lidavidm commented on code in PR #94: URL: https://github.com/apache/iceberg-cpp/pull/94#discussion_r2082993421
########## src/iceberg/util/visit_type.h: ########## @@ -0,0 +1,121 @@ +/* + * 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 + +#include "iceberg/result.h" +#include "iceberg/type.h" +#include "iceberg/util/checked_cast.h" +#include "iceberg/util/unreachable.h" +#include "iceberg/util/visitor_generate.h" + +namespace iceberg { + +#define TYPE_VISIT_INLINE(TYPE_CLASS) \ + case TYPE_CLASS##Type::kTypeId: \ + return visitor->Visit( \ + iceberg::internal::checked_cast<const TYPE_CLASS##Type&>(type), \ + std::forward<ARGS>(args)...); + +/// \brief Calls `visitor` with the corresponding concrete type class +/// +/// \tparam VISITOR Visitor type that implements Visit() for all Iceberg types. +/// \tparam ARGS Additional arguments, if any, will be passed to the Visit function after +/// the `type` argument +/// \return Status +/// +/// A visitor is a type that implements specialized logic for each Iceberg type. +/// Example usage: +/// +/// ``` +/// class ExampleVisitor { +/// Status Visit(const IntType& type) { ... } +/// Status Visit(const LongType& type) { ... } +/// ... +/// } +/// ExampleVisitor visitor; +/// VisitTypeInline(some_type, &visitor); +/// ``` + +template <typename VISITOR, typename... ARGS> +inline Status VisitTypeInline(const Type& type, VISITOR* visitor, ARGS&&... args) { + switch (type.type_id()) { + ICEBERG_GENERATE_FOR_ALL_TYPES(TYPE_VISIT_INLINE); + default: + break; + } + return NotImplemented("Type not implemented"); +} + +#undef TYPE_VISIT_INLINE + +#define TYPE_VISIT_INLINE(TYPE_CLASS) \ + case TYPE_CLASS##Type::kTypeId: \ + return std::forward<VISITOR>(visitor)( \ + internal::checked_cast<const TYPE_CLASS##Type&>(type), \ + std::forward<ARGS>(args)...); + +/// \brief Call `visitor` with the corresponding concrete type class +/// \tparam ARGS Additional arguments, if any, will be passed to the Visit function after +/// the `type` argument +/// +/// Unlike VisitTypeInline which calls `visitor.Visit`, here `visitor` +/// itself is called. +/// `visitor` must support a `const Type&` argument as a fallback, +/// in addition to concrete type classes. +/// +/// The intent is for this to be called on a generic lambda +/// that may internally use `if constexpr` or similar constructs. +template <typename VISITOR, typename... ARGS> +inline auto VisitType(const Type& type, VISITOR&& visitor, ARGS&&... args) + -> decltype(std::forward<VISITOR>(visitor)(type, args...)) { + switch (type.type_id()) { + ICEBERG_GENERATE_FOR_ALL_TYPES(TYPE_VISIT_INLINE); + default: + internal::Unreachable("Type not implemented"); Review Comment: The docstring says a fallback is called but the body aborts in the default case? -- 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
