samredai commented on a change in pull request #4262: URL: https://github.com/apache/iceberg/pull/4262#discussion_r836855070
########## File path: python/src/iceberg/expression/literals.py ########## @@ -0,0 +1,502 @@ +# 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 struct +import sys +import uuid +from abc import ABC, abstractmethod +from decimal import ROUND_HALF_UP, Decimal +from functools import singledispatch +from typing import Generic, Optional, TypeVar, Union + +if sys.version_info >= (3, 8): + from functools import singledispatchmethod # pragma: no cover +else: + from singledispatch import singledispatchmethod # pragma: no cover + +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) +T = TypeVar("T") + + +class Literal(Generic[T], ABC): + """Literal which has a value and can be converted between types""" + + def __init__(self, value: T): + if value is None: + raise TypeError(f"Invalid literal value: {value}") + self._value = value + + @property + def value(self) -> T: + return self._value + + @abstractmethod + def to(self, type_var): + ... # pragma: no cover + + def __repr__(self): + return f"{type(self).__name__}({self.value})" + + def __str__(self): + return str(self.value) + + def __eq__(self, other): + return self.value == other.value + + def __ne__(self, other): + return not self.__eq__(other) + + def __lt__(self, other): + return self.value < other.value + + def __gt__(self, other): + return self.value > other.value + + def __le__(self, other): + return self.value <= other.value + + def __ge__(self, other): + return self.value >= other.value + + +@singledispatch +def literal(value) -> Literal: + """ + 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) + """ + raise TypeError(f"Unimplemented Type Literal for value: {str(value)}") + + [email protected](bool) +def _(value: bool) -> Literal[bool]: + return BooleanLiteral(value) + + [email protected](int) +def _(value: int) -> Literal[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](float) +def _(value: float) -> Literal[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](str) +def _(value: str) -> Literal[str]: + return StringLiteral(value) + + [email protected](uuid.UUID) +def _(value: uuid.UUID) -> Literal[uuid.UUID]: + return UUIDLiteral(value) + + [email protected](bytes) +def _(value: bytes) -> Literal[bytes]: + return FixedLiteral(value) + + [email protected](bytearray) +def _(value: bytearray) -> Literal[bytes]: + return BinaryLiteral(value) + + [email protected](Decimal) +def _(value: Decimal) -> Literal[Decimal]: + return DecimalLiteral(value) + + +class AboveMax(Literal[None], Singleton): + def __init__(self): + pass + + def value(self): + raise ValueError("AboveMax has no value") + + def to(self, type_var): + raise TypeError("Cannot change the type of AboveMax") + + def __repr__(self): + return "AboveMax()" + + def __str__(self): + return "AboveMax" + + +class BelowMin(Literal[None], Singleton): + def __init__(self): + pass + + def value(self): + raise ValueError("BelowMin has no value") + + def to(self, type_var): + raise TypeError("Cannot change the type of BelowMin") + + def __repr__(self): + return "BelowMin()" + + def __str__(self): + return "BelowMin" + + +class BooleanLiteral(Literal[bool]): + def __init__(self, value): + self._value = value Review comment: +1 I think removing all of the `__init__` methods and letting it fall back the super class is the way to go. -- This is an automated message from the Apache Git Service. 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