samredai commented on a change in pull request #4262: URL: https://github.com/apache/iceberg/pull/4262#discussion_r821105290
########## File path: python/src/iceberg/expression/literals.py ########## @@ -0,0 +1,742 @@ +# 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 + +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, +) + +JAVA_MAX_INT = 2147483647 +JAVA_MIN_INT = -2147483648 +JAVA_MAX_FLOAT = 3.4028235e38 +JAVA_MIN_FLOAT = -3.4028235e38 +EPOCH = datetime.datetime.utcfromtimestamp(0) +EPOCH_DAY = EPOCH.date() + +""" +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): + raise NotImplementedError() + + def to_byte_buffer(self): + raise NotImplementedError() + + +@singledispatch +def of(value): + """ + 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: + import iceberg.expressions.literals + >>> iceberg.expressions.literals.of(1) + IntegerLiteral(1) + """ + raise TypeError(f"Unimplemented Type Literal for value: {value}") + + [email protected](bool) +def _of(value): + return BooleanLiteral(value) + + [email protected](int) +def _(value): + """ + Upgrade to long if python int is outside the JAVA_MIN_INT and JAVA_MAX_INT + """ + if value < JAVA_MIN_INT or value > JAVA_MAX_INT: + return LongLiteral(value) + return IntegerLiteral(value) + + [email protected](float) +def _(value): + """ + Upgrade to double if python float is outside the JAVA_MIN_FLOAT and JAVA_MAX_FLOAT + """ + if value < JAVA_MIN_FLOAT or value > JAVA_MAX_FLOAT: + return DoubleLiteral(value) + return FloatLiteral(value) + + [email protected](str) +def _(value): + return StringLiteral(value) + + [email protected](uuid.UUID) +def _(value): + return UUIDLiteral(value) + + [email protected](bytes) +def _(value): + return FixedLiteral(value) + + [email protected](bytearray) +def _(value): + return BinaryLiteral(value) + + [email protected](Decimal) +def _(value): + 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 __eq__(self, other): + if id(self) == id(other): + return True + elif other is None or not isinstance(other, BaseLiteral): + return False + + return self.value == other.value + + def __ne__(self, other): + return not self.__eq__(other) + + def __repr__(self): + return self._repr_string + + def __str__(self): + return str(self.value) + + def to_byte_buffer(self): + if self.byte_buffer is None: + # TODO need byte buffer conversion + raise NotImplementedError() + + return self.byte_buffer + + +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: + return True + + if other is None or other.value is None: + return False + + return self.value < other.value + + def __gt__(self, other): + if self.value is None: + return False + + if other is None or other.value is None: + return True + + return self.value > other.value + + def __le__(self, other): + if self.value is None: + return True + + if other is None or other.value is None: + return False + + return self.value <= other.value + + def __ge__(self, other): + if self.value is None: + return False + + if other is None or other.value is None: + return True + + return self.value >= other.value + + +class AboveMax(Literal, Singleton): + _instance = None + + def __init__(self): + self._initialized = True + super(AboveMax, self).__init__() + + def value(self): + raise RuntimeError("AboveMax has no value") + + def to(self, type_var): + raise RuntimeError("Cannot change the type of AboveMax") + + def __str__(self): + return "aboveMax" + + +class BelowMin(Literal, Singleton): + _instance = None + + def __init__(self): + self._initialized = True + super(BelowMin, self).__init__() + + def value(self): + raise RuntimeError("BelowMin has no value") + + def to(self, type_var): + raise RuntimeError("Cannot change the type of BelowMin") + + def __str__(self): + return "belowMin" + + +class BooleanLiteral(ComparableLiteral): + def __init__(self, value): + super(BooleanLiteral, self).__init__(f"BooleanLiteral({value})", value) + + @singledispatchmethod + def to(self, type_var): + return None + + @to.register(BooleanType) + def boolean_literal_to(self, type_var): Review comment: Just for consistency I would make name this `_` as well. -- This is an automated message from the Apache Git Service. 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