#!/usr/bin/env python3
# -*- coding: utf-8 -*-
#
# rule_engine/errors.py
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
# * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# * Redistributions in binary form must reproduce the above
# copyright notice, this list of conditions and the following disclaimer
# in the documentation and/or other materials provided with the
# distribution.
# * Neither the name of the project nor the names of its
# contributors may be used to endorse or promote products derived from
# this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
class _UNDEFINED(object):
def __bool__(self):
return False
__name__ = 'UNDEFINED'
__nonzero__ = __bool__
def __repr__(self):
return self.__name__
UNDEFINED = _UNDEFINED()
"""
A sentinel value to specify that something is undefined. When evaluated, the value is falsy.
.. versionadded:: 2.0.0
"""
[docs]
class EngineError(Exception):
"""The base exception class from which other exceptions within this package inherit."""
[docs]
def __init__(self, message=''):
"""
:param str message: A text description of what error occurred.
"""
self.message = message
"""A text description of what error occurred."""
def __repr__(self):
return "<{} message={!r} >".format(self.__class__.__name__, self.message)
[docs]
class EvaluationError(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.
"""
pass
[docs]
class SyntaxError(EngineError):
"""A base error for syntax related issues."""
[docs]
class DatetimeSyntaxError(SyntaxError):
"""An error raised for issues regarding the use of improperly formatted datetime expressions."""
[docs]
def __init__(self, message, value):
"""
:param str message: A text description of what error occurred.
:param str value: The datetime value which contains the syntax error which caused this exception to be raised.
"""
super(DatetimeSyntaxError, self).__init__(message)
self.value = value
"""The datetime value which contains the syntax error which caused this exception to be raised."""
[docs]
class FloatSyntaxError(SyntaxError):
"""
An error raised for issues regarding the use of improperly formatted float expressions.
.. versionadded:: 4.0.0
"""
[docs]
def __init__(self, message, value):
"""
:param str message: A text description of what error occurred.
:param str value: The float value which contains the syntax error which caused this exception to be raised.
"""
super(FloatSyntaxError, self).__init__(message)
self.value = value
"""The float value which contains the syntax error which caused this exception to be raised."""
[docs]
class TimedeltaSyntaxError(SyntaxError):
"""
An error raised for issues regarding the use of improperly formatted timedelta expressions.
.. versionadded:: 3.5.0
"""
[docs]
def __init__(self, message, value):
"""
:param str message: A text description of what error occurred.
:param str value: The timedelta value which contains the syntax error which caused this exception to be raised.
"""
super(TimedeltaSyntaxError, self).__init__(message)
self.value = value
"""The timedelta value which contains the syntax error which caused this exception to be raised."""
[docs]
class RegexSyntaxError(SyntaxError):
"""An error raised for issues regarding the use of improper regular expression syntax."""
[docs]
def __init__(self, message, error, value):
"""
:param str message: A text description of what error occurred.
:param error: The :py:exc:`re.error` exception from which this error was triggered.
:type error: :py:exc:`re.error`
:param str value: The regular expression value which contains the syntax error which caused this exception to be
raised.
"""
super(RegexSyntaxError, self).__init__(message)
self.error = error
"""The :py:exc:`re.error` exception from which this error was triggered."""
self.value = value
"""The regular expression value which contains the syntax error which caused this exception to be raised."""
[docs]
class RuleSyntaxError(SyntaxError):
"""An error raised for issues identified while parsing the grammar of the rule text."""
[docs]
def __init__(self, message, token=None):
"""
:param str message: A text description of what error occurred.
:param token: The PLY token (if available) which is related to the syntax error.
"""
if token is None:
position = 'EOF'
else:
position = "line {0}:{1}".format(token.lineno, token.lexpos)
message = message + ' at: ' + position
super(RuleSyntaxError, self).__init__(message)
self.token = token
"""The PLY token (if available) which is related to the syntax error."""
[docs]
class AttributeResolutionError(EvaluationError):
"""
An error raised with an attribute can not be resolved to a value.
.. versionadded:: 2.0.0
"""
[docs]
def __init__(self, attribute_name, object_, thing=UNDEFINED, suggestion=None):
"""
:param str attribute_name: The name of the symbol that can not be resolved.
:param object_: The value that *attribute_name* was used as an attribute for.
:param thing: The root-object that was used to resolve *object*.
:param str suggestion: An optional suggestion for a valid attribute name.
.. versionchanged:: 3.2.0
Added the *suggestion* parameter.
"""
self.attribute_name = attribute_name
"""The name of the symbol that can not be resolved."""
self.object = object_
"""The value that *attribute_name* was used as an attribute for."""
self.thing = thing
"""The root-object that was used to resolve *object*."""
self.suggestion = suggestion
"""An optional suggestion for a valid attribute name."""
super(AttributeResolutionError, self).__init__("unknown attribute: {0!r}".format(attribute_name))
def __repr__(self):
return "<{} message={!r} suggestion={!r} >".format(self.__class__.__name__, self.message, self.suggestion)
[docs]
class AttributeTypeError(EvaluationError):
"""
An error raised when an attribute with type information is resolved to a Python value that is not of that type.
