wgtmac commented on code in PR #58: URL: https://github.com/apache/iceberg-cpp/pull/58#discussion_r2025884055
########## src/iceberg/expression.h: ########## @@ -0,0 +1,101 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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. + */ + +#pragma once + +/// \file iceberg/expression.h +/// Boolean expression tree for Iceberg table operations. + +#include <string> + +#include "iceberg/error.h" +#include "iceberg/expected.h" +#include "iceberg/iceberg_export.h" + +namespace iceberg { + +/// \brief Represents a boolean expression tree. +class ICEBERG_EXPORT Expression { + public: + /// Operation types for expressions + enum class Operation { + kTrue, + kFalse, + kIsNull, + kNotNull, + kIsNan, + kNotNan, + kLt, + kLtEq, + kGt, + kGtEq, + kEq, + kNotEq, + kIn, + kNotIn, + kNot, + kAnd, + kOr, + kStartsWith, + kNotStartsWith, + kCount, + kCountStar, + kMax, + kMin + }; + + virtual ~Expression() = default; + + /// \brief Returns the operation for an expression node. + [[nodiscard]] virtual Operation Op() const = 0; + + /// \brief Returns the negation of this expression, equivalent to not(this). + [[nodiscard]] virtual expected<std::shared_ptr<Expression>, Error> Negate() const { + return unexpected<Error>( + {ErrorKind::kInvalidExpression, "This expression cannot be negated"}); + } + + /// \brief Returns whether this expression will accept the same values as another. + /// + /// If this returns true, the expressions are guaranteed to return the same evaluation + /// for the same input. However, if this returns false the expressions may return the + /// same evaluation for the same input. That is, expressions may be equivalent even if + /// this returns false. + /// + /// For best results, rewrite not and bind expressions before calling this method. + /// + /// \param other another expression + /// \return true if the expressions are equivalent + [[nodiscard]] virtual bool IsEquivalentTo(const Expression& other) const { + // only bound predicates can be equivalent + return false; + } + + /// \brief Convert operation string to enum + static expected<Operation, Error> FromString(const std::string& operation_type); Review Comment: ```suggestion static expected<Operation, Error> FromString(std::string_view op); ``` Use string_view when possible. -- 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: issues-unsubscr...@iceberg.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@iceberg.apache.org For additional commands, e-mail: issues-h...@iceberg.apache.org
