") + num("B"))("values") + "]")
        U = num_pair.parseString("[ 10 20 ]")
        print(U.dump())

Since there is no grouping, "A", "B", and "values" should all appear
  at the same level in the results, as:

['[', '10', '20', ']']
        - A: '10'
        - B: '20'
        - values: ['10', '20']

Instead, an extra level of "A" and "B" show up under "values":

['[', '10', '20', ']']
        - A: '10'
        - B: '20'
        - values: ['10', '20']
          - A: '10'
          - B: '20'

This bug has been fixed. Now, if this hierarchy is desired, then a
  Group should be added:

num_pair = ("[" + pp.Group(num("A") + num("B"))("values") + "]")

Giving:

['[', ['10', '20'], ']']
        - values: ['10', '20']
          - A: '10'
          - B: '20'

But in no case should "A" and "B" appear in multiple levels. This bug-fix
  fixes that.

If you have current code which relies on this behavior, then add or remove
  Groups as necessary to get your intended results structure.

Reported by Athanasios Anastasiou.

- IndexError's raised in parse actions will get explicitly reraised
  as ParseExceptions that wrap the original IndexError. Since
  IndexError sometimes occurs as part of pyparsing's normal parsing
  logic, IndexErrors that are raised during a parse action may have
  gotten silently reinterpreted as parsing errors. To retain the
  information from the IndexError, these exceptions will now be
  raised as ParseExceptions that reference the original IndexError.
  This wrapping will only be visible when run under Python3, since it
  emulates "raise ... from ..." syntax.

Addresses Issue #4, reported by guswns0528.

- Added Char class to simplify defining expressions of a single
  character. (Char("abc") is equivalent to Word("abc", exact=1))

- Added class PrecededBy to perform lookbehind tests. PrecededBy is
  used in the same way as FollowedBy, passing in an expression that
  must occur just prior to the current parse location.

For fixed-length expressions like a Literal, Keyword, Char, or a
  Word with an `exact` or `maxLen` length given, `PrecededBy(expr)`
  is sufficient. For varying length expressions like a Word with no
  given maximum length, `PrecededBy` must be constructed with an
  integer `retreat` argument, as in
  `PrecededBy(Word(alphas, nums), retreat=10)`, to specify the maximum
  number of characters pyparsing must look backward to make a match.
  pyparsing will check all the values from 1 up to retreat characters
  back from the current parse location.

When stepping backwards through the input string, PrecededBy does
  *not* skip over whitespace.

PrecededBy can be created with a results name so that, even though
  it always returns an empty parse result, the result *can* include
  named results.

Idea first suggested in Issue #30 by Freakwill.

- Updated FollowedBy to accept expressions that contain named results,
  so that results names defined in the lookahead expression will be
  returned, even though FollowedBy always returns an empty list.
  Inspired by the same feature implemented in PrecededBy.

Version 2.2.2 - September, 2018
-------------------------------
- Fixed bug in SkipTo, if a SkipTo expression that was skipping to
  an expression that returned a list (such as an And), and the
  SkipTo was saved as a named result, the named result could be
  saved as a ParseResults - should always be saved as a string.
  Issue #28, reported by seron.

- Added simple_unit_tests.py, as a collection of easy-to-follow unit
  tests for various classes and features of the pyparsing library.
  Primary intent is more to be instructional than actually rigorous
  testing. Complex tests can still be added in the unitTests.py file.

- New features added to the Regex class:
  - optional asGroupList parameter, returns all the capture groups as
    a list
  - optional asMatch parameter, returns the raw re.match result
  - new sub(repl) method, which adds a parse action calling
    re.sub(pattern, repl, parsed_result). Simplifies creating
    Regex expressions to be used with transformString. Like re.sub,
    repl may be an ordinary string (similar to using pyparsing's
    replaceWith), or may contain references to capture groups by group
    number, or may be a callable that takes an re match group and
    returns a string.

For instance:
        expr = pp.Regex(r"([Hh]\d):\s*(.*)").sub(r"<\1>\2</\1>")
        expr.transformString("h1: This is the title")

will return
        <h1>This is the title</h1>

- Fixed omission of LICENSE file in source tarball, also added
  CODE_OF_CONDUCT.md per GitHub community standards.

Version 2.2.1 - September, 2018
-------------------------------
- Applied changes necessary to migrate hosting of pyparsing source
  over to GitHub. Many thanks for help and contributions from hugovk,
  jdufresne, and cngkaygusuz among others through this transition,
  sorry it took me so long!

- Fixed import of collections.abc to address DeprecationWarnings
  in Python 3.7.

- Updated oc.py example to support function calls in arithmetic
  expressions; fixed regex for '==' operator; and added packrat
  parsing. Raised on the pyparsing wiki by Boris Marin, thanks!

- Fixed bug in select_parser.py example, group_by_terms was not
  reported. Reported on SF bugs by Adam Groszer, thanks Adam!

- Added "Getting Started" section to the module docstring, to
  guide new users to the most common starting points in pyparsing's
  API.

- Fixed bug in Literal and Keyword classes, which erroneously
  raised IndexError instead of ParseException.

Version 2.2.0 - March, 2017
---------------------------
- Bumped minor version number to reflect compatibility issues with
  OneOrMore and ZeroOrMore bugfixes in 2.1.10. (2.1.10 fixed a bug
  that was introduced in 2.1.4, but the fix could break code
  written against 2.1.4 - 2.1.9.)

- Updated setup.py to address recursive import problems now
  that pyparsing is part of 'packaging' (used by setuptools).
  Patch submitted by Joshua Root, much thanks!

- Fixed KeyError issue reported by Yann Bizeul when using packrat
  parsing in the Graphite time series database, thanks Yann!

- Fixed incorrect usages of '\' in literals, as described in
  https://docs.python.org/3/whatsnew/3.6.html#deprecated-python-behavior
  Patch submitted by Ville Skyttä - thanks!

- Minor internal change when using '-' operator, to be compatible
  with ParserElement.streamline() method.

- Expanded infixNotation to accept a list or tuple of parse actions
  to attach to an operation.

- New unit test added for dill support for storing pyparsing parsers.
  Ordinary Python pickle can be used to pickle pyparsing parsers as
  long as they do not use any parse actions. The 'dill' module is an
  extension to pickle which *does* support pickling of attached
  parse actions.

Version 2.1.10 - October, 2016
-------------------------------
- Fixed bug in reporting named parse results for ZeroOrMore
  expressions, thanks Ethan Nash for reporting this!

- Fixed behavior of LineStart to be much more predictable.
  LineStart can now be used to detect if the next parse position
  is col 1, factoring in potential leading whitespace (which would
  cause LineStart to fail). Also fixed a bug in col, which is
  used in LineStart, where '\n's were erroneously considered to
  be column 1.

- Added support for multiline test strings in runTests.

- Fixed bug in ParseResults.dump when keys were not strings.
  Also changed display of string values to show them in quotes,
  to help distinguish parsed numeric strings from parsed integers
  that have been converted to Python ints.

Version 2.1.9 - September, 2016
-------------------------------
- Added class CloseMatch, a variation on Literal which matches
  "close" matches, that is, strings with at most 'n' mismatching
  characters.

- Fixed bug in Keyword.setDefaultKeywordChars(), reported by Kobayashi
  Shinji - nice catch, thanks!

- Minor API change in pyparsing_common. Renamed some of the common
  expressions to PEP8 format (to be consistent with the other
  pyparsing_common expressions):
  . signedInteger -> signed_integer
  . sciReal -> sci_real

Also, in trying to stem the API bloat of pyparsing, I've copied
  some of the global expressions and helper parse actions into
  pyparsing_common, with the originals to be deprecated and removed
  in a future release:
  . commaSeparatedList -> pyparsing_common.comma_separated_list
  . upcaseTokens -> pyparsing_common.upcaseTokens
  . downcaseTokens -> pyparsing_common.downcaseTokens

(I don't expect any other expressions, like the comment expressions,
  quotedString, or the Word-helping strings like alphas, nums, etc.
  to migrate to pyparsing_common - they are just too pervasive. As for
  the PEP8 vs camelCase naming, all the expressions are PEP8, while
  the parse actions in pyparsing_common are still camelCase. It's a
  small step - when pyparsing 3.0 comes around, everything will change
  to PEP8 snake case.)

- Fixed Python3 compatibility bug when using dict keys() and values()
  in ParseResults.getName().

- After some prodding, I've reworked the unitTests.py file for
  pyparsing over the past few releases. It uses some variations on
  unittest to handle my testing style. The test now:
  . auto-discovers its test classes (while maintining their order
    of definition)
  . suppresses voluminous 'print' output for tests that pass

Version 2.1.8 - August, 2016
----------------------------
- Fixed issue in the optimization to _trim_arity, when the full
  stacktrace is retrieved to determine if a TypeError is raised in
  pyparsing or in the caller's parse action. Code was traversing
  the full stacktrace, and potentially encountering UnicodeDecodeError.

- Fixed bug in ParserElement.inlineLiteralsUsing, causing infinite
  loop with Suppress.

- Fixed bug in Each, when merging named results from multiple
  expressions in a ZeroOrMore or OneOrMore. Also fixed bug when
  ZeroOrMore expressions were erroneously treated as required
  expressions in an Each expression.

- Added a few more inline doc examples.

- Improved use of runTests in several example scripts.

Version 2.1.7 - August, 2016
----------------------------
- Fixed regression reported by Andrea Censi (surfaced in PyContracts
  tests) when using ParseSyntaxExceptions (raised when using operator '-')
  with packrat parsing.

- Minor fix to oneOf, to accept all iterables, not just space-delimited
  strings and lists. (If you have a list or set of strings, it is
  not necessary to concat them using ' '.join to pass them to oneOf,
  oneOf will accept the list or set or generator directly.)

Version 2.1.6 - August, 2016
----------------------------
- *Major packrat upgrade*, inspired by patch provided by Tal Einat -
  many, many, thanks to Tal for working on this! Tal's tests show
  faster parsing performance (2X in some tests), *and* memory reduction
  from 3GB down to ~100MB! Requires no changes to existing code using
  packratting. (Uses OrderedDict, available in Python 2.7 and later.
  For Python 2.6 users, will attempt to import from ordereddict
  backport. If not present, will implement pure-Python Fifo dict.)

- Minor API change - to better distinguish between the flexible
  numeric types defined in pyparsing_common, I've changed "numeric"
  (which parsed numbers of different types and returned int for ints,
  float for floats, etc.) and "number" (which parsed numbers of int
  or float type, and returned all floats) to "number" and "fnumber"
  respectively. I hope the "f" prefix of "fnumber" will be a better
  indicator of its internal conversion of parsed values to floats,
  while the generic "number" is similar to the flexible number syntax
  in other languages. Also fixed a bug in pyparsing_common.numeric
  (now renamed to pyparsing_common.number), integers were parsed and
  returned as floats instead of being retained as ints.