"""
[docs]
def __init__(self, attribute_name, object_type, is_value, is_type, expected_type):
"""
:param str attribute_name: The name of the symbol that can not be resolved.
:param object_type: The value that *attribute_name* was used as an attribute for.
:param is_value: The native Python value of the incompatible attribute.
:param is_type: The :py:class:`rule-engine type<rule_engine.ast.DataType>` of the incompatible attribute.
:param expected_type: The :py:class:`rule-engine type<rule_engine.ast.DataType>` that was expected for this
attribute.
"""
self.attribute_name = attribute_name
"""The name of the attribute that is of an incompatible type."""
self.object_type = object_type
"""The object on which the attribute was resolved."""
self.is_value = is_value
"""The native Python value of the incompatible attribute."""
self.is_type = is_type
"""The :py:class:`rule-engine type<rule_engine.ast.DataType>` of the incompatible attribute."""
self.expected_type = expected_type
"""The :py:class:`rule-engine type<rule_engine.ast.DataType>` that was expected for this attribute."""
message = "attribute {0!r} resolved to incorrect datatype (is: {1}, expected: {2})".format(
attribute_name,
is_type.name,
expected_type.name
)
super(AttributeTypeError, self).__init__(message)
[docs]
class LookupError(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 :py:exc:`IndexError` and :py:exc:`KeyError` exceptions.
.. versionadded:: 2.4.0
"""
[docs]
def __init__(self, container, item):
"""
:param container: The container object that the lookup was performed on.
:param item: The item that was used as either the key or index of *container* for the lookup.
"""
self.container = container
"""The container object that the lookup was performed on."""
self.item = item
"""The item that was used as either the key or index of *container* for the lookup."""
super(LookupError, self).__init__('lookup operation failed')
[docs]
class SymbolResolutionError(EvaluationError):
"""An error raised when a symbol name is not able to be resolved to a value."""
[docs]
def __init__(self, symbol_name, symbol_scope=None, thing=UNDEFINED, suggestion=None):
"""
:param str symbol_name: The name of the symbol that can not be resolved.
:param str symbol_scope: The scope of where the symbol should be valid for resolution.
:param thing: The root-object that was used to resolve the symbol.
:param str suggestion: An optional suggestion for a valid symbol name.
.. versionchanged:: 2.0.0
Added the *thing* parameter.
.. versionchanged:: 3.2.0
Added the *suggestion* parameter.
"""
self.symbol_name = symbol_name
"""The name of the symbol that can not be resolved."""
self.symbol_scope = symbol_scope
"""The scope of where the symbol should be valid for resolution."""
self.thing = thing
"""The root-object that was used to resolve the symbol."""
self.suggestion = suggestion
"""An optional suggestion for a valid symbol name."""
super(SymbolResolutionError, self).__init__("unknown symbol: {0!r}".format(symbol_name))
def __repr__(self):
return "<{} message={!r} suggestion={!r} >".format(self.__class__.__name__, self.message, self.suggestion)
[docs]
class SymbolTypeError(EvaluationError):
"""An error raised when a symbol with type information is resolved to a Python value that is not of that type."""
[docs]
def __init__(self, symbol_name, is_value, is_type, expected_type):
"""
:param str symbol_name: The name of the symbol that is of an incompatible type.
:param is_value: The native Python value of the incompatible symbol.
:param is_type: The :py:class:`rule-engine type<rule_engine.ast.DataType>` of the incompatible symbol.
:param expected_type: The :py:class:`rule-engine type<rule_engine.ast.DataType>` that was expected for this
symbol.
"""
self.symbol_name = symbol_name
"""The name of the symbol that is of an incompatible type."""
self.is_value = is_value
"""The native Python value of the incompatible symbol."""
self.is_type = is_type
"""The :py:class:`rule-engine type<rule_engine.ast.DataType>` of the incompatible symbol."""
self.expected_type = expected_type
"""The :py:class:`rule-engine type<rule_engine.ast.DataType>` that was expected for this symbol."""
message = "symbol {0!r} resolved to incorrect datatype (is: {1}, expected: {2})".format(
symbol_name,
is_type.name,
expected_type.name
)
super(SymbolTypeError, self).__init__(message)
[docs]
class FunctionCallError(EvaluationError):
"""
An error raised when there is an issue calling a function.
.. versionadded:: 4.0.0
"""
[docs]
def __init__(self, message, error=None, function_name=None):
super(FunctionCallError, self).__init__(message)
self.error = error
"""The exception from which this error was triggered."""
self.function_name = function_name