# orm/evaluator.py
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# Copyright (C) 2005-2023 the SQLAlchemy authors and contributors
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# <see AUTHORS file>
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#
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# This module is part of SQLAlchemy and is released under
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# the MIT License: https://www.opensource.org/licenses/mit-license.php
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# mypy: ignore-errors
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"""Evaluation functions used **INTERNALLY** by ORM DML use cases.
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This module is **private, for internal use by SQLAlchemy**.
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.. versionchanged:: 2.0.4 renamed ``EvaluatorCompiler`` to
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``_EvaluatorCompiler``.
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"""
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from __future__ import annotations
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from typing import Type
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from . import exc as orm_exc
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from .base import LoaderCallableStatus
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from .base import PassiveFlag
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from .. import exc
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from .. import inspect
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from ..sql import and_
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from ..sql import operators
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from ..sql.sqltypes import Integer
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from ..sql.sqltypes import Numeric
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from ..util import warn_deprecated
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class UnevaluatableError(exc.InvalidRequestError):
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pass
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class _NoObject(operators.ColumnOperators):
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def operate(self, *arg, **kw):
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return None
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def reverse_operate(self, *arg, **kw):
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return None
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class _ExpiredObject(operators.ColumnOperators):
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def operate(self, *arg, **kw):
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return self
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def reverse_operate(self, *arg, **kw):
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return self
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_NO_OBJECT = _NoObject()
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_EXPIRED_OBJECT = _ExpiredObject()
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class _EvaluatorCompiler:
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def __init__(self, target_cls=None):
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self.target_cls = target_cls
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def process(self, clause, *clauses):
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if clauses:
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clause = and_(clause, *clauses)
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meth = getattr(self, f"visit_{clause.__visit_name__}", None)
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if not meth:
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raise UnevaluatableError(
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f"Cannot evaluate {type(clause).__name__}"
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)
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return meth(clause)
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def visit_grouping(self, clause):
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return self.process(clause.element)
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def visit_null(self, clause):
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return lambda obj: None
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def visit_false(self, clause):
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return lambda obj: False
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def visit_true(self, clause):
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return lambda obj: True
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def visit_column(self, clause):
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try:
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parentmapper = clause._annotations["parentmapper"]
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except KeyError as ke:
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raise UnevaluatableError(
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f"Cannot evaluate column: {clause}"
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) from ke
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if self.target_cls and not issubclass(
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self.target_cls, parentmapper.class_
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):
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raise UnevaluatableError(
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"Can't evaluate criteria against "
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f"alternate class {parentmapper.class_}"
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)
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parentmapper._check_configure()
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# we'd like to use "proxy_key" annotation to get the "key", however
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# in relationship primaryjoin cases proxy_key is sometimes deannotated
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# and sometimes apparently not present in the first place (?).
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# While I can stop it from being deannotated (though need to see if
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# this breaks other things), not sure right now about cases where it's
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# not there in the first place. can fix at some later point.
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# key = clause._annotations["proxy_key"]
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# for now, use the old way
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try:
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key = parentmapper._columntoproperty[clause].key
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except orm_exc.UnmappedColumnError as err:
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raise UnevaluatableError(
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f"Cannot evaluate expression: {err}"
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) from err
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# note this used to fall back to a simple `getattr(obj, key)` evaluator
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# if impl was None; as of #8656, we ensure mappers are configured
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# so that impl is available
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impl = parentmapper.class_manager[key].impl
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def get_corresponding_attr(obj):
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if obj is None:
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return _NO_OBJECT
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state = inspect(obj)
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dict_ = state.dict
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value = impl.get(
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state, dict_, passive=PassiveFlag.PASSIVE_NO_FETCH
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)
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if value is LoaderCallableStatus.PASSIVE_NO_RESULT:
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return _EXPIRED_OBJECT
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return value
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return get_corresponding_attr
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def visit_tuple(self, clause):
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return self.visit_clauselist(clause)
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def visit_expression_clauselist(self, clause):
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return self.visit_clauselist(clause)
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def visit_clauselist(self, clause):
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evaluators = [self.process(clause) for clause in clause.clauses]
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dispatch = (
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f"visit_{clause.operator.__name__.rstrip('_')}_clauselist_op"
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)
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meth = getattr(self, dispatch, None)
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if meth:
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return meth(clause.operator, evaluators, clause)
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else:
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raise UnevaluatableError(
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f"Cannot evaluate clauselist with operator {clause.operator}"
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)
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def visit_binary(self, clause):
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eval_left = self.process(clause.left)
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eval_right = self.process(clause.right)
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dispatch = f"visit_{clause.operator.__name__.rstrip('_')}_binary_op"
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meth = getattr(self, dispatch, None)
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if meth:
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return meth(clause.operator, eval_left, eval_right, clause)
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else:
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raise UnevaluatableError(
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f"Cannot evaluate {type(clause).__name__} with "
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f"operator {clause.operator}"
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)
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def visit_or_clauselist_op(self, operator, evaluators, clause):
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def evaluate(obj):
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has_null = False
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for sub_evaluate in evaluators:
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value = sub_evaluate(obj)
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if value is _EXPIRED_OBJECT:
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return _EXPIRED_OBJECT
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elif value:
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return True
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has_null = has_null or value is None
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if has_null:
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return None
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return False
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return evaluate
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def visit_and_clauselist_op(self, operator, evaluators, clause):
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def evaluate(obj):
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for sub_evaluate in evaluators:
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value = sub_evaluate(obj)
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if value is _EXPIRED_OBJECT:
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return _EXPIRED_OBJECT
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if not value:
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if value is None or value is _NO_OBJECT:
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return None
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return False
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return True
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return evaluate
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def visit_comma_op_clauselist_op(self, operator, evaluators, clause):
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def evaluate(obj):
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values = []
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for sub_evaluate in evaluators:
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value = sub_evaluate(obj)
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if value is _EXPIRED_OBJECT:
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return _EXPIRED_OBJECT
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elif value is None or value is _NO_OBJECT:
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return None
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values.append(value)
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return tuple(values)
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return evaluate
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def visit_custom_op_binary_op(
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self, operator, eval_left, eval_right, clause
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):
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if operator.python_impl:
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return self._straight_evaluate(
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operator, eval_left, eval_right, clause
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)
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else:
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raise UnevaluatableError(
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f"Custom operator {operator.opstring!r} can't be evaluated "
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"in Python unless it specifies a callable using "
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"`.python_impl`."