- Fixed bug in upcaseTokens and downcaseTokens introduced in 2.1.5,
  when the parse action was used in conjunction with results names.
  Reported by Steven Arcangeli from the dql project, thanks for your
  patience, Steven!

- Major change to docs! After seeing some comments on reddit about
  general issue with docs of Python modules, and thinking that I'm a
  little overdue in doing some doc tuneup on pyparsing, I decided to
  following the suggestions of the redditor and add more inline examples
  to the pyparsing reference documentation. I hope this addition
  will clarify some of the more common questions people have, especially
  when first starting with pyparsing/Python.

- Deprecated ParseResults.asXML. I've never been too happy with this
  method, and it usually forces some unnatural code in the parsers in
  order to get decent tag names. The amount of guesswork that asXML
  has to do to try to match names with values should have been a red
  flag from day one. If you are using asXML, you will need to implement
  your own ParseResults->XML serialization. Or consider migrating to
  a more current format such as JSON (which is very easy to do:
  results_as_json = json.dumps(parse_result.asDict()) Hopefully, when
  I remove this code in a future version, I'll also be able to simplify
  some of the craziness in ParseResults, which IIRC was only there to try
  to make asXML work.

- Updated traceParseAction parse action decorator to show the repr
  of the input and output tokens, instead of the str format, since
  str has been simplified to just show the token list content.

(The change to ParseResults.__str__ occurred in pyparsing 2.0.4, but
  it seems that didn't make it into the release notes - sorry! Too
  many users, especially beginners, were confused by the
  "([token_list], {names_dict})" str format for ParseResults, thinking
  they were getting a tuple containing a list and a dict. The full form
  can be seen if using repr().)

For tracing tokens in and out of parse actions, the more complete
  repr form provides important information when debugging parse actions.

Verison 2.1.5 - June, 2016
------------------------------
- Added ParserElement.split() generator method, similar to re.split().
  Includes optional arguments maxsplit (to limit the number of splits),
  and includeSeparators (to include the separating matched text in the
  returned output, default=False).

- Added a new parse action construction helper tokenMap, which will
  apply a function and optional arguments to each element in a
  ParseResults. So this parse action:

def lowercase_all(tokens):
          return [str(t).lower() for t in tokens]
      OneOrMore(Word(alphas)).setParseAction(lowercase_all)

can now be written:

OneOrMore(Word(alphas)).setParseAction(tokenMap(str.lower))

Also simplifies writing conversion parse actions like:

integer = Word(nums).setParseAction(lambda t: int(t[0]))

to just:

integer = Word(nums).setParseAction(tokenMap(int))

If additional arguments are necessary, they can be included in the
  call to tokenMap, as in:

hex_integer = Word(hexnums).setParseAction(tokenMap(int, 16))

- Added more expressions to pyparsing_common:
  . IPv4 and IPv6 addresses (including long, short, and mixed forms
    of IPv6)
  . MAC address
  . ISO8601 date and date time strings (with named fields for year, month, etc.)
  . UUID (xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx)
  . hex integer (returned as int)
  . fraction (integer '/' integer, returned as float)
  . mixed integer (integer '-' fraction, or just fraction, returned as float)
  . stripHTMLTags (parse action to remove tags from HTML source)
  . parse action helpers convertToDate and convertToDatetime to do custom parse
    time conversions of parsed ISO8601 strings

- runTests now returns a two-tuple: success if all tests succeed,
  and an output list of each test and its output lines.

- Added failureTests argument (default=False) to runTests, so that
  tests can be run that are expected failures, and runTests' success
  value will return True only if all tests *fail* as expected. Also,
  parseAll now defaults to True.

- New example numerics.py, shows samples of parsing integer and real
  numbers using locale-dependent formats:

4.294.967.295,000
    4 294 967 295,000
    4,294,967,295.000

Version 2.1.4 - May, 2016
------------------------------
- Split out the '==' behavior in ParserElement, now implemented
  as the ParserElement.matches() method. Using '==' for string test
  purposes will be removed in a future release.

- Expanded capabilities of runTests(). Will now accept embedded
  comments (default is Python style, leading '#' character, but
  customizable). Comments will be emitted along with the tests and
  test output. Useful during test development, to create a test string
  consisting only of test case description comments separated by
  blank lines, and then fill in the test cases. Will also highlight
  ParseFatalExceptions with "(FATAL)".

- Added a 'pyparsing_common' class containing common/helpful little
  expressions such as integer, float, identifier, etc. I used this
  class as a sort of embedded namespace, to contain these helpers
  without further adding to pyparsing's namespace bloat.

- Minor enhancement to traceParseAction decorator, to retain the
  parse action's name for the trace output.

- Added optional 'fatal' keyword arg to addCondition, to indicate that
  a condition failure should halt parsing immediately.

Version 2.1.3 - May, 2016
------------------------------
- _trim_arity fix in 2.1.2 was very version-dependent on Py 3.5.0.
  Now works for Python 2.x, 3.3, 3.4, 3.5.0, and 3.5.1 (and hopefully
  beyond).

Version 2.1.2 - May, 2016
------------------------------
- Fixed bug in _trim_arity when pyparsing code is included in a
  PyInstaller, reported by maluwa.

- Fixed catastrophic regex backtracking in implementation of the
  quoted string expressions (dblQuotedString, sglQuotedString, and
  quotedString). Reported on the pyparsing wiki by webpentest,
  good catch! (Also tuned up some other expressions susceptible to the
  same backtracking problem, such as cStyleComment, cppStyleComment,
  etc.)

Version 2.1.1 - March, 2016
---------------------------
- Added support for assigning to ParseResults using slices.

- Fixed bug in ParseResults.toDict(), in which dict values were always
  converted to dicts, even if they were just unkeyed lists of tokens.
  Reported on SO by Gerald Thibault, thanks Gerald!

- Fixed bug in SkipTo when using failOn, reported by robyschek, thanks!

- Fixed bug in Each introduced in 2.1.0, reported by AND patch and
  unit test submitted by robyschek, well done!

- Removed use of functools.partial in replaceWith, as this creates
  an ambiguous signature for the generated parse action, which fails in
  PyPy. Reported by Evan Hubinger, thanks Evan!

- Added default behavior to QuotedString to convert embedded '\t', '\n',
  etc. characters to their whitespace counterparts. Found during Q&A
  exchange on SO with Maxim.

Version 2.1.0 - February, 2016
------------------------------
- Modified the internal _trim_arity method to distinguish between
  TypeError's raised while trying to determine parse action arity and
  those raised within the parse action itself. This will clear up those
  confusing "<lambda>() takes exactly 1 argument (0 given)" error
  messages when there is an actual TypeError in the body of the parse
  action. Thanks to all who have raised this issue in the past, and
  most recently to Michael Cohen, who sent in a proposed patch, and got
  me to finally tackle this problem.

- Added compatibility for pickle protocols 2-4 when pickling ParseResults.
  In Python 2.x, protocol 0 was the default, and protocol 2 did not work.
  In Python 3.x, protocol 3 is the default, so explicitly naming
  protocol 0 or 1 was required to pickle ParseResults. With this release,
  all protocols 0-4 are supported. Thanks for reporting this on StackOverflow,
  Arne Wolframm, and for providing a nice simple test case!

- Added optional 'stopOn' argument to ZeroOrMore and OneOrMore, to
  simplify breaking on stop tokens that would match the repetition
  expression.

It is a common problem to fail to look ahead when matching repetitive
  tokens if the sentinel at the end also matches the repetition
  expression, as when parsing "BEGIN aaa bbb ccc END" with:

"BEGIN" + OneOrMore(Word(alphas)) + "END"

Since "END" matches the repetition expression "Word(alphas)", it will
  never get parsed as the terminating sentinel. Up until now, this has
  to be resolved by the user inserting their own negative lookahead:

"BEGIN" + OneOrMore(~Literal("END") + Word(alphas)) + "END"

Using stopOn, they can more easily write:

"BEGIN" + OneOrMore(Word(alphas), stopOn="END") + "END"

The stopOn argument can be a literal string or a pyparsing expression.
  Inspired by a question by Lamakaha on StackOverflow (and many previous
  questions with the same negative-lookahead resolution).

- Added expression names for many internal and builtin expressions, to
  reduce name and error message overhead during parsing.

- Converted helper lambdas to functions to refactor and add docstring
  support.

- Fixed ParseResults.asDict() to correctly convert nested ParseResults
  values to dicts.

- Cleaned up some examples, fixed typo in fourFn.py identified by
  aristotle2600 on reddit.

- Removed keepOriginalText helper method, which was deprecated ages ago.
  Superceded by originalTextFor.

- Same for the Upcase class, which was long ago deprecated and replaced
  with the upcaseTokens method.

Version 2.0.7 - December, 2015
------------------------------
- Simplified string representation of Forward class, to avoid memory
  and performance errors while building ParseException messages. Thanks,
  Will McGugan, Andrea Censi, and Martijn Vermaat for the bug reports and
  test code.

- Cleaned up additional issues from enhancing the error messages for
  Or and MatchFirst, handling Unicode values in expressions. Fixes Unicode
  encoding issues in Python 2, thanks to Evan Hubinger for the bug report.

- Fixed implementation of dir() for ParseResults - was leaving out all the
  defined methods and just adding the custom results names.

- Fixed bug in ignore() that was introduced in pyparsing 1.5.3, that would
  not accept a string literal as the ignore expression.

- Added new example parseTabularData.py to illustrate parsing of data
  formatted in columns, with detection of empty cells.

- Updated a number of examples to more current Python and pyparsing
  forms.

Version 2.0.6 - November, 2015
------------------------------
- Fixed a bug in Each when multiple Optional elements are present.
  Thanks for reporting this, whereswalden on SO.

- Fixed another bug in Each, when Optional elements have results names
  or parse actions, reported by Max Rothman - thank you, Max!

- Added optional parseAll argument to runTests, whether tests should
  require the entire input string to be parsed or not (similar to
  parseAll argument to parseString). Plus a little neaten-up of the
  output on Python 2 (no stray ()'s).

- Modified exception messages from MatchFirst and Or expressions. These
  were formerly misleading as they would only give the first or longest
  exception mismatch error message. Now the error message includes all
  the alternatives that were possible matches. Originally proposed by
  a pyparsing user, but I've lost the email thread - finally figured out
  a fairly clean way to do this.

- Fixed a bug in Or, when a parse action on an alternative raises an
  exception, other potentially matching alternatives were not always tried.
  Reported by TheVeryOmni on the pyparsing wiki, thanks!

- Fixed a bug to dump() introduced in 2.0.4, where list values were shown
  in duplicate.

Version 2.0.5 - October, 2015
-----------------------------
- (&$(@#&$(@!!!!  Some "print" statements snuck into pyparsing v2.0.4,
  breaking Python 3 compatibility! Fixed. Reported by jenshn, thanks!

Version 2.0.4 - October, 2015
-----------------------------
- Added ParserElement.addCondition, to simplify adding parse actions
  that act primarily as filters. If the given condition evaluates False,
  pyparsing will raise a ParseException. The condition should be a method
  with the same method signature as a parse action, but should return a
  boolean. Suggested by Victor Porton, nice idea Victor, thanks!

