rdblue commented on a change in pull request #4262: URL: https://github.com/apache/iceberg/pull/4262#discussion_r827482687
########## File path: python/src/iceberg/expression/literals.py ########## @@ -0,0 +1,713 @@ +# Licensed under the Apache License, Version 2.0 (the "License"); +# you may not use this file except in compliance with the License. +# You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +# See the License for the specific language governing permissions and +# limitations under the License. +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, +# software distributed under the License is distributed on an +# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +# KIND, either express or implied. See the License for the +# specific language governing permissions and limitations +# under the License. + +import datetime +import sys +import uuid +from decimal import ROUND_HALF_UP, Decimal +from functools import singledispatch +from typing import Any + +from iceberg.types import PrimitiveType + +if sys.version_info >= (3, 8): + from functools import singledispatchmethod +else: + from singledispatch import singledispatchmethod + +import pytz + +from iceberg.types import ( + BinaryType, + BooleanType, + DateType, + DecimalType, + DoubleType, + FixedType, + FloatType, + IntegerType, + LongType, + Singleton, + StringType, + TimestampType, + TimestamptzType, + TimeType, + UUIDType, +) + +EPOCH = datetime.datetime.utcfromtimestamp(0) + +""" +Iceberg literal is wrapper class used in expressions, which return unbound predicates +It's being organized as below +Literal +|-- AboveMax +|-- BelowMin +|-- BaseLiteral + |-- StringLiteral + |-- FixedLiteral + |-- BinaryLiteral + |-- ComparableLiteral + |-- BooleanLiteral + |-- IntegerLiteral + |-- LongLiteral + |-- FloatLiteral + |-- DoubleLiteral + |-- DateLiteral + |-- TimeLiteral + |-- TimestampLiteral + |-- DecimalLiteral + |-- UUIDLiteral +""" + + +class Literal: + def to(self, type_var: PrimitiveType): + raise NotImplementedError() + + def to_byte_buffer(self): + raise NotImplementedError() + + +@singledispatch +def literal(value: Any): + """ + A generic Literal factory to construct an iceberg Literal based on python primitive data type + using dynamic overloading + + Args: + value(python primitive type): the value to be associated with literal + + Example: + from iceberg.expressions.literals import literal + >>> literal(123) + <IntegerLiteral(123)>v + """ + raise TypeError(f"Unimplemented Type Literal for value: {value}") + + [email protected] +def _(value: bool): + return BooleanLiteral(value) + + [email protected] +def _(value: int): + """ + Upgrade to long if python int is outside the JAVA_MIN_INT and JAVA_MAX_INT + """ + if value < IntegerType.min or value > IntegerType.max: + return LongLiteral(value) + return IntegerLiteral(value) + + [email protected] +def _(value: float): + """ + Upgrade to double if python float is outside the JAVA_MIN_FLOAT and JAVA_MAX_FLOAT + """ + if value < FloatType.min or value > FloatType.max: + return DoubleLiteral(value) + return FloatLiteral(value) + + [email protected] +def _(value: str): + return StringLiteral(value) + + [email protected] +def _(value: uuid.UUID): + return UUIDLiteral(value) + + [email protected] +def _(value: bytes): + return FixedLiteral(value) + + [email protected] +def _(value: bytearray): + return BinaryLiteral(value) + + [email protected] +def _(value: Decimal): + return DecimalLiteral(value) + + +class BaseLiteral(Literal): + """Base literal which has a value and can be converted between types""" + + def __init__(self, repr_string: str, value): + self._repr_string = repr_string + self.value = value + self.byte_buffer = None + + def to(self, type_var): + raise NotImplementedError() + + def __repr__(self): + return self._repr_string + + def __str__(self): + return str(self.value) + + def to_byte_buffer(self): + # TODO need byte buffer conversion + raise NotImplementedError() + + +class ComparableLiteral(BaseLiteral): + def __init__(self, repr_string: str, value): + super(ComparableLiteral, self).__init__(repr_string, value) + + def to(self, type_var): + raise NotImplementedError() + + def __eq__(self, other): + return self.value == other.value + + def __ne__(self, other): + return not self.__eq__(other) + + def __lt__(self, other): + if self.value is None: Review comment: Literal values must never be `None`, so that we never have to worry about cases where we are comparing `None`. Can you add a `TypeError` or `ValueError` in the constructor? It is important to have this invariant for the rest of the expressions codebase. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
