CHANGELOG.md

Arpeggio changelog

All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

Everything that is documented in the official docs is considered the part of the public API.

Backward incompatible changes are marked with (BIC). These changes are the reason for the major version increase so when upgrading between major versions please take a look at related PRs and issues and see if the change affects you.

Unreleased

• Fix parsing of regex rules in peg and cleanpeg syntaxes (#125). Thanks @smurfix for reporting (#123).

• (BIC) Removed support for Python 3.6. The minimal supported version is 3.7.

• Added sypport for Python 3.12.

• Migrated to pyproject.toml for project configuration.

• Use ruff instead of flake8 for linting. ruff can also be used for code formating.

• Use flit for package building and publishing.

• fix!: non-consuming alternatives in ordered choices (BIC) #96. Thanks @vprat, @mettta and @stanislaw for reporting the issue.

  Now, ordered choice alternatives may succeed even if no input is consumed. This means that any infallible expression e.g. Optional in an ordered choice will always succeed and no further choices will ever be tried.

  Issue #101 when implemented will detect and report these invalid grammars.

  For the rationale for this change see this discussion.

• fix!: do not use soft failure in zero/one-or-more (BIC). This is related to #96.

  Warning: Previously, we used a kind of "soft failures" of parsing expression which were based on treating None returned from child expressions in repetitions (ZeroOrMore, OneOrMore) to signalize soft failure and avoid infinite loops if the inner expression succeeds without consuming the input. While convenient in some cases it has lead to confusion (see #96). Now, the parser behaves consistently by always using NoMatch to signalize failure.

  This means that now is perfectly possible to make a pathologic grammar that will make the parser loop endlessly. For example:

  def grammar():
      ZeroOrMore(a), EOF
  def a():
      RegExMatch('.*')

  Rule a is a RegExMatch which may succeed by matching empty string thus inducing ZeroOrMore to repeat endlessly when we reach the end of input.

  In the future Arpeggio might introduce a way to detect these situations during parser construction but for now if you find yourself in a situation that the parser has stuck watch out for non-consuming matches (especially regex matches) inside repetitions or turn on debugging output to see why the parser is looping.

  Issue #101 when implemented will detect and report these invalid grammars.

• fix: #98 suppressed match in zero-or-more #98. Thanks @vpavlu for reporting the issue.

• fix: empty comments in .peg files hid the next line, commented or not (#124). Thanks @smurfix for the fix.

2.0.2 (released: 2023-07-09)

• fix: drop deprecated setup_requires and tests_require #116. Thanks @kloczek.

2.0.1 (released: 2023-07-09)

• fix: replace \n with \\n in error reports for matches #99. Thanks @mettta and @stanislaw.

2.0.0 (released: 2022-03-20)

• Added eval_attrs call to NoMatch exceptions (ebfd60). See the docs.
• Dropped support for deprecated Python versions. The lowest supported version is 3.6. (BIC)

1.10.2 (released: 2021-04-25)

• Added EditorConfig configuration (#77). Thanks KOLANICH@GitHub
• Fixed parsing of version from setup.py when global encoding isn't UTF-8 (#86). Thanks neirbowj@GitHub
• Fix repetition termination on a successful empty separator match (#92).

1.10.1 (released: 2020-11-01)

• Fix packaging, exclude examples from wheel. Thanks mgorny@GitHub (#83)

1.10.0 (released: 2020-11-01)

• Fix reporting duplicate rule names in NoMatch exception (a1f14bede)
• Raise AttributeError when accessing unexisting rule name on parse tree node. (#82)
• Added tree_str method to parse tree nodes for nice string representation of parse trees. (#76)
• Added parse tree node suppression support and overriding of special Python rule syntax. (#76)
• UnorderedGroup matching made deterministic (#73)

v1.9.2 (released: 2019-10-05)

• Added explicit Python versions in setup.py classifiers (#65)
• Removed pytest version constraint and fixed tests to work with both 5.x and older versions. (#57)

v1.9.1 (released: 2019-09-28)

• Lowered the required pytest version for running tests as we'll still support Python 2.7 until its EOL.
• Fixed problem with OrderedChoice which hasn't maintained skipws/ws state. #61 Reported at textX/textX#205
• Various fixes in the docs, docstrings and examples. Thanks mcepl@GitHub and zetaraku@GitHub.
• docs support for different versions thanks to mike

v1.9.0 (released: 2018-07-19)

• Added extra_info param to Terminal for additional information. Used by textX.
• Fixed problem with version string reading in non-UTF-8 environments. Thanks sebix@GitHub.

v1.8.0 (released: 2018-05-16)