- Slight mod to srange to accept unicode literals for the input string,
  such as "[а-яА-Я]" instead of "[\u0430-\u044f\u0410-\u042f]". Thanks
  to Alexandr Suchkov for the patch!

- Enhanced implementation of replaceWith.

- Fixed enhanced ParseResults.dump() method when the results consists
  only of an unnamed array of sub-structure results. Reported by Robin
  Siebler, thanks for your patience and persistence, Robin!

- Fixed bug in fourFn.py example code, where pi and e were defined using
  CaselessLiteral instead of CaselessKeyword. This was not a problem until
  adding a new function 'exp', and the leading 'e' of 'exp' was accidentally
  parsed as the mathematical constant 'e'. Nice catch, Tom Grydeland - thanks!

- Adopt new-fangled Python features, like decorators and ternary expressions,
  per suggestions from Williamzjc - thanks William! (Oh yeah, I'm not
  supporting Python 2.3 with this code any more...) Plus, some additional
  code fixes/cleanup - thanks again!

- Added ParserElement.runTests, a little test bench for quickly running
  an expression against a list of sample input strings. Basically, I got
  tired of writing the same test code over and over, and finally added it
  as a test point method on ParserElement.

- Added withClass helper method, a simplified version of withAttribute for
  the common but annoying case when defining a filter on a div's class -
  made difficult because 'class' is a Python reserved word.

Version 2.0.3 - October, 2014
-----------------------------
- Fixed escaping behavior in QuotedString. Formerly, only quotation
  marks (or characters designated as quotation marks in the QuotedString
  constructor) would be escaped. Now all escaped characters will be
  escaped, and the escaping backslashes will be removed.

- Fixed regression in ParseResults.pop() - pop() was pretty much
  broken after I added *improvements* in 2.0.2. Reported by Iain
  Shelvington, thanks Iain!

- Fixed bug in And class when initializing using a generator.

- Enhanced ParseResults.dump() method to list out nested ParseResults that
  are unnamed arrays of sub-structures.

- Fixed UnboundLocalError under Python 3.4 in oneOf method, reported
  on Sourceforge by aldanor, thanks!

- Fixed bug in ParseResults __init__ method, when returning non-ParseResults
  types from parse actions that implement __eq__. Raised during discussion
  on the pyparsing wiki with cyrfer.

Version 2.0.2 - April, 2014
---------------------------
- 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 addtional positional and
  keyword arguments (such as indent, width, etc.), which get passed
  through directly to the pprint method
  (see https://docs.python.org/2/library/pprint.html#pprint.pprint).

- 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
  dict.pop().

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

- Cleaned up my unit test environment, now runs with Python 2.6 and
  3.3.

Version 2.0.1 - July, 2013
--------------------------
- Removed use of "nonlocal" that prevented using this version of
  pyparsing with Python 2.6 and 2.7. This will make it easier to
  install for packages that depend on pyparsing, under Python
  versions 2.6 and later. Those using older versions of Python
  will have to manually install pyparsing 1.5.7.

- Fixed implementation of <<= operator to return self; reported by
  Luc J. Bourhis, with patch fix by Mathias Mamsch - thanks, Luc
  and Mathias!

Version 2.0.0 - November, 2012
------------------------------
- Rather than release another combined Python 2.x/3.x release
  I've decided to start a new major version that is only
  compatible with Python 3.x (and consequently Python 2.7 as
  well due to backporting of key features). This version will
  be the main development path from now on, with little follow-on
  development on the 1.5.x path.

- Operator '<<' is now deprecated, in favor of operator '<<=' for
  attaching parsing expressions to Forward() expressions. This is
  being done to address precedence of operations problems with '<<'.
  Operator '<<' will be removed in a future version of pyparsing.

Version 1.5.7 - November, 2012
-----------------------------
- NOTE: This is the last release of pyparsing that will try to
  maintain compatibility with Python versions < 2.6. The next
  release of pyparsing will be version 2.0.0, using new Python
  syntax that will not be compatible for Python version 2.5 or
  older.

- An awesome new example is included in this release, submitted
  by Luca DellOlio, for parsing ANTLR grammar definitions, nice
  work Luca!

- Fixed implementation of ParseResults.__str__ to use Pythonic
  ''.join() instead of repeated string concatenation. This
  purportedly has been a performance issue under PyPy.

- Fixed bug in ParseResults.__dir__ under Python 3, reported by
  Thomas Kluyver, thank you Thomas!

- Added ParserElement.inlineLiteralsUsing static method, to
  override pyparsing's default behavior of converting string
  literals to Literal instances, to use other classes (such
  as Suppress or CaselessLiteral).

- Added new operator '<<=', which will eventually replace '<<' for
  storing the contents of a Forward(). '<<=' does not have the same
  operator precedence problems that '<<' does.

- 'operatorPrecedence' is being renamed 'infixNotation' as a better
  description of what this helper function creates. 'operatorPrecedence'
  is deprecated, and will be dropped entirely in a future release.

- Added optional arguments lpar and rpar to operatorPrecedence, so that
  expressions that use it can override the default suppression of the
  grouping characters.

- Added support for using single argument builtin functions as parse
  actions.  Now you can write 'expr.setParseAction(len)' and get back
  the length of the list of matched tokens.  Supported builtins are:
  sum, len, sorted, reversed, list, tuple, set, any, all, min, and max.
  A script demonstrating this feature is included in the examples
  directory.

- Improved linking in generated docs, proposed on the pyparsing wiki
  by techtonik, thanks!

- Fixed a bug in the definition of 'alphas', which was based on the
  string.uppercase and string.lowercase "constants", which in fact
  *aren't* constant, but vary with locale settings. This could make
  parsers locale-sensitive in a subtle way. Thanks to Kef Schecter for
  his diligence in following through on reporting and monitoring
  this bugfix!

- Fixed a bug in the Py3 version of pyparsing, during exception
  handling with packrat parsing enabled, reported by Catherine
  Devlin - thanks Catherine!

- Fixed typo in ParseBaseException.__dir__, reported anonymously on
  the SourceForge bug tracker, thank you Pyparsing User With No Name.

- Fixed bug in srange when using '\x###' hex character codes.

- Addeed optional 'intExpr' argument to countedArray, so that you
  can define your own expression that will evaluate to an integer,
  to be used as the count for the following elements. Allows you
  to define a countedArray with the count given in hex, for example,
  by defining intExpr as "Word(hexnums).setParseAction(int(t[0],16))".

Version 1.5.6 - June, 2011
----------------------------
- Cleanup of parse action normalizing code, to be more version-tolerant,
  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 find
  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 defining
  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 overlapping
  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 expr.setResultsName('name',listAllMatches=True).

- Fixed up internal list flattener to use iteration instead of recursion,
  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 test_bibparse.py (thanks, Matthew!)
  . groupUsingListAllMatches.py - demo using trailing '*' for results
    names

Version 1.5.5 - August, 2010
----------------------------

- Typo in Python3 version of pyparsing, "builtin" should be "builtins".
  (sigh)

Version 1.5.4 - August, 2010
----------------------------

- Fixed __builtins__ and file references in Python 3 code, thanks to
  Greg Watson, saulspatz, sminos, and Mark Summerfield for reporting
  their Python 3 experiences.

- Added new example, apicheck.py, as a sample of scanning a Tcl-like
  language for functions with incorrect number of arguments (difficult
  to track down in Tcl languages).  This example uses some interesting
  methods for capturing exceptions while scanning through source
  code.

- Added new example deltaTime.py, that takes everyday time references
  like "an hour from now", "2 days ago", "next Sunday at 2pm".

Version 1.5.3 - June, 2010
--------------------------

- ======= NOTE:  API CHANGE!!!!!!! ===============
  With this release, and henceforward, the pyparsing module is
  imported as "pyparsing" on both Python 2.x and Python 3.x versions.

- Fixed up setup.py to auto-detect Python version and install the
  correct version of pyparsing - suggested by Alex Martelli,
  thanks, Alex! (and my apologies to all those who struggled with
  those spurious installation errors caused by my earlier
  fumblings!)

- Fixed bug on Python3 when using parseFile, getting bytes instead of
  a str from the input file.

- Fixed subtle bug in originalTextFor, if followed by
  significant whitespace (like a newline) - discovered by
  Francis Vidal, thanks!

- Fixed very sneaky bug in Each, in which Optional elements were
  not completely recognized as optional - found by Tal Weiss, thanks
  for your patience.

- Fixed off-by-1 bug in line() method when the first line of the
  input text was an empty line. Thanks to John Krukoff for submitting
  a patch!

- Fixed bug in transformString if grammar contains Group expressions,
  thanks to patch submitted by barnabas79, nice work!

- Fixed bug in originalTextFor in which trailing comments or otherwised
  ignored text got slurped in with the matched expression.  Thanks to
  michael_ramirez44 on the pyparsing wiki for reporting this just in
  time to get into this release!

- Added better support for summing ParseResults, see the new example,
  parseResultsSumExample.py.

- Added support for composing a Regex using a compiled RE object;
  thanks to my new colleague, Mike Thornton!

- In version 1.5.2, I changed the way exceptions are raised in order
  to simplify the stacktraces reported during parsing.  An anonymous
  user posted a bug report on SF that this behavior makes it difficult
  to debug some complex parsers, or parsers nested within parsers. In
  this release I've added a class attribute ParserElement.verbose_stacktrace,
  with a default value of False. If you set this to True, pyparsing will
  report stacktraces using the pre-1.5.2 behavior.

- New examples:

. pymicko.py, a MicroC compiler submitted by Zarko Zivanov.
    (Note: this example is separately licensed under the GPLv3,
    and requires Python 2.6 or higher.)  Thank you, Zarko!

. oc.py, a subset C parser, using the BNF from the 1996 Obfuscated C
    Contest.

. stateMachine2.py, a modified version of stateMachine.py submitted
    by Matt Anderson, that is compatible with Python versions 2.7 and
    above - thanks so much, Matt!

. select_parser.py, a parser for reading SQLite SELECT statements,
    as specified at https://www.sqlite.org/lang_select.html this goes
    into much more detail than the simple SQL parser included in pyparsing's
    source code

. excelExpr.py, a *simplistic* first-cut at a parser for Excel
    expressions, which I originally posted on comp.lang.python in January,
    2010; beware, this parser omits many common Excel cases (addition of
    numbers represented as strings, references to named ranges)

. cpp_enum_parser.py, a nice little parser posted my Mark Tolonen on
    comp.lang.python in August, 2009 (redistributed here with Mark's
    permission).  Thanks a bunch, Mark!

. partial_gene_match.py, a sample I posted to Stackoverflow.com,
    implementing a special variation on Literal that does "close" matching,
    up to a given number of allowed mismatches.  The application was to
    find matching gene sequences, with allowance for one or two mismatches.

. tagCapture.py, a sample showing how to use a Forward placeholder to
    enforce matching of text parsed in a previous expression.

