Add CHANGELOG.md

.pymarkdown

@@ -6,6 +6,9 @@
     "md013": {
       "line_length": 79,
       "strict": true
+    },
+    "md024": {
+      "siblings_only": true
     }
   }
-}
+}

CHANGELOG.md

@@ -0,0 +1,65 @@
+# Changelog
+
+## v0.7.0
+
+### Added
+
+- Added comparison operators to `NumericSequence`.
+- Added one-based indexing support to `Recurrence`.
+- Added a factory for building a `Series` from an existing sequence.
+- Added `Fraction` support to the numeric type system.
+- Added sequence rule retrieval.
+- Added support for negative indexing in slice bounds for zero-indexed finite
+  sequences.
+
+### Changed
+
+- Renamed the `Real` numeric type alias from `Number`.
+- Restricted `combine()` to same-type operands.
+
+### Removed
+
+- Removed complex number support from `NumericSequence`.
+- Removed `shift_by()` and `shift_to()` sequence transformations.
+
+### Fixed
+
+- Fixed type-checking issues when applying arithmetic and slicing to derived
+  sequences.
+- Fixed reverse slicing of infinite sequences without an explicit stop.
+
+## v0.6.0
+
+### Added
+
+- Added BooleanSequence for boolean-valued sequences.
+
+## v0.5.0
+
+### Added
+
+- Added Series for partial-sum sequences.
+
+## v0.4.0
+
+### Added
+
+- Added NumericRecurrence for recursively defined numeric sequences.
+
+## v0.3.0
+
+### Added
+
+- Added Recurrence for sequences defined by recurrence rules.
+
+## v0.2.0
+
+### Added
+
+- Added NumericSequence with arithmetic operations.
+
+## v0.1.0
+
+### Added
+
+- Added the initial calculus package implementation.

README.md

@@ -233,9 +233,10 @@ print(4 * leibniz[1000])
 │   └── test_utils.py                 # Pytest test suite for utility functions
 ├── .gitignore
 ├── .pymarkdown
+├── CHANGELOG.md
 ├── LICENSE
 ├── README.md
-├── TODO.md                           # Planned work
+├── TODO.md
 ├── pyproject.toml                    # Project configuration
 ├── pytest.ini                        # Pytest configuration for test imports
 └── requirements-dev.txt              # Development and CI dependencies

TODO.md

@@ -17,10 +17,6 @@
 
 - Identify opportunities to use decorators.
 
-## Documentation
-
-- Add `CHANGELOG.md`.
-
 ## Environment
 
 - Set up GitHub Issues for tracking bugs and planned work.

calculus/__init__.py

@@ -7,7 +7,7 @@
 from .sequence import Sequence
 from .series import Series
 
-__version__ = "0.6.0"
+__version__ = "0.7.0"
 
 __all__ = [
     "BooleanSequence",

docs/STYLE.md

@@ -18,6 +18,20 @@ of the library.
   files, PR descriptions): wrap at 79 characters.
 - Fill the space: avoid wrapping lines prematurely.
 
+## Changelog
+
+Changelog entries describe user-facing changes rather than implementation
+details.
+
+- Group entries by release version.
+- Keep releases in chronological order, newest first.
+- Within each release, group entries under Added, Changed, Removed, Fixed, or
+  Deprecated subheadings, as applicable.
+- Within each group in a release, list entries in the order they were added,
+  oldest first.
+- Add new entries only under the next unreleased version.
+- Do not modify existing entries unless correcting factual errors.
+
 ## Git
 
 **<u>Caution!</u>** These conventions diverge from Conventional Commits and