Pyparsing 3.0.0b1

• API CHANGE
  Diagnostic flags have been moved to an enum, pyparsing.Diagnostics, and they are enabled through module-level methods:

  • pyparsing.enable_diag()
  • pyparsing.disable_diag()
  • pyparsing.enable_all_warnings()

• API CHANGE
  Most previous SyntaxWarnings that were warned when using pyparsing classes incorrectly have been converted to TypeError and ValueError exceptions, consistent with Python calling conventions. All warnings warned by diagnostic flags have been converted from SyntaxWarnings to UserWarnings.

• To support parsers that are intended to generate native Python collection types such as lists and dicts, the Group and Dict classes now accept an additional boolean keyword argument aslist and asdict respectively. See the jsonParser.py example in the pyparsing/examples source directory for how to return types as ParseResults and as Python collection types, and the distinctions in working with the different types.

  In addition parse actions that must return a value of list type (which would normally be converted internally to a ParseResults) can override this default behavior by returning their list wrapped in the new ParseResults.List class:

  # this parse action tries to return a list, but pyparsing
  # will convert to a ParseResults
  def return_as_list_but_still_get_parse_results(tokens):
      return tokens.asList()
  
  # this parse action returns the tokens as a list, and pyparsing will
  # maintain its list type in the final parsing results
  def return_as_list(tokens):
      return ParseResults.List(tokens.asList())
  

  This is the mechanism used internally by the Group class when defined using aslist=True.

• A new IndentedBlock class is introduced, to eventually replace the current indentedBlock helper method. The interface is largely the same, however, the new class manages its own internal indentation stack, so it is no longer necessary to maintain an external indentStack variable.

• API CHANGE
  Added cache_hit keyword argument to debug actions. Previously, if packrat parsing was enabled, the debug methods were not called in the event of cache hits. Now these methods will be called, with an added argument cache_hit=True.

  If you are using packrat parsing and enable debug on expressions using a custom debug method, you can add the cache_hit=False keyword argument,
  and your method will be called on packrat cache hits. If you choose not to add this keyword argument, the debug methods will fail silently, behaving as they did previously.

• When using setDebug with packrat parsing enabled, packrat cache hits will now be included in the output, shown with a leading '*'. (Previously, cache hits and responses were not included in debug output.) For those using custom debug actions, see the previous item regarding an optional API change for those methods.

• setDebug output will also show more details about what expression is about to be parsed (the current line of text being parsed, and the current parse position):

    Match integer at loc 0(1,1)
      1 2 3
      ^
    Matched integer -> ['1']
  

  The current debug location will also be indicated after whitespace has been skipped (was previously inconsistent, reported in Issue #244, by Frank Goyens, thanks!).

• Modified the repr() output for ParseResults to include the class name as part of the output. This is to clarify for new pyparsing users who misread the repr output as a tuple of a list and a dict. pyparsing results will now read like:

  ParseResults(['abc', 'def'], {'qty': 100}]
  

  instead of just:

  (['abc', 'def'], {'qty': 100}]
  

• Fixed bugs in Each when passed OneOrMore or ZeroOrMore expressions:
  . first expression match could be enclosed in an extra nesting level
  . out-of-order expressions now handled correctly if mixed with required expressions
  . results names are maintained correctly for these expressions

• Fixed traceback trimming, and added ParserElement.verbose_traceback save/restore to reset_pyparsing_context().

• Default string for Word expressions now also include indications of min and max length specification, if applicable, similar to regex length specifications:

    Word(alphas)             -> "W:(A-Za-z)"
    Word(nums)               -> "W:(0-9)"
    Word(nums, exact=3)      -> "W:(0-9){3}"
    Word(nums, min=2)        -> "W:(0-9){2,...}"
    Word(nums, max=3)        -> "W:(0-9){1,3}"
    Word(nums, min=2, max=3) -> "W:(0-9){2,3}"
  

  For expressions of the Char class (similar to Word(..., exact=1), the expression is simply the character range in parentheses:

    Char(nums)               -> "(0-9)"
    Char(alphas)             -> "(A-Za-z)"
  

• Removed copy() override in Keyword class which did not preserve definition of ident chars from the original expression. PR #233 submitted by jgrey4296, thanks!