. matchPreviousDemo.py, simple demo showing how the matchPreviousLiteral
    helper method is used to match a previously parsed token.

Version 1.5.2 - April, 2009
------------------------------
- Added pyparsing_py3.py module, so that Python 3 users can use
  pyparsing by changing their pyparsing import statement to:

import pyparsing_py3

Thanks for help from Patrick Laban and his friend Geremy
  Condra on the pyparsing wiki.

- Removed __slots__ declaration on ParseBaseException, for
  compatibility with IronPython 2.0.1.  Raised by David
  Lawler on the pyparsing wiki, thanks David!

- Fixed bug in SkipTo/failOn handling - caught by eagle eye
  cpennington on the pyparsing wiki!

- Fixed second bug in SkipTo when using the ignore constructor
  argument, reported by Catherine Devlin, thanks!

- Fixed obscure bug reported by Eike Welk when using a class
  as a ParseAction with an errant __getitem__ method.

- Simplified exception stack traces when reporting parse
  exceptions back to caller of parseString or parseFile - thanks
  to a tip from Peter Otten on comp.lang.python.

- Changed behavior of scanString to avoid infinitely looping on
  expressions that match zero-length strings.  Prompted by a
  question posted by ellisonbg on the wiki.

- Enhanced classes that take a list of expressions (And, Or,
  MatchFirst, and Each) to accept generator expressions also.
  This can be useful when generating lists of alternative
  expressions, as in this case, where the user wanted to match
  any repetitions of '+', '*', '#', or '.', but not mixtures
  of them (that is, match '+++', but not '+-+'):

codes = "+*#."
      format = MatchFirst(Word(c) for c in codes)

Based on a problem posed by Denis Spir on the Python tutor
  list.

- Added new example eval_arith.py, which extends the example
  simpleArith.py to actually evaluate the parsed expressions.

Version 1.5.1 - October, 2008
-------------------------------
- Added new helper method originalTextFor, to replace the use of
  the current keepOriginalText parse action.  Now instead of
  using the parse action, as in:

fullName = Word(alphas) + Word(alphas)
      fullName.setParseAction(keepOriginalText)

(in this example, we used keepOriginalText to restore any white
  space that may have been skipped between the first and last
  names)
  You can now write:

fullName = originalTextFor(Word(alphas) + Word(alphas))

The implementation of originalTextFor is simpler and faster than
  keepOriginalText, and does not depend on using the inspect or
  imp modules.

- Added optional parseAll argument to parseFile, to be consistent
  with parseAll argument to parseString.  Posted by pboucher on the
  pyparsing wiki, thanks!

- Added failOn argument to SkipTo, so that grammars can define
  literal strings or pyparsing expressions which, if found in the
  skipped text, will cause SkipTo to fail.  Useful to prevent
  SkipTo from reading past terminating expression.  Instigated by
  question posed by Aki Niimura on the pyparsing wiki.

- Fixed bug in nestedExpr if multi-character expressions are given
  for nesting delimiters.  Patch provided by new pyparsing user,
  Hans-Martin Gaudecker - thanks, H-M!

- Removed dependency on xml.sax.saxutils.escape, and included
  internal implementation instead - proposed by Mike Droettboom on
  the pyparsing mailing list, thanks Mike!  Also fixed erroneous
  mapping in replaceHTMLEntity of &quot; to ', now correctly maps
  to ".  (Also added support for mapping &apos; to '.)

- Fixed typo in ParseResults.insert, found by Alejandro Dubrovsky,
  good catch!

- Added __dir__() methods to ParseBaseException and ParseResults,
  to support new dir() behavior in Py2.6 and Py3.0.  If dir() is
  called on a ParseResults object, the returned list will include
  the base set of attribute names, plus any results names that are
  defined.

- Fixed bug in ParseResults.asXML(), in which the first named
  item within a ParseResults gets reported with an <ITEM> tag
  instead of with the correct results name.

- Fixed bug in '-' error stop, when '-' operator is used inside a
  Combine expression.

- Reverted generator expression to use list comprehension, for
  better compatibility with old versions of Python.  Reported by
  jester/artixdesign on the SourceForge pyparsing discussion list.

- Fixed bug in parseString(parseAll=True), when the input string
  ends with a comment or whitespace.

- Fixed bug in LineStart and LineEnd that did not recognize any
  special whitespace chars defined using ParserElement.setDefault-
  WhitespaceChars, found while debugging an issue for Marek Kubica,
  thanks for the new test case, Marek!

- Made Forward class more tolerant of subclassing.

Version 1.5.0 - June, 2008
--------------------------
This version of pyparsing includes work on two long-standing
FAQ's: support for forcing parsing of the complete input string
(without having to explicitly append StringEnd() to the grammar),
and a method to improve the mechanism of detecting where syntax
errors occur in an input string with various optional and
alternative paths.  This release also includes a helper method
to simplify definition of indentation-based grammars.  With
these changes (and the past few minor updates), I thought it was
finally time to bump the minor rev number on pyparsing - so
1.5.0 is now available!  Read on...

- AT LAST!!!  You can now call parseString and have it raise
  an exception if the expression does not parse the entire
  input string.  This has been an FAQ for a LONG time.

The parseString method now includes an optional parseAll
  argument (default=False).  If parseAll is set to True, then
  the given parse expression must parse the entire input
  string.  (This is equivalent to adding StringEnd() to the
  end of the expression.)  The default value is False to
  retain backward compatibility.

Inspired by MANY requests over the years, most recently by
  ecir-hana on the pyparsing wiki!

- Added new operator '-' for composing grammar sequences. '-'
  behaves just like '+' in creating And expressions, but '-'
  is used to mark grammar structures that should stop parsing
  immediately and report a syntax error, rather than just
  backtracking to the last successful parse and trying another
  alternative.  For instance, running the following code:

port_definition = Keyword("port") + '=' + Word(nums)
    entity_definition = Keyword("entity") + "{" +
        Optional(port_definition) + "}"

entity_definition.parseString("entity { port 100 }")

pyparsing fails to detect the missing '=' in the port definition.
  But, since this expression is optional, pyparsing then proceeds
  to try to match the closing '}' of the entity_definition.  Not
  finding it, pyparsing reports that there was no '}' after the '{'
  character.  Instead, we would like pyparsing to parse the 'port'
  keyword, and if not followed by an equals sign and an integer,
  to signal this as a syntax error.

This can now be done simply by changing the port_definition to:

port_definition = Keyword("port") - '=' + Word(nums)

Now after successfully parsing 'port', pyparsing must also find
  an equals sign and an integer, or it will raise a fatal syntax
  exception.

By judicious insertion of '-' operators, a pyparsing developer
  can have their grammar report much more informative syntax error
  messages.

Patches and suggestions proposed by several contributors on
  the pyparsing mailing list and wiki - special thanks to
  Eike Welk and Thomas/Poldy on the pyparsing wiki!

- Added indentedBlock helper method, to encapsulate the parse
  actions and indentation stack management needed to keep track of
  indentation levels.  Use indentedBlock to define grammars for
  indentation-based grouping grammars, like Python's.

indentedBlock takes up to 3 parameters:
    - blockStatementExpr - expression defining syntax of statement
        that is repeated within the indented block
    - indentStack - list created by caller to manage indentation
        stack (multiple indentedBlock expressions
        within a single grammar should share a common indentStack)
    - indent - boolean indicating whether block must be indented
        beyond the current level; set to False for block of
        left-most statements (default=True)

A valid block must contain at least one indented statement.

- Fixed bug in nestedExpr in which ignored expressions needed
  to be set off with whitespace.  Reported by Stefaan Himpe,
  nice catch!

- Expanded multiplication of an expression by a tuple, to
  accept tuple values of None:
  . expr*(n,None) or expr*(n,) is equivalent
    to expr*n + ZeroOrMore(expr)
    (read as "at least n instances of expr")
  . expr*(None,n) is equivalent to expr*(0,n)
    (read as "0 to n instances of expr")
  . expr*(None,None) is equivalent to ZeroOrMore(expr)
  . expr*(1,None) is equivalent to OneOrMore(expr)

Note that expr*(None,n) does not raise an exception if
  more than n exprs exist in the input stream; that is,
  expr*(None,n) does not enforce a maximum number of expr
  occurrences.  If this behavior is desired, then write
  expr*(None,n) + ~expr

- Added None as a possible operator for operatorPrecedence.
  None signifies "no operator", as in multiplying m times x
  in "y=mx+b".

- Fixed bug in Each, reported by Michael Ramirez, in which the
  order of terms in the Each affected the parsing of the results.
  Problem was due to premature grouping of the expressions in
  the overall Each during grammar construction, before the
  complete Each was defined.  Thanks, Michael!

- Also fixed bug in Each in which Optional's with default values
  were not getting the defaults added to the results of the
  overall Each expression.

- Fixed a bug in Optional in which results names were not
  assigned if a default value was supplied.

- Cleaned up Py3K compatibility statements, including exception
  construction statements, and better equivalence between _ustr
  and basestring, and __nonzero__ and __bool__.

Version 1.4.11 - February, 2008
-------------------------------
- With help from Robert A. Clark, this version of pyparsing
  is compatible with Python 3.0a3.  Thanks for the help,
  Robert!

- Added WordStart and WordEnd positional classes, to support
  expressions that must occur at the start or end of a word.
  Proposed by piranha on the pyparsing wiki, good idea!

- Added matchOnlyAtCol helper parser action, to simplify
  parsing log or data files that have optional fields that are
  column dependent.  Inspired by a discussion thread with
  hubritic on comp.lang.python.

- Added withAttribute.ANY_VALUE as a match-all value when using
  withAttribute.  Used to ensure that an attribute is present,
  without having to match on the actual attribute value.

- Added get() method to ParseResults, similar to dict.get().
  Suggested by new pyparsing user, Alejandro Dubrovksy, thanks!

- Added '==' short-cut to see if a given string matches a
  pyparsing expression.  For instance, you can now write:

integer = Word(nums)
    if "123" == integer:
       # do something

print [ x for x in "123 234 asld".split() if x==integer ]
    # prints ['123', '234']

- Simplified the use of nestedExpr when using an expression for
  the opening or closing delimiters.  Now the content expression
  will not have to explicitly negate closing delimiters.  Found
  while working with dfinnie on GHOP Task #277, thanks!

- Fixed bug when defining ignorable expressions that are
  later enclosed in a wrapper expression (such as ZeroOrMore,
  OneOrMore, etc.) - found while working with Prabhu
  Gurumurthy, thanks Prahbu!

- Fixed bug in withAttribute in which keys were automatically
  converted to lowercase, making it impossible to match XML
  attributes with uppercase characters in them.  Using with-
  Attribute requires that you reference attributes in all
  lowercase if parsing HTML, and in correct case when parsing
  XML.

