`errors`

This module contains the exceptions raised by the package.

Data

UNDEFINED = UNDEFINED: A sentinel value to specify that something is undefined. When evaluated, the value is falsy.

Added in version 2.0.0.

Exceptions

exception ArithmeticError(message: str = '')[source]

Bases: EvaluationError

An error raised when there is an issue performing an arithmetic operation.

Added in version 5.0.0.

exception AttributeResolutionError(attribute_name: str, object_: Any, thing: Any = UNDEFINED, suggestion: str | None = None)[source]

Bases: EvaluationError

An error raised when an attribute can not be resolved to a value.

Added in version 2.0.0.

__init__(attribute_name: str, object_: Any, thing: Any = UNDEFINED, suggestion: str | None = None) → None[source]

Parameters:

attribute_name (str) – The name of the symbol that can not be resolved.
object – The value that attribute_name was used as an attribute for.
thing – The root-object that was used to resolve object.
suggestion (str) – An optional suggestion for a valid attribute name.

Changed in version 3.2.0: Added the suggestion parameter.

attribute_name: The name of the symbol that can not be resolved.

object: The value that attribute_name was used as an attribute for.

suggestion: An optional suggestion for a valid attribute name.

thing: The root-object that was used to resolve object.

exception AttributeTypeError(attribute_name: str, object_type: _DataTypeDef, is_value: Any, is_type: _DataTypeDef, expected_type: _DataTypeDef)[source]

Bases: EvaluationError

An error raised when an attribute with type information is resolved to a Python value that is not of that type.

__init__(attribute_name: str, object_type: _DataTypeDef, is_value: Any, is_type: _DataTypeDef, expected_type: _DataTypeDef) → None[source]

Parameters:

attribute_name (str) – The name of the symbol that can not be resolved.
object_type – The value that attribute_name was used as an attribute for.
is_value – The native Python value of the incompatible attribute.
is_type – The rule-engine type of the incompatible attribute.
expected_type – The rule-engine type that was expected for this attribute.

attribute_name: The name of the attribute that is of an incompatible type.

expected_type: The rule-engine type that was expected for this attribute.

is_type: The rule-engine type of the incompatible attribute.

is_value: The native Python value of the incompatible attribute.

object_type: The object on which the attribute was resolved.

exception BytesSyntaxError(message: str, value: str)[source]

Bases: SyntaxError

An error raised for issues regarding the use of improperly formatted bytes expressions.

Added in version 4.5.0.

__init__(message: str, value: str) → None[source]

Parameters:

message (str) – A text description of what error occurred.
value (str) – The bytes value which contains the syntax error which caused this exception to be raised.

value: The bytes value which contains the syntax error which caused this exception to be raised.

exception DatetimeSyntaxError(message: str, value: str)[source]

Bases: SyntaxError

An error raised for issues regarding the use of improperly formatted datetime expressions.

__init__(message: str, value: str) → None[source]

Parameters:

message (str) – A text description of what error occurred.
value (str) – The datetime value which contains the syntax error which caused this exception to be raised.

value: The datetime value which contains the syntax error which caused this exception to be raised.

exception FloatSyntaxError(message: str, value: str)[source]

Bases: SyntaxError

An error raised for issues regarding the use of improperly formatted float expressions.

Added in version 4.0.0.

__init__(message: str, value: str) → None[source]

Parameters:

message (str) – A text description of what error occurred.
value (str) – The float value which contains the syntax error which caused this exception to be raised.

value: The float value which contains the syntax error which caused this exception to be raised.

exception EngineError(message: str = '')[source]

Bases: Exception

The base exception class from which other exceptions within this package inherit.

__init__(message: str = '') → None[source]

Parameters:: message (str) – A text description of what error occurred.

message: A text description of what error occurred.

exception EvaluationError(message: str = '')[source]

Bases: EngineError

An error raised for issues which occur while the rule is being evaluated. This can occur at parse time while AST nodes are being evaluated during the reduction phase.

exception FunctionCallError(message: str, error: BaseException | None = None, function_name: str | None = None)[source]

Bases: EvaluationError

An error raised when there is an issue calling a function.

Added in version 4.0.0.

__init__(message: str, error: BaseException | None = None, function_name: str | None = None) → None[source]

Parameters:: message (str) – A text description of what error occurred.

error: The exception from which this error was triggered.

exception LookupError(container: Any, item: Any)[source]

Bases: EvaluationError

An error raised when a lookup operation fails to obtain and item from a container. This is analogous to a combination of Python’s builtin IndexError and KeyError exceptions.

Added in version 2.4.0.

__init__(container: Any, item: Any) → None[source]

Parameters:

container – The container object that the lookup was performed on.
item – The item that was used as either the key or index of container for the lookup.

container: The container object that the lookup was performed on.

item: The item that was used as either the key or index of container for the lookup.

exception MappingAttributeLookupDeprecation[source]

Bases: DeprecationWarning

A DeprecationWarning subclass emitted when a rule accesses an attribute on a MAPPING value via dot syntax, falling back to key-style lookup. The fallback is scheduled for removal in v6.0; migrate to mapping['key'] syntax or construct the Context with mapping_attribute_lookup=False to opt out now. Filter this class via warnings to silence the notice during the transition window.

