Change Log

Breaking: Dropped support for Python versions 3.6, 3.7, 3.8 and 3.9.

Breaking: Changed the precedence of operators to be more aligned with common programming languages.

Breaking: The Debug REPL utility now requires development dependencies to be installed.

Breaking: BYTES literals now throw exceptions for invalid escape sequences

Breaking: Removed setup.py; project metadata now lives entirely in pyproject.toml (PEP 517/621).

Breaking: The rule_engine.ast module no longer re-exports names from rule_engine.types (e.g. DataType, coerce_value); import them from rule_engine or rule_engine.types directly.

Migrated the development workflow and CI from pipenv to uv.

Added support for raw STRING literals using the r prefix (e.g. r'\w+').

Vendored the PLY dependency under rule_engine._vendor.ply — the upstream project is unmaintained, so the copy removes an external install requirement and silences third-party vulnerability reports targeting it.

Added the new OBJECT compound data type for user-defined schemas with named, typed attributes. See the OBJECT section in the Data Types page for details.

• Use reference() (or the self shorthand sentinel) for self-referential and mutually-recursive schemas.

• Attribute access is validated at parse time against the declared schema.

• Item access (obj["name"]) and containment checks ("name" in obj) on OBJECT values are rejected at parse time.

• SET(OBJECT(...)) is rejected at construction; use ARRAY(OBJECT(...)) instead

• A custom accessor callable can be specified per OBJECT type (default: getattr()).

• Added from_dataclass() and type_resolver_from_dataclass() for deriving OBJECT schemas and type_resolvers automatically from Python dataclass() definitions, including nullability for Optional fields and self / mutually-recursive references (closes #55).

• Added from_sqlalchemy() and type_resolver_from_sqlalchemy() for deriving OBJECT schemas and type_resolvers from SQLAlchemy ORM mapped classes. Columns, relationships, and cycles between mutually-related classes are all expanded automatically. SQLAlchemy is an optional dependency; the import is deferred until these entry points are called.

• The from_dataclass and from_sqlalchemy entry points (and their type_resolver_from_* companions) accept a strict keyword argument. The default strict=True raises ValueError on any field / column whose type cannot be mapped to a Rule Engine data type; strict=False falls back to UNDEFINED.

Added ObjectAttributeError, a subclass of AttributeResolutionError, raised when an attribute is not found in an OBJECT schema

Promoted nullability to a first-class type-system construct via the new NULLABLE one-argument type constructor. See the NULLABLE section in the Data Types page for the full semantics.

• from_type() maps Python’s Optional[T] / T | None to NULLABLE(from_type(T)).

• from_dataclass() and from_sqlalchemy() wrap nullable fields, columns, and scalar relationships in NULLABLE(T); type_resolver_from_dataclass() and type_resolver_from_sqlalchemy() preserve the wrappers through to the top-level symbol types.

• Compound element and value types (ARRAY, SET, MAPPING) store NULLABLE(T) directly when the member may be None.

• AST operators reject NULLABLE operands at parse time wherever None has no meaningful semantics: arithmetic, ordered comparisons, the regex operators, bitwise and bitwise-shift operators, unary minus, containment, attribute access, item access, slicing, and function arguments all raise EvaluationError (or FunctionCallError for function arguments) with a message pointing at the discharge operators. Equality (==, !=), logical connectives (and, or, not), ternary expressions, and safe-navigation operators remain lenient.

• A new null-coalesce operator left ?? right discharges NULLABLE(T) to T. Existing safe attribute (&.) and item (&[) accessors still apply to nullable receivers and are the only access forms that do.

Deprecated: The attributes_nullable kwarg on OBJECT and the value_type_nullable kwarg on ARRAY, SET, and MAPPING now emit DeprecationWarning. Wrap the relevant attribute or element type in NULLABLE instead. The kwargs will be removed in v6.0.

Deprecated: Accessing MAPPING keys via dot syntax (mapping.key) now emits a MappingAttributeLookupDeprecation warning. Use bracket syntax (mapping["key"]) instead. This fallback will be removed in v6.0. Set Context(mapping_attribute_lookup=False) to opt out now.

StringSyntaxError is now raised for invalid string literals

FunctionCallError is now raised when a typed function returns an incompatible value

Added the new BYTES data type

Added some new data attributes

• Added starts_with and ends_with to ARRAY, and STRING

Breaking: Changed STRING.to_ary to return an array of characters instead of splitting the string

• Use the new builtin $split function to split a string on whitespace into an array of words

Breaking: Changed Context to use keyword-only arguments

Breaking: Dropped support for Python versions 3.4 and 3.5

Breaking: Invalid floating point literals now raise FloatSyntaxError instead of RuleSyntaxError

Breaking: Moved rule_engine.engine.Builtins to rule_engine.builtins.Builtins

Added the new FUNCTION data type

Switched the FLOAT datatype to use Python’s Decimal from float internally

Reserved the if, elif, else, for and while keywords for future use, they can no longer be used as symbol names

Added some new data attributes

• Added ceiling, floor and to_str to FLOAT

Added support for arithmetic comparisons for all currently supported data types

Added support for proper type hinting of builtin symbols

Added the $re_groups builtin symbol for extracting groups from a regular expression match

Added some new data attributes

• Added to_ary to STRING

• Added to_int and to_flt to STRING

Added coverage reporting to Travis-CI

Changed DataType. from an enum to a custom class

Improvements for the ARRAY data type

• Added get[item] support for arrays, allowing items to be retrieved by index

• Added ability for specifying the member type and optionally null

Added proper support for attributes

Added a change log

Added additional information to the Graphviz output

Added the new ARRAY data type

Started using Travis-CI

• Added automatic unit testing using Travis-CI

• Added automatic deployment of documentation using Travis-CI

Removed the resolver conversion functions

• Removed to_recursive_resolver in favor of attributes

• Removed to_default_resolver in favor of the default_value kwarg to __init__()