- Changed '<<' operator on Forward to return None, since this
  is really used as a pseudo-assignment operator, not as a
  left-shift operator.  By returning None, it is easier to
  catch faulty statements such as a << b | c, where precedence
  of operations causes the '|' operation to be performed
  *after* inserting b into a, so no alternation is actually
  implemented.  The correct form is a << (b | c).  With this
  change, an error will be reported instead of silently
  clipping the alternative term.  (Note: this may break some
  existing code, but if it does, the code had a silent bug in
  it anyway.)  Proposed by wcbarksdale on the pyparsing wiki,
  thanks!

- Several unit tests were added to pyparsing's regression
  suite, courtesy of the Google Highly-Open Participation
  Contest.  Thanks to all who administered and took part in
  this event!

Version 1.4.10 - December 9, 2007
---------------------------------
- Fixed bug introduced in v1.4.8, parse actions were called for
  intermediate operator levels, not just the deepest matching
  operation level.  Again, big thanks to Torsten Marek for
  helping isolate this problem!

Version 1.4.9 - December 8, 2007
--------------------------------
- Added '*' multiplication operator support when creating
  grammars, accepting either an integer, or a two-integer
  tuple multiplier, as in:
    ipAddress = Word(nums) + ('.'+Word(nums))*3
    usPhoneNumber = Word(nums) + ('-'+Word(nums))*(1,2)
  If multiplying by a tuple, the two integer values represent
  min and max multiples.  Suggested by Vincent of eToy.com,
  great idea, Vincent!

- Fixed bug in nestedExpr, original version was overly greedy!
  Thanks to Michael Ramirez for raising this issue.

- Fixed internal bug in ParseResults - when an item was deleted,
  the key indices were not updated.  Thanks to Tim Mitchell for
  posting a bugfix patch to the SF bug tracking system!

- Fixed internal bug in operatorPrecedence - when the results of
  a right-associative term were sent to a parse action, the wrong
  tokens were sent.  Reported by Torsten Marek, nice job!

- Added pop() method to ParseResults.  If pop is called with an
  integer or with no arguments, it will use list semantics and
  update the ParseResults' list of tokens.  If pop is called with
  a non-integer (a string, for instance), then it will use dict
  semantics and update the ParseResults' internal dict.
  Suggested by Donn Ingle, thanks Donn!

- Fixed quoted string built-ins to accept '\xHH' hex characters
  within the string.

Version 1.4.8 - October, 2007
-----------------------------
- Added new helper method nestedExpr to easily create expressions
  that parse lists of data in nested parentheses, braces, brackets,
  etc.

- Added withAttribute parse action helper, to simplify creating
  filtering parse actions to attach to expressions returned by
  makeHTMLTags and makeXMLTags.  Use withAttribute to qualify a
  starting tag with one or more required attribute values, to avoid
  false matches on common tags such as <TD> or <DIV>.

- Added new examples nested.py and withAttribute.py to demonstrate
  the new features.

- Added performance speedup to grammars using operatorPrecedence,
  instigated by Stefan Reichör - thanks for the feedback, Stefan!

- Fixed bug/typo when deleting an element from a ParseResults by
  using the element's results name.

- Fixed whitespace-skipping bug in wrapper classes (such as Group,
  Suppress, Combine, etc.) and when using setDebug(), reported by
  new pyparsing user dazzawazza on SourceForge, nice job!

- Added restriction to prevent defining Word or CharsNotIn expressions
  with minimum length of 0 (should use Optional if this is desired),
  and enhanced docstrings to reflect this limitation.  Issue was
  raised by Joey Tallieu, who submitted a patch with a slightly
  different solution.  Thanks for taking the initiative, Joey, and
  please keep submitting your ideas!

- Fixed bug in makeHTMLTags that did not detect HTML tag attributes
  with no '= value' portion (such as "<td nowrap>"), reported by
  hamidh on the pyparsing wiki - thanks!

- Fixed minor bug in makeHTMLTags and makeXMLTags, which did not
  accept whitespace in closing tags.

Version 1.4.7 - July, 2007
--------------------------
- NEW NOTATION SHORTCUT: ParserElement now accepts results names using
  a notational shortcut, following the expression with the results name
  in parentheses.  So this:

stats = "AVE:" + realNum.setResultsName("average") + \
            "MIN:" + realNum.setResultsName("min") + \
            "MAX:" + realNum.setResultsName("max")

can now be written as this:

stats = "AVE:" + realNum("average") + \
            "MIN:" + realNum("min") + \
            "MAX:" + realNum("max")

The intent behind this change is to make it simpler to define results
  names for significant fields within the expression, while keeping
  the grammar syntax clean and uncluttered.

- Fixed bug when packrat parsing is enabled, with cached ParseResults
  being updated by subsequent parsing.  Reported on the pyparsing
  wiki by Kambiz, thanks!

- Fixed bug in operatorPrecedence for unary operators with left
  associativity, if multiple operators were given for the same term.

- Fixed bug in example simpleBool.py, corrected precedence of "and" vs.
  "or" operations.

- Fixed bug in Dict class, in which keys were converted to strings
  whether they needed to be or not.  Have narrowed this logic to
  convert keys to strings only if the keys are ints (which would
  confuse __getitem__ behavior for list indexing vs. key lookup).

- Added ParserElement method setBreak(), which will invoke the pdb
  module's set_trace() function when this expression is about to be
  parsed.

- Fixed bug in StringEnd in which reading off the end of the input
  string raises an exception - should match.  Resolved while
  answering a question for Shawn on the pyparsing wiki.

Version 1.4.6 - April, 2007
---------------------------
- Simplified constructor for ParseFatalException, to support common
  exception construction idiom:
    raise ParseFatalException, "unexpected text: 'Spanish Inquisition'"

- Added method getTokensEndLoc(), to be called from within a parse action,
  for those parse actions that need both the starting *and* ending
  location of the parsed tokens within the input text.

- Enhanced behavior of keepOriginalText so that named parse fields are
  preserved, even though tokens are replaced with the original input
  text matched by the current expression.  Also, cleaned up the stack
  traversal to be more robust.  Suggested by Tim Arnold - thanks, Tim!

- Fixed subtle bug in which countedArray (and similar dynamic
  expressions configured in parse actions) failed to match within Or,
  Each, FollowedBy, or NotAny.  Reported by Ralf Vosseler, thanks for
  your patience, Ralf!

- Fixed Unicode bug in upcaseTokens and downcaseTokens parse actions,
  scanString, and default debugging actions; reported (and patch submitted)
  by Nikolai Zamkovoi, spasibo!

- Fixed bug when saving a tuple as a named result.  The returned
  token list gave the proper tuple value, but accessing the result by
  name only gave the first element of the tuple.  Reported by
  Poromenos, nice catch!

- Fixed bug in makeHTMLTags/makeXMLTags, which failed to match tag
  attributes with namespaces.

- Fixed bug in SkipTo when setting include=True, to have the skipped-to
  tokens correctly included in the returned data.  Reported by gunars on
  the pyparsing wiki, thanks!

- Fixed typobug in OnceOnly.reset method, omitted self argument.
  Submitted by eike welk, thanks for the lint-picking!

- Added performance enhancement to Forward class, suggested by
  akkartik on the pyparsing Wiki discussion, nice work!

- Added optional asKeyword to Word constructor, to indicate that the
  given word pattern should be matched only as a keyword, that is, it
  should only match if it is within word boundaries.

- Added S-expression parser to examples directory.

- Added macro substitution example to examples directory.

- Added holaMundo.py example, excerpted from Marco Alfonso's blog -
  muchas gracias, Marco!

- Modified internal cyclic references in ParseResults to use weakrefs;
  this should help reduce the memory footprint of large parsing
  programs, at some cost to performance (3-5%). Suggested by bca48150 on
  the pyparsing wiki, thanks!

- Enhanced the documentation describing the vagaries and idiosyncracies
  of parsing strings with embedded tabs, and the impact on:
  . parse actions
  . scanString
  . col and line helper functions
  (Suggested by eike welk in response to some unexplained inconsistencies
  between parsed location and offsets in the input string.)

- Cleaned up internal decorators to preserve function names,
  docstrings, etc.

Version 1.4.5 - December, 2006
------------------------------
- Removed debugging print statement from QuotedString class.  Sorry
  for not stripping this out before the 1.4.4 release!

- A significant performance improvement, the first one in a while!
  For my Verilog parser, this version of pyparsing is about double the
  speed - YMMV.

- Added support for pickling of ParseResults objects.  (Reported by
  Jeff Poole, thanks Jeff!)

- Fixed minor bug in makeHTMLTags that did not recognize tag attributes
  with embedded '-' or '_' characters.  Also, added support for
  passing expressions to makeHTMLTags and makeXMLTags, and used this
  feature to define the globals anyOpenTag and anyCloseTag.

- Fixed error in alphas8bit, I had omitted the y-with-umlaut character.

- Added punc8bit string to complement alphas8bit - it contains all the
  non-alphabetic, non-blank 8-bit characters.

- Added commonHTMLEntity expression, to match common HTML "ampersand"
  codes, such as "&lt;", "&gt;", "&amp;", "&nbsp;", and "&quot;".  This
  expression also defines a results name 'entity', which can be used
  to extract the entity field (that is, "lt", "gt", etc.).  Also added
  built-in parse action replaceHTMLEntity, which can be attached to
  commonHTMLEntity to translate "&lt;", "&gt;", "&amp;", "&nbsp;", and
  "&quot;" to "<", ">", "&", " ", and "'".

- Added example, htmlStripper.py, that strips HTML tags and scripts
  from HTML pages.  It also translates common HTML entities to their
  respective characters.

Version 1.4.4 - October, 2006
-------------------------------
- Fixed traceParseAction decorator to also trap and record exception
  returns from parse actions, and to handle parse actions with 0,
  1, 2, or 3 arguments.

- Enhanced parse action normalization to support using classes as
  parse actions; that is, the class constructor is called at parse
  time and the __init__ function is called with 0, 1, 2, or 3
  arguments.  If passing a class as a parse action, the __init__
  method must use one  of the valid parse action parameter list
  formats. (This technique is useful when using pyparsing to compile
  parsed text into a series of application objects - see the new
  example simpleBool.py.)

- Fixed bug in ParseResults when setting an item using an integer
  index. (Reported by Christopher Lambacher, thanks!)

- Fixed whitespace-skipping bug, patch submitted by Paolo Losi -
  grazie, Paolo!

- Fixed bug when a Combine contained an embedded Forward expression,
  reported by cie on the pyparsing wiki - good catch!

- Fixed listAllMatches bug, when a listAllMatches result was
  nested within another result. (Reported by don pasquale on
  comp.lang.python, well done!)

- Fixed bug in ParseResults items() method, when returning an item
  marked as listAllMatches=True

- Fixed bug in definition of cppStyleComment (and javaStyleComment)
  in which '//' line comments were not continued to the next line
  if the line ends with a '\'.  (Reported by eagle-eyed Ralph
  Corderoy!)

- Optimized re's for cppStyleComment and quotedString for better
  re performance - also provided by Ralph Corderoy, thanks!