Added in version 5.0.0.

exception ObjectAttributeError(attribute_name: str, object_: Any, thing: Any = UNDEFINED, suggestion: str | None = None)[source]

Bases: AttributeResolutionError

An error raised when an attribute can not be resolved against an OBJECT schema. This is a subclass of AttributeResolutionError so existing handlers keep working, but it lets users identify schema-driven lookup failures specifically.

Added in version 5.0.0.

exception RegexSyntaxError(message: str, error: error, value: str)[source]

Bases: SyntaxError

An error raised for issues regarding the use of improper regular expression syntax.

__init__(message: str, error: error, value: str) → None[source]

Parameters:

message (str) – A text description of what error occurred.
error (re.error) – The re.error exception from which this error was triggered.
value (str) – The regular expression value which contains the syntax error which caused this exception to be raised.

error: The re.error exception from which this error was triggered.

value: The regular expression value which contains the syntax error which caused this exception to be raised.

exception RuleSyntaxError(message: str, token: Any = None)[source]

Bases: SyntaxError

An error raised for issues identified while parsing the grammar of the rule text.

__init__(message: str, token: Any = None) → None[source]

Parameters:

message (str) – A text description of what error occurred.
token – The PLY token (if available) which is related to the syntax error.

token: The PLY token (if available) which is related to the syntax error.

exception StringSyntaxError(message: str, value: str)[source]

Bases: SyntaxError

An error raised for issues regarding the use of improperly formatted string expressions.

Added in version 4.5.0.

__init__(message: str, value: str) → None[source]

Parameters:

message (str) – A text description of what error occurred.
value (str) – The string value which contains the syntax error which caused this exception to be raised.

value: The string value which contains the syntax error which caused this exception to be raised.

exception SymbolResolutionError(symbol_name: str, symbol_scope: str | None = None, thing: Any = UNDEFINED, suggestion: str | None = None)[source]

Bases: EvaluationError

An error raised when a symbol name is not able to be resolved to a value.

__init__(symbol_name: str, symbol_scope: str | None = None, thing: Any = UNDEFINED, suggestion: str | None = None) → None[source]

Parameters:

symbol_name (str) – The name of the symbol that can not be resolved.
symbol_scope (str) – The scope of where the symbol should be valid for resolution.
thing – The root-object that was used to resolve the symbol.
suggestion (str) – An optional suggestion for a valid symbol name.

Changed in version 2.0.0: Added the thing parameter.

Changed in version 3.2.0: Added the suggestion parameter.

suggestion: An optional suggestion for a valid symbol name.

symbol_name: The name of the symbol that can not be resolved.

symbol_scope: The scope of where the symbol should be valid for resolution.

thing: The root-object that was used to resolve the symbol.

exception SymbolTypeError(symbol_name: str, is_value: Any, is_type: _DataTypeDef, expected_type: _DataTypeDef)[source]

Bases: EvaluationError

An error raised when a symbol with type information is resolved to a Python value that is not of that type.

__init__(symbol_name: str, is_value: Any, is_type: _DataTypeDef, expected_type: _DataTypeDef) → None[source]

Parameters:

symbol_name (str) – The name of the symbol that is of an incompatible type.
is_value – The native Python value of the incompatible symbol.
is_type – The rule-engine type of the incompatible symbol.
expected_type – The rule-engine type that was expected for this symbol.

expected_type: The rule-engine type that was expected for this symbol.

is_type: The rule-engine type of the incompatible symbol.

is_value: The native Python value of the incompatible symbol.

symbol_name: The name of the symbol that is of an incompatible type.

exception SyntaxError(message: str = '')[source]

Bases: EngineError

A base error for syntax related issues.

exception TimedeltaSyntaxError(message: str, value: str)[source]

Bases: SyntaxError

An error raised for issues regarding the use of improperly formatted timedelta expressions.

Added in version 3.5.0.

__init__(message: str, value: str) → None[source]

Parameters:

message (str) – A text description of what error occurred.
value (str) – The timedelta value which contains the syntax error which caused this exception to be raised.

value: The timedelta value which contains the syntax error which caused this exception to be raised.

Exception Hierarchy

The class hierarchy for Rule Engine exceptions is:

EngineError
 +-- EvaluationError
      +-- ArithmeticError
      +-- AttributeResolutionError
           +-- ObjectAttributeError
      +-- AttributeTypeError
      +-- FunctionCallError
      +-- LookupError
      +-- SymbolResolutionError
      +-- SymbolTypeError
 +-- SyntaxError
      +-- BytesSyntaxError
      +-- DatetimeSyntaxError
      +-- FloatSyntaxError
      +-- RegexSyntaxError
      +-- RuleSyntaxError
      +-- StringSyntaxError
      +-- TimedeltaSyntaxError
DeprecationWarning
 +-- MappingAttributeLookupDeprecation

errors

Data

Exceptions

Exception Hierarchy

`errors`