• In addition to pyparsing.__version__, there is now also a pyparsing.__version_info__, following the same structure and field names as in sys.version_info.

Pyparsing 3.0.0a2

Version 3.0.0a2 - June, 2020

• Summary of changes for 3.0.0 can be found in "What's New in Pyparsing 3.0.0" documentation.

• API CHANGE
  Changed result returned when parsing using countedArray, the array items are no longer returned in a doubly-nested list.

• An excellent new enhancement is the new railroad diagram generator for documenting pyparsing parsers:

    import pyparsing as pp
    from pyparsing.diagram import to_railroad, railroad_to_html
    from pathlib import Path
  
    # define a simple grammar for parsing street addresses such
    # as "123 Main Street"
    #     number word...
    number = pp.Word(pp.nums).setName("number")
    name = pp.Word(pp.alphas).setName("word")[1, ...]
  
    parser = number("house_number") + name("street")
    parser.setName("street address")
  
    # construct railroad track diagram for this parser and
    # save as HTML
    rr = to_railroad(parser)
    Path('parser_rr_diag.html').write_text(railroad_to_html(rr))
  

  Very nice work provided by Michael Milton, thanks a ton!

• Enhanced default strings created for Word expressions, now showing string ranges if possible. Word(alphas) would formerly print as W:(ABCD...), now prints as W:(A-Za-z).

• Added ignoreWhitespace(recurse:bool = True) and added a recurse argument to leaveWhitespace, both added to provide finer control over pyparsing's whitespace skipping. Also contributed by Michael Milton.

• The unicode range definitions for the various languages were recalculated by interrogating the unicodedata module by character name, selecting characters that contained that language in their Unicode name. (Issue #227)

  Also, pyparsing_unicode.Korean was renamed to Hangul (Korean is also defined as a synonym for compatibility).

• Enhanced ParseResults dump() to show both results names and list subitems. Fixes bug where adding a results name would hide lower-level structures in the ParseResults.

• Added new __diag__ warnings:

  "warn_on_parse_using_empty_Forward" - warns that a Forward has been included in a grammar, but no expression was attached to it using '<<=' or '<<'

  "warn_on_assignment_to_Forward" - warns that a Forward has been created, but was probably later overwritten by erroneously using '=' instead of '<<=' (this is a common mistake when using Forwards) (currently not working on PyPy)

• Added ParserElement.recurse() method to make it simpler for grammar utilities to navigate through the tree of expressions in a pyparsing grammar.

• Fixed bug in ParseResults repr() which showed all matching entries for a results name, even if listAllMatches was set to False when creating the ParseResults originally. Reported by Nicholas42 on GitHub, good catch! (Issue #205)

• Modified refactored modules to use relative imports, as pointed out by setuptools project member jaraco, thank you!

• Off-by-one bug found in the roman_numerals.py example, a bug that has been there for about 14 years! PR submitted by Jay Pedersen, nice catch!

• A simplified Lua parser has been added to the examples (lua_parser.py).

• Added make_diagram.py to the examples directory to demonstrate creation of railroad diagrams for selected pyparsing examples. Also restructured some examples to make their parsers importable without running their embedded tests.

Pyparsing 2.4.7

Version 2.4.7 - April, 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

Pyparsing 2.4.6

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):
  ...

Pyparsing 2.4.5

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'.

Pyparsing 2.4.4

Check-in bug in Pyparsing 2.4.3 that raised UserWarnings was masked by stdout buffering in unit tests - fixed.

Pyparsing 2.4.3

Version 2.4.3 - November, 2019

(Backport of selected critical items from 3.0.0 development branch.)

• 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 pyparsing 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

Pyparsing 2.4.2

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!

Pyparsing 2.4.1.1

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))
  

  to

  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.

Pyparsing 2.4.2a1

Release candidate for 2.4.2:

• FIxes incorrect implementation of expr[…] as OneOrMore, changed to ZeroOrMore
• Fixes __getitem__-induced iterability for ParserElement class
• __diag__ flags are now all False by default