- Added new example, indentedGrammarExample.py, showing how to
  define a grammar using indentation to show grouping (as Python
  does for defining statement nesting).  Instigated by an e-mail
  discussion with Andrew Dalke, thanks Andrew!

- Added new helper operatorPrecedence (based on e-mail list discussion
  with Ralph Corderoy and Paolo Losi), to facilitate definition of
  grammars for expressions with unary and binary operators.  For
  instance, this grammar defines a 6-function arithmetic expression
  grammar, with unary plus and minus, proper operator precedence,and
  right- and left-associativity:

expr = operatorPrecedence( operand,
        [("!", 1, opAssoc.LEFT),
         ("^", 2, opAssoc.RIGHT),
         (oneOf("+ -"), 1, opAssoc.RIGHT),
         (oneOf("* /"), 2, opAssoc.LEFT),
         (oneOf("+ -"), 2, opAssoc.LEFT),]
        )

Also added example simpleArith.py and simpleBool.py to provide
  more detailed code samples using this new helper method.

- Added new helpers matchPreviousLiteral and matchPreviousExpr, for
  creating adaptive parsing expressions that match the same content
  as was parsed in a previous parse expression.  For instance:

first = Word(nums)
        matchExpr = first + ":" + matchPreviousLiteral(first)

will match "1:1", but not "1:2".  Since this matches at the literal
  level, this will also match the leading "1:1" in "1:10".

In contrast:

first = Word(nums)
        matchExpr = first + ":" + matchPreviousExpr(first)

will *not* match the leading "1:1" in "1:10"; the expressions are
  evaluated first, and then compared, so "1" is compared with "10".

- Added keepOriginalText parse action.  Sometimes pyparsing's
  whitespace-skipping leaves out too much whitespace.  Adding this
  parse action will restore any internal whitespace for a parse
  expression.  This is especially useful when defining expressions
  for scanString or transformString applications.

- Added __add__ method for ParseResults class, to better support
  using Python sum built-in for summing ParseResults objects returned
  from scanString.

- Added reset method for the new OnlyOnce class wrapper for parse
  actions (to allow a grammar to be used multiple times).

- Added optional maxMatches argument to scanString and searchString,
  to short-circuit scanning after 'n' expression matches are found.

Version 1.4.3 - July, 2006
------------------------------
- Fixed implementation of multiple parse actions for an expression
  (added in 1.4.2).
  . setParseAction() reverts to its previous behavior, setting
    one (or more) actions for an expression, overwriting any
    action or actions previously defined
  . new method addParseAction() appends one or more parse actions
    to the list of parse actions attached to an expression
  Now it is harder to accidentally append parse actions to an
  expression, when what you wanted to do was overwrite whatever had
  been defined before.  (Thanks, Jean-Paul Calderone!)

- Simplified interface to parse actions that do not require all 3
  parse action arguments.  Very rarely do parse actions require more
  than just the parsed tokens, yet parse actions still require all
  3 arguments including the string being parsed and the location
  within the string where the parse expression was matched.  With this
  release, parse actions may now be defined to be called as:
  . fn(string,locn,tokens)  (the current form)
  . fn(locn,tokens)
  . fn(tokens)
  . fn()
  The setParseAction and addParseAction methods will internally decorate
  the provided parse actions with compatible wrappers to conform to
  the full (string,locn,tokens) argument sequence.

- REMOVED SUPPORT FOR RETURNING PARSE LOCATION FROM A PARSE ACTION.
  I announced this in March, 2004, and gave a final warning in the last
  release.  Now you can return a tuple from a parse action, and it will
  be treated like any other return value (i.e., the tuple will be
  substituted for the incoming tokens passed to the parse action,
  which is useful when trying to parse strings into tuples).

- Added setFailAction method, taking a callable function fn that
  takes the arguments fn(s,loc,expr,err) where:
  . s - string being parsed
  . loc - location where expression match was attempted and failed
  . expr - the parse expression that failed
  . err - the exception thrown
  The function returns no values.  It may throw ParseFatalException
  if it is desired to stop parsing immediately.
  (Suggested by peter21081944 on wikispaces.com)

- Added class OnlyOnce as helper wrapper for parse actions.  OnlyOnce
  only permits a parse action to be called one time, after which
  all subsequent calls throw a ParseException.

- Added traceParseAction decorator to help debug parse actions.
  Simply insert "@traceParseAction" ahead of the definition of your
  parse action, and each invocation will be displayed, along with
  incoming arguments, and returned value.

- Fixed bug when copying ParserElements using copy() or
  setResultsName().  (Reported by Dan Thill, great catch!)

- Fixed bug in asXML() where token text contains <, >, and &
  characters - generated XML now escapes these as &lt;, &gt; and
  &amp;.  (Reported by Jacek Sieka, thanks!)

- Fixed bug in SkipTo() when searching for a StringEnd(). (Reported
  by Pete McEvoy, thanks Pete!)

- Fixed "except Exception" statements, the most critical added as part
  of the packrat parsing enhancement.  (Thanks, Erick Tryzelaar!)

- Fixed end-of-string infinite looping on LineEnd and StringEnd
  expressions.  (Thanks again to Erick Tryzelaar.)

- Modified setWhitespaceChars to return self, to be consistent with
  other ParserElement modifiers. (Suggested by Erick Tryzelaar.)

- Fixed bug/typo in new ParseResults.dump() method.

- Fixed bug in searchString() method, in which only the first token of
  an expression was returned.  searchString() now returns a
  ParseResults collection of all search matches.

- Added example program removeLineBreaks.py, a string transformer that
  converts text files with hard line-breaks into one with line breaks
  only between paragraphs.

- Added example program listAllMatches.py, to illustrate using the
  listAllMatches option when specifying results names (also shows new
  support for passing lists to oneOf).

- Added example program linenoExample.py, to illustrate using the
  helper methods lineno, line, and col, and returning objects from a
  parse action.

- Added example program parseListString.py, to which can parse the
  string representation of a Python list back into a true list.  Taken
  mostly from my PyCon presentation examples, but now with support
  for tuple elements, too!

Version 1.4.2 - April 1, 2006 (No foolin'!)
-------------------------------------------
- Significant speedup from memoizing nested expressions (a technique
  known as "packrat parsing"), thanks to Chris Lesniewski-Laas!  Your
  mileage may vary, but my Verilog parser almost doubled in speed to
  over 600 lines/sec!

This speedup may break existing programs that use parse actions that
  have side-effects.  For this reason, packrat parsing is disabled when
  you first import pyparsing.  To activate the packrat feature, your
  program must call the class method ParserElement.enablePackrat().  If
  your program uses psyco to "compile as you go", you must call
  enablePackrat before calling psyco.full().  If you do not do this,
  Python will crash.  For best results, call enablePackrat() immediately
  after importing pyparsing.

- Added new helper method countedArray(expr), for defining patterns that
  start with a leading integer to indicate the number of array elements,
  followed by that many elements, matching the given expr parse
  expression.  For instance, this two-liner:
    wordArray = countedArray(Word(alphas))
    print wordArray.parseString("3 Practicality beats purity")[0]
  returns the parsed array of words:
    ['Practicality', 'beats', 'purity']
  The leading token '3' is suppressed, although it is easily obtained
  from the length of the returned array.
  (Inspired by e-mail discussion with Ralf Vosseler.)

- Added support for attaching multiple parse actions to a single
  ParserElement. (Suggested by Dan "Dang" Griffith - nice idea, Dan!)

- Added support for asymmetric quoting characters in the recently-added
  QuotedString class.  Now you can define your own quoted string syntax
  like "<<This is a string in double angle brackets.>>".  To define
  this custom form of QuotedString, your code would define:
    dblAngleQuotedString = QuotedString('<<',endQuoteChar='>>')
  QuotedString also supports escaped quotes, escape character other
  than '\', and multiline.

- Changed the default value returned internally by Optional, so that
  None can be used as a default value.  (Suggested by Steven Bethard -
  I finally saw the light!)

- Added dump() method to ParseResults, to make it easier to list out
  and diagnose values returned from calling parseString.

- A new example, a search query string parser, submitted by Steven
  Mooij and Rudolph Froger - a very interesting application, thanks!

- Added an example that parses the BNF in Python's Grammar file, in
  support of generating Python grammar documentation. (Suggested by
  J H Stovall.)

- A new example, submitted by Tim Cera, of a flexible parser module,
  using a simple config variable to adjust parsing for input formats
  that have slight variations - thanks, Tim!

- Added an example for parsing Roman numerals, showing the capability
  of parse actions to "compile" Roman numerals into their integer
  values during parsing.

- Added a new docs directory, for additional documentation or help.
  Currently, this includes the text and examples from my recent
  presentation at PyCon.

- Fixed another typo in CaselessKeyword, thanks Stefan Behnel.

- Expanded oneOf to also accept tuples, not just lists.  This really
  should be sufficient...

- Added deprecation warnings when tuple is returned from a parse action.
  Looking back, I see that I originally deprecated this feature in March,
  2004, so I'm guessing people really shouldn't have been using this
  feature - I'll drop it altogether in the next release, which will
  allow users to return a tuple from a parse action (which is really
  handy when trying to reconstuct tuples from a tuple string
  representation!).

Version 1.4.1 - February, 2006
------------------------------
- Converted generator expression in QuotedString class to list
  comprehension, to retain compatibility with Python 2.3. (Thanks, Titus
  Brown for the heads-up!)

- Added searchString() method to ParserElement, as an alternative to
  using "scanString(instring).next()[0][0]" to search through a string
  looking for a substring matching a given parse expression. (Inspired by
  e-mail conversation with Dave Feustel.)

- Modified oneOf to accept lists of strings as well as a single string
  of space-delimited literals.  (Suggested by Jacek Sieka - thanks!)

- Removed deprecated use of Upcase in pyparsing test code. (Also caught by
  Titus Brown.)

- Removed lstrip() call from Literal - too aggressive in stripping
  whitespace which may be valid for some grammars.  (Point raised by Jacek
  Sieka).  Also, made Literal more robust in the event of passing an empty
  string.

- Fixed bug in replaceWith when returning None.

- Added cautionary documentation for Forward class when assigning a
  MatchFirst expression, as in:
    fwdExpr << a | b | c
  Precedence of operators causes this to be evaluated as:
    (fwdExpr << a) | b | c
  thereby leaving b and c out as parseable alternatives.  Users must
  explicitly group the values inserted into the Forward:
    fwdExpr << (a | b | c)
  (Suggested by Scot Wilcoxon - thanks, Scot!)

Version 1.4 - January 18, 2006
------------------------------
- Added Regex class, to permit definition of complex embedded expressions
  using regular expressions. (Enhancement provided by John Beisley, great
  job!)

- Converted implementations of Word, oneOf, quoted string, and comment
  helpers to utilize regular expression matching.  Performance improvements
  in the 20-40% range.

- Added QuotedString class, to support definition of non-standard quoted
  strings (Suggested by Guillaume Proulx, thanks!)

- Added CaselessKeyword class, to streamline grammars with, well, caseless
  keywords (Proposed by Stefan Behnel, thanks!)