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)
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def visit_is_binary_op(self, operator, eval_left, eval_right, clause):
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def evaluate(obj):
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left_val = eval_left(obj)
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right_val = eval_right(obj)
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if left_val is _EXPIRED_OBJECT or right_val is _EXPIRED_OBJECT:
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return _EXPIRED_OBJECT
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return left_val == right_val
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return evaluate
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def visit_is_not_binary_op(self, operator, eval_left, eval_right, clause):
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def evaluate(obj):
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left_val = eval_left(obj)
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right_val = eval_right(obj)
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if left_val is _EXPIRED_OBJECT or right_val is _EXPIRED_OBJECT:
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return _EXPIRED_OBJECT
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return left_val != right_val
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return evaluate
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def _straight_evaluate(self, operator, eval_left, eval_right, clause):
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def evaluate(obj):
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left_val = eval_left(obj)
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right_val = eval_right(obj)
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if left_val is _EXPIRED_OBJECT or right_val is _EXPIRED_OBJECT:
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return _EXPIRED_OBJECT
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elif left_val is None or right_val is None:
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return None
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return operator(eval_left(obj), eval_right(obj))
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return evaluate
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def _straight_evaluate_numeric_only(
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self, operator, eval_left, eval_right, clause
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):
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if clause.left.type._type_affinity not in (
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Numeric,
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Integer,
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) or clause.right.type._type_affinity not in (Numeric, Integer):
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raise UnevaluatableError(
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f'Cannot evaluate math operator "{operator.__name__}" for '
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f"datatypes {clause.left.type}, {clause.right.type}"
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)
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return self._straight_evaluate(operator, eval_left, eval_right, clause)
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visit_add_binary_op = _straight_evaluate_numeric_only
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visit_mul_binary_op = _straight_evaluate_numeric_only
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visit_sub_binary_op = _straight_evaluate_numeric_only
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visit_mod_binary_op = _straight_evaluate_numeric_only
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visit_truediv_binary_op = _straight_evaluate_numeric_only
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visit_lt_binary_op = _straight_evaluate
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visit_le_binary_op = _straight_evaluate
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visit_ne_binary_op = _straight_evaluate
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visit_gt_binary_op = _straight_evaluate
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visit_ge_binary_op = _straight_evaluate
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visit_eq_binary_op = _straight_evaluate
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def visit_in_op_binary_op(self, operator, eval_left, eval_right, clause):
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return self._straight_evaluate(
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lambda a, b: a in b if a is not _NO_OBJECT else None,
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eval_left,
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eval_right,
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clause,
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)
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def visit_not_in_op_binary_op(
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self, operator, eval_left, eval_right, clause
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):
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return self._straight_evaluate(
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lambda a, b: a not in b if a is not _NO_OBJECT else None,
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eval_left,
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eval_right,
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clause,
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)
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def visit_concat_op_binary_op(
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self, operator, eval_left, eval_right, clause
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):
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return self._straight_evaluate(
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lambda a, b: a + b, eval_left, eval_right, clause
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)
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def visit_startswith_op_binary_op(
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self, operator, eval_left, eval_right, clause
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):
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return self._straight_evaluate(
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lambda a, b: a.startswith(b), eval_left, eval_right, clause
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)
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def visit_endswith_op_binary_op(
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self, operator, eval_left, eval_right, clause
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):
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return self._straight_evaluate(
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lambda a, b: a.endswith(b), eval_left, eval_right, clause
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)
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def visit_unary(self, clause):
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eval_inner = self.process(clause.element)
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if clause.operator is operators.inv:
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def evaluate(obj):
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value = eval_inner(obj)
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if value is _EXPIRED_OBJECT:
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return _EXPIRED_OBJECT
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elif value is None:
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return None
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return not value
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return evaluate
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raise UnevaluatableError(
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f"Cannot evaluate {type(clause).__name__} "
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f"with operator {clause.operator}"
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)
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def visit_bindparam(self, clause):
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if clause.callable:
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val = clause.callable()
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else:
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val = clause.value
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return lambda obj: val
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def __getattr__(name: str) -> Type[_EvaluatorCompiler]:
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if name == "EvaluatorCompiler":
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warn_deprecated(
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"Direct use of 'EvaluatorCompiler' is not supported, and this "
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"name will be removed in a future release. "
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"'_EvaluatorCompiler' is for internal use only",
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"2.0",
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)
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return _EvaluatorCompiler
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else:
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raise AttributeError(f"module {__name__!r} has no attribute {name!r}")
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