• Fixed issue #43. Backward incompatible change for cleanpeg comment syntax.
• Added file parser param used for DebugPrinter to allow the output stream to be changed from stdout. This allows doctests to continue to work. Thanks ianmmoir@GitHub.

v1.7.1 (released: 2018-02-10)

• Fixed bug in comment parsing optimization.

v1.7 (released: 2017-11-17)

• Added re_flag parameter to RegExMatch constructor. Thanks Aluriak@GitHub.
• Fix in grammar language docs. Thanks schmittlauch@GitHub.
• Small fixes in examples.

v1.6.1 (released: 2017-05-15)

• Fixed bug in unordered group with optional subexpressions.

v1.6 (released: 2017-05-15)

• Dropped support for Python 3.2.
• Improved error reporting (especially for Not Parsing Expression).
• line,col attributes are now available on NoMatch exception.
• Fixed issue #31 - a subtle bug in empty nested parses.
• Issue #32 - improvements and fixes in escape sequences support. Thanks smbolton@github!
• Added position_end attribute on parse tree nodes with the position in the input stream where the given match ends.
• Added support for unordered groups (UnorderedGroup class). See the docs.
• Support for separator expression in repetitions (sep parameter). See the docs.
• Various code/docs cleanup.

v1.5 (released: 2016-05-31)

• Significant performance improvements (see textX issue #22)
• Added new performance tests to keep track of both speed and memory consumption.
• Memoization is disabled by default. Added memoization parameter to the Parser instantiation.

v1.4 (released: 2016-05-05)

• Support for parse tree node suppression. Used for textX - operator.
• Render - for suppressed ParsingExpression on dot graphs.

v1.3.1 (released: 2016-04-28)

• Some smaller changes/fixes in internal API.
• Smaller updates to docs.

v1.3 (released: 2016-03-03)

• Improved error reporting (issue #25). On the point of error all possible matches will be reported now.
• Fixed bug with regex that succeeds with empty string in repetitions (issue #26).
• Various fixes in examples and the docs.
• Significant performance improvement for parsing of large files. This fix also changes handling of ^ in regex matches. Now ^ will match on the beginning of the input and beginning of new line.
• Performance improvements in comment parsing.

v1.2.1 (released: 2015-11-10)

• Fixing error reporting that wasn't taking into account successful matches in optionals.
• Slightly improved debug prints.

v1.2 (released: 2015-10-31)

• Docs has been migrated to MkDocs and restructured. A lot of new additions have been made and three full length tutorials.
• Examples refactoring and restructuring.
• Fixing whitespace handling for str matches loaded from external PEG file.
• Added travis configuration to test for 2.7, 3.2-3.5 Python versions.

v1.1 (released: 2015-08-27)

• Reworking NoMatch exception handling code.
• Some optimization tweaks. Removed unnecessary exception handling.
• Improved debug printings.
• Fix in ordered choice with optional matches (issue #20)
• Fixing parser invalid state after handling non-string inputs (thanks Santi Villalba - sdvillal@github)
• Some fixes in conversion to utf-8 encoding.
• Various improvements and additions to the tests.

v1.0 (released: 2015-04-14)

• Functionally identical to v0.10. It is just the time to go production-stable ;)

v0.10 (released: 2015-02-10)

• Documentation - http://arpeggio.readthedocs.org/en/latest/
• autokwd parser parameter. Match on word boundaries for keyword-like string matches.
• skipws and ws parameters for Sequence.
• Improvements in error reporting.

v0.9 (released: 2014-10-16)

• Visitor pattern support for semantic analysis - issue 15
• Alternative PEG syntax (arpeggio.cleanpeg module) - issue 11
• Support for unicode in grammars.
• Python 2/3 compatibility for unicodes.

v0.8 (released: 2014-09-20)

• Support for eolterm modifier in repetitions.
• Support for custom regex match string representation.
• Various bugfixes.
• Improved debug messages.

v0.7 (released: 2014-08-16)

• Parse tree navigation
• Better semantic action debugging output.
• Tests reorganization and cleanup.
• Examples cleanup.
• Reference resolving unification in parser constructions.
• Default semantic actions and automatic terminal suppressing during semantic analysis.
• PEG language support refactoring and code cleaning.

v0.6 (released: 2014-06-06)

• Support for Python 3 (issue #7)
• Matched rules available as attributes of non-terminals (issue #2)
• Lexical rules support (issue #6). Implemented as Combine decorator.

v0.5 (released: 2014-02-02)

• Bugfixes
• Examples
• Parse tree reduction for one-child non-terminals.

v0.1-dev (released: 2009-09-15) - Initial release

• Basic error reporting.
• Basic support for comments handling (needs refactoring)
• Raw parse tree.
• Support for semantic actions with ability to transform parse tree to semantic representation - aka Abstract Semantic Graphs (see examples).