- Fixed bug in SkipTo, when using an ignoreable expression. (Patch provided
  by Anonymous, thanks, whoever-you-are!)

- Fixed typo in NoMatch class. (Good catch, Stefan Behnel!)

- Fixed minor bug in _makeTags(), using string.printables instead of
  pyparsing.printables.

- Cleaned up some of the expressions created by makeXXXTags helpers, to
  suppress extraneous <> characters.

- Added some grammar definition-time checking to verify that a grammar is
  being built using proper ParserElements.

- Added examples:
  . LAparser.py - linear algebra C preprocessor (submitted by Mike Ellis,
    thanks Mike!)
  . wordsToNum.py - converts word description of a number back to
    the original number (such as 'one hundred and twenty three' -> 123)
  . updated fourFn.py to support unary minus, added BNF comments

Version 1.3.3 - September 12, 2005
----------------------------------
- Improved support for Unicode strings that would be returned using
  srange.  Added greetingInKorean.py example, for a Korean version of
  "Hello, World!" using Unicode. (Thanks, June Kim!)

- Added 'hexnums' string constant (nums+"ABCDEFabcdef") for defining
  hexadecimal value expressions.

- NOTE: ===THIS CHANGE MAY BREAK EXISTING CODE===
  Modified tag and results definitions returned by makeHTMLTags(),
  to better support the looseness of HTML parsing.  Tags to be
  parsed are now caseless, and keys generated for tag attributes are
  now converted to lower case.

Formerly, makeXMLTags("XYZ") would return a tag with results
  name of "startXYZ", this has been changed to "startXyz".  If this
  tag is matched against '<XYZ Abc="1" DEF="2" ghi="3">', the
  matched keys formerly would be "Abc", "DEF", and "ghi"; keys are
  now converted to lower case, giving keys of "abc", "def", and
  "ghi".  These changes were made to try to address the lax
  case sensitivity agreement between start and end tags in many
  HTML pages.

No changes were made to makeXMLTags(), which assumes more rigorous
  parsing rules.

Also, cleaned up case-sensitivity bugs in closing tags, and
  switched to using Keyword instead of Literal class for tags.
  (Thanks, Steve Young, for getting me to look at these in more
  detail!)

- Added two helper parse actions, upcaseTokens and downcaseTokens,
  which will convert matched text to all uppercase or lowercase,
  respectively.

- Deprecated Upcase class, to be replaced by upcaseTokens parse
  action.

- Converted messages sent to stderr to use warnings module, such as
  when constructing a Literal with an empty string, one should use
  the Empty() class or the empty helper instead.

- Added ' ' (space) as an escapable character within a quoted
  string.

- Added helper expressions for common comment types, in addition
  to the existing cStyleComment (/*...*/) and htmlStyleComment
  ()
  . dblSlashComment = // ... (to end of line)
  . cppStyleComment = cStyleComment or dblSlashComment
  . javaStyleComment = cppStyleComment
  . pythonStyleComment = # ... (to end of line)

Version 1.3.2 - July 24, 2005
-----------------------------
- Added Each class as an enhanced version of And.  'Each' requires
  that all given expressions be present, but may occur in any order.
  Special handling is provided to group ZeroOrMore and OneOrMore
  elements that occur out-of-order in the input string.  You can also
  construct 'Each' objects by joining expressions with the '&'
  operator.  When using the Each class, results names are strongly
  recommended for accessing the matched tokens. (Suggested by Pradam
  Amini - thanks, Pradam!)

- Stricter interpretation of 'max' qualifier on Word elements.  If the
  'max' attribute is specified, matching will fail if an input field
  contains more than 'max' consecutive body characters.  For example,
  previously, Word(nums,max=3) would match the first three characters
  of '0123456', returning '012' and continuing parsing at '3'.  Now,
  when constructed using the max attribute, Word will raise an
  exception with this string.

- Cleaner handling of nested dictionaries returned by Dict.  No
  longer necessary to dereference sub-dictionaries as element [0] of
  their parents.
  === NOTE: THIS CHANGE MAY BREAK SOME EXISTING CODE, BUT ONLY IF
  PARSING NESTED DICTIONARIES USING THE LITTLE-USED DICT CLASS ===
  (Prompted by discussion thread on the Python Tutor list, with
  contributions from Danny Yoo, Kent Johnson, and original post by
  Liam Clarke - thanks all!)

Version 1.3.1 - June, 2005
----------------------------------
- Added markInputline() method to ParseException, to display the input
  text line location of the parsing exception. (Thanks, Stefan Behnel!)

- Added setDefaultKeywordChars(), so that Keyword definitions using a
  custom keyword character set do not all need to add the keywordChars
  constructor argument (similar to setDefaultWhitespaceChars()).
  (suggested by rzhanka on the SourceForge pyparsing forum.)

- Simplified passing debug actions to setDebugAction().  You can now
  pass 'None' for a debug action if you want to take the default
  debug behavior.  To suppress a particular debug action, you can pass
  the pyparsing method nullDebugAction.

- Refactored parse exception classes, moved all behavior to
  ParseBaseException, and the former ParseException is now a subclass of
  ParseBaseException.  Added a second subclass, ParseFatalException, as
  a subclass of ParseBaseException.  User-defined parse actions can raise
  ParseFatalException if a data inconsistency is detected (such as a
  begin-tag/end-tag mismatch), and this will stop all parsing immediately.
  (Inspired by e-mail thread with Michele Petrazzo - thanks, Michelle!)

- Added helper methods makeXMLTags and makeHTMLTags, that simplify the
  definition of XML or HTML tag parse expressions for a given tagname.
  Both functions return a pair of parse expressions, one for the opening
  tag (that is, '<tagname>') and one for the closing tag ('</tagname>').
  The opening tagame also recognizes any attribute definitions that have
  been included in the opening tag, as well as an empty tag (one with a
  trailing '/', as in '<BODY/>' which is equivalent to '<BODY></BODY>').
  makeXMLTags uses stricter XML syntax for attributes, requiring that they
  be enclosed in double quote characters - makeHTMLTags is more lenient,
  and accepts single-quoted strings or any contiguous string of characters
  up to the next whitespace character or '>' character.  Attributes can
  be retrieved as dictionary or attribute values of the returned results
  from the opening tag.

- Added example minimath2.py, a refinement on fourFn.py that adds
  an interactive session and support for variables.  (Thanks, Steven Siew!)

- Added performance improvement, up to 20% reduction!  (Found while working
  with Wolfgang Borgert on performance tuning of his TTCN3 parser.)

- And another performance improvement, up to 25%, when using scanString!
  (Found while working with Henrik Westlund on his C header file scanner.)

- Updated UML diagrams to reflect latest class/method changes.

Version 1.3 - March, 2005
----------------------------------
- Added new Keyword class, as a special form of Literal.  Keywords
  must be followed by whitespace or other non-keyword characters, to
  distinguish them from variables or other identifiers that just
  happen to start with the same characters as a keyword.  For instance,
  the input string containing "ifOnlyIfOnly" will match a Literal("if")
  at the beginning and in the middle, but will fail to match a
  Keyword("if").  Keyword("if") will match only strings such as "if only"
  or "if(only)". (Proposed by Wolfgang Borgert, and Berteun Damman
  separately requested this on comp.lang.python - great idea!)

- Added setWhitespaceChars() method to override the characters to be
  skipped as whitespace before matching a particular ParseElement.  Also
  added the class-level method setDefaultWhitespaceChars(), to allow
  users to override the default set of whitespace characters (space,
  tab, newline, and return) for all subsequently defined ParseElements.
  (Inspired by Klaas Hofstra's inquiry on the Sourceforge pyparsing
  forum.)

- Added helper parse actions to support some very common parse
  action use cases:
  . replaceWith(replStr) - replaces the matching tokens with the
    provided replStr replacement string; especially useful with
    transformString()
  . removeQuotes - removes first and last character from string enclosed
    in quotes (note - NOT the same as the string strip() method, as only
    a single character is removed at each end)

- Added copy() method to ParseElement, to make it easier to define
  different parse actions for the same basic parse expression.  (Note, copy
  is implicitly called when using setResultsName().)

(The following changes were posted to CVS as Version 1.2.3 -
  October-December, 2004)

- Added support for Unicode strings in creating grammar definitions.
  (Big thanks to Gavin Panella!)

- Added constant alphas8bit to include the following 8-bit characters:
    ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõöøùúûüýþ

- Added srange() function to simplify definition of Word elements, using
  regexp-like '[A-Za-z0-9]' syntax.  This also simplifies referencing
  common 8-bit characters.

- Fixed bug in Dict when a single element Dict was embedded within another
  Dict. (Thanks Andy Yates for catching this one!)

- Added 'formatted' argument to ParseResults.asXML().  If set to False,
  suppresses insertion of whitespace for pretty-print formatting.  Default
  equals True for backward compatibility.

- Added setDebugActions() function to ParserElement, to allow user-defined
  debugging actions.

- Added support for escaped quotes (either in \', \", or doubled quote
  form) to the predefined expressions for quoted strings. (Thanks, Ero
  Carrera!)

- Minor performance improvement (~5%) converting "char in string" tests
  to "char in dict". (Suggested by Gavin Panella, cool idea!)

Version 1.2.2 - September 27, 2004
----------------------------------
- Modified delimitedList to accept an expression as the delimiter, instead
  of only accepting strings.

- Modified ParseResults, to convert integer field keys to strings (to
  avoid confusion with list access).

- Modified Combine, to convert all embedded tokens to strings before
  combining.

- Fixed bug in MatchFirst in which parse actions would be called for
  expressions that only partially match. (Thanks, John Hunter!)

- Fixed bug in fourFn.py example that fixes right-associativity of ^
  operator. (Thanks, Andrea Griffini!)

- Added class FollowedBy(expression), to look ahead in the input string
  without consuming tokens.

- Added class NoMatch that never matches any input. Can be useful in
  debugging, and in very specialized grammars.

- Added example pgn.py, for parsing chess game files stored in Portable
  Game Notation. (Thanks, Alberto Santini!)

Version 1.2.1 - August 19, 2004
-------------------------------
- Added SkipTo(expression) token type, simplifying grammars that only
  want to specify delimiting expressions, and want to match any characters
  between them.

- Added helper method dictOf(key,value), making it easier to work with
  the Dict class. (Inspired by Pavel Volkovitskiy, thanks!).

- Added optional argument listAllMatches (default=False) to
  setResultsName().  Setting listAllMatches to True overrides the default
  modal setting of tokens to results names; instead, the results name
  acts as an accumulator for all matching tokens within the local
  repetition group. (Suggested by Amaury Le Leyzour - thanks!)

- Fixed bug in ParseResults, throwing exception when trying to extract
  slice, or make a copy using [:]. (Thanks, Wilson Fowlie!)

- Fixed bug in transformString() when the input string contains <TAB>'s
  (Thanks, Rick Walia!).

- Fixed bug in returning tokens from un-Grouped And's, Or's and
  MatchFirst's, where too many tokens would be included in the results,
  confounding parse actions and returned results.

- Fixed bug in naming ParseResults returned by And's, Or's, and Match
  First's.

- Fixed bug in LineEnd() - matching this token now correctly consumes
  and returns the end of line "\n".

- Added a beautiful example for parsing Mozilla calendar files (Thanks,
  Petri Savolainen!).

- Added support for dynamically modifying Forward expressions during
  parsing.

Version 1.2 - 20 June 2004
--------------------------
- Added definition for htmlComment to help support HTML scanning and
  parsing.

- Fixed bug in generating XML for Dict classes, in which trailing item was
  duplicated in the output XML.

- Fixed release bug in which scanExamples.py was omitted from release
  files.

- Fixed bug in transformString() when parse actions are not defined on the
  outermost parser element.

- Added example urlExtractor.py, as another example of using scanString
  and parse actions.

Version 1.2beta3 - 4 June 2004
------------------------------
- Added White() token type, analogous to Word, to match on whitespace
  characters.  Use White in parsers with significant whitespace (such as
  configuration file parsers that use indentation to indicate grouping).
  Construct White with a string containing the whitespace characters to be
  matched.  Similar to Word, White also takes optional min, max, and exact
  parameters.

- As part of supporting whitespace-signficant parsing, added parseWithTabs()
  method to ParserElement, to override the default behavior in parseString
  of automatically expanding tabs to spaces.  To retain tabs during
  parsing, call parseWithTabs() before calling parseString(), parseFile() or
  scanString(). (Thanks, Jean-Guillaume Paradis for catching this, and for
  your suggestions on whitespace-significant parsing.)

- Added transformString() method to ParseElement, as a complement to
  scanString().  To use transformString, define a grammar and attach a parse
  action to the overall grammar that modifies the returned token list.
  Invoking transformString() on a target string will then scan for matches,
  and replace the matched text patterns according to the logic in the parse
  action.  transformString() returns the resulting transformed string.
  (Note: transformString() does *not* automatically expand tabs to spaces.)
  Also added scanExamples.py to the examples directory to show sample uses of
  scanString() and transformString().

- Removed group() method that was introduced in beta2.  This turns out NOT to
  be equivalent to nesting within a Group() object, and I'd prefer not to sow
  more seeds of confusion.

- Fixed behavior of asXML() where tags for groups were incorrectly duplicated.
  (Thanks, Brad Clements!)

- Changed beta version message to display to stderr instead of stdout, to
  make asXML() easier to use.  (Thanks again, Brad.)

Version 1.2beta2 - 19 May 2004
------------------------------
- *** SIMPLIFIED API *** - Parse actions that do not modify the list of tokens
  no longer need to return a value.  This simplifies those parse actions that
  use the list of tokens to update a counter or record or display some of the
  token content; these parse actions can simply end without having to specify
  'return toks'.

- *** POSSIBLE API INCOMPATIBILITY *** - Fixed CaselessLiteral bug, where the
  returned token text was not the original string (as stated in the docs),
  but the original string converted to upper case.  (Thanks, Dang Griffith!)
  **NOTE: this may break some code that relied on this erroneous behavior.
  Users should scan their code for uses of CaselessLiteral.**

- *** POSSIBLE CODE INCOMPATIBILITY *** - I have renamed the internal
  attributes on ParseResults from 'dict' and 'list' to '__tokdict' and
  '__toklist', to avoid collisions with user-defined data fields named 'dict'
  and 'list'.  Any client code that accesses these attributes directly will
  need to be modified.  Hopefully the implementation of methods such as keys(),
  items(), len(), etc. on ParseResults will make such direct attribute
  accessess unnecessary.

- Added asXML() method to ParseResults.  This greatly simplifies the process
  of parsing an input data file and generating XML-structured data.

- Added getName() method to ParseResults.  This method is helpful when
  a grammar specifies ZeroOrMore or OneOrMore of a MatchFirst or Or
  expression, and the parsing code needs to know which expression matched.
  (Thanks, Eric van der Vlist, for this idea!)

- Added items() and values() methods to ParseResults, to better support using
  ParseResults as a Dictionary.

- Added parseFile() as a convenience function to parse the contents of an
  entire text file.  Accepts either a file name or a file object.  (Thanks
  again, Dang!)

- Added group() method to And, Or, and MatchFirst, as a short-cut alternative
  to enclosing a construct inside a Group object.

- Extended fourFn.py to support exponentiation, and simple built-in functions.

- Added EBNF parser to examples, including a demo where it parses its own
  EBNF!  (Thanks to Seo Sanghyeon!)

- Added Delphi Form parser to examples, dfmparse.py, plus a couple of
  sample Delphi forms as tests.  (Well done, Dang!)

- Another performance speedup, 5-10%, inspired by Dang!  Plus about a 20%
  speedup, by pre-constructing and cacheing exception objects instead of
  constructing them on the fly.

- Fixed minor bug when specifying oneOf() with 'caseless=True'.

- Cleaned up and added a few more docstrings, to improve the generated docs.

Version 1.1.2 - 21 Mar 2004
---------------------------
- Fixed minor bug in scanString(), so that start location is at the start of
  the matched tokens, not at the start of the whitespace before the matched
  tokens.

- Inclusion of HTML documentation, generated using Epydoc.  Reformatted some
  doc strings to better generate readable docs. (Beautiful work, Ed Loper,
  thanks for Epydoc!)

- Minor performance speedup, 5-15%

- And on a process note, I've used the unittest module to define a series of
  unit tests, to help avoid the embarrassment of the version 1.1 snafu.

Version 1.1.1 - 6 Mar 2004
--------------------------
- Fixed critical bug introduced in 1.1, which broke MatchFirst(!) token
  matching.
  **THANK YOU, SEO SANGHYEON!!!**

- Added "from future import __generators__" to permit running under
  pre-Python 2.3.

- Added example getNTPservers.py, showing how to use pyparsing to extract
  a text pattern from the HTML of a web page.

Version 1.1 - 3 Mar 2004
-------------------------
- ***Changed API*** - While testing out parse actions, I found that the value
  of loc passed in was not the starting location of the matched tokens, but
  the location of the next token in the list.  With this version, the location
  passed to the parse action is now the starting location of the tokens that
  matched.

A second part of this change is that the return value of parse actions no
  longer needs to return a tuple containing both the location and the parsed
  tokens (which may optionally be modified); parse actions only need to return
  the list of tokens.  Parse actions that return a tuple are deprecated; they
  will still work properly for conversion/compatibility, but this behavior will
  be removed in a future version.

- Added validate() method, to help diagnose infinite recursion in a grammar tree.
  validate() is not 100% fool-proof, but it can help track down nasty infinite
  looping due to recursively referencing the same grammar construct without some
  intervening characters.

- Cleaned up default listing of some parse element types, to more closely match
  ordinary BNF.  Instead of the form <classname>:[contents-list], some changes
  are:
  . And(token1,token2,token3) is "{ token1 token2 token3 }"
  . Or(token1,token2,token3) is "{ token1 ^ token2 ^ token3 }"
  . MatchFirst(token1,token2,token3) is "{ token1 | token2 | token3 }"
  . Optional(token) is "[ token ]"
  . OneOrMore(token) is "{ token }..."
  . ZeroOrMore(token) is "[ token ]..."

- Fixed an infinite loop in oneOf if the input string contains a duplicated
  option. (Thanks Brad Clements)

- Fixed a bug when specifying a results name on an Optional token. (Thanks
  again, Brad Clements)

- Fixed a bug introduced in 1.0.6 when I converted quotedString to use
  CharsNotIn; I accidentally permitted quoted strings to span newlines.  I have
  fixed this in this version to go back to the original behavior, in which
  quoted strings do *not* span newlines.

- Fixed minor bug in HTTP server log parser. (Thanks Jim Richardson)

Version 1.0.6 -  13 Feb 2004
----------------------------
- Added CharsNotIn class (Thanks, Lee SangYeong).  This is the opposite of
  Word, in that it is constructed with a set of characters *not* to be matched.
  (This enhancement also allowed me to clean up and simplify some of the
  definitions for quoted strings, cStyleComment, and restOfLine.)

- **MINOR API CHANGE** - Added joinString argument to the __init__ method of
  Combine (Thanks, Thomas Kalka).  joinString defaults to "", but some
  applications might choose some other string to use instead, such as a blank
  or newline.  joinString was inserted as the second argument to __init__,
  so if you have code that specifies an adjacent value, without using
  'adjacent=', this code will break.

- Modified LineStart to recognize the start of an empty line.

- Added optional caseless flag to oneOf(), to create a list of CaselessLiteral
  tokens instead of Literal tokens.

- Added some enhancements to the SQL example:
  . Oracle-style comments (Thanks to Harald Armin Massa)
  . simple WHERE clause

- Minor performance speedup - 5-15%

Version 1.0.5 -  19 Jan 2004
----------------------------
- Added scanString() generator method to ParseElement, to support regex-like
  pattern-searching

- Added items() list to ParseResults, to return named results as a
  list of (key,value) pairs

- Fixed memory overflow in asList() for deeply nested ParseResults (Thanks,
  Sverrir Valgeirsson)

- Minor performance speedup - 10-15%

Version 1.0.4 -  8 Jan 2004
---------------------------
- Added positional tokens StringStart, StringEnd, LineStart, and LineEnd

- Added commaSeparatedList to pre-defined global token definitions; also added
  commasep.py to the examples directory, to demonstrate the differences between
  parsing comma-separated data and simple line-splitting at commas

- Minor API change: delimitedList does not automatically enclose the
  list elements in a Group, but makes this the responsibility of the caller;
  also, if invoked using 'combine=True', the list delimiters are also included
  in the returned text (good for scoped variables, such as a.b.c or a::b::c, or
  for directory paths such as a/b/c)

- Performance speed-up again, 30-40%

- Added httpServerLogParser.py to examples directory, as this is
  a common parsing task

Version 1.0.3 - 23 Dec 2003
---------------------------
- Performance speed-up again, 20-40%

- Added Python distutils installation setup.py, etc. (thanks, Dave Kuhlman)

Version 1.0.2 - 18 Dec 2003
---------------------------
- **NOTE: Changed API again!!!** (for the last time, I hope)

+ Renamed module from parsing to pyparsing, to better reflect Python
    linkage.

- Also added dictExample.py to examples directory, to illustrate
  usage of the Dict class.

Version 1.0.1 - 17 Dec 2003
---------------------------
- **NOTE:  Changed API!**

+ Renamed 'len' argument on Word.__init__() to 'exact'

- Performance speed-up, 10-30%

Version 1.0.0 - 15 Dec 2003
---------------------------
- Initial public release

Version 0.1.1 thru 0.1.17 - October-November, 2003
--------------------------------------------------
- initial development iterations:
    - added Dict, Group
    - added helper methods oneOf, delimitedList
    - added helpers quotedString (and double and single), restOfLine, cStyleComment
    - added MatchFirst as an alternative to the slower Or
    - added UML class diagram
    - fixed various logic bugs

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