Backport of some concepts from util to C++17

benchmark/BenchmarkExamples.cpp

@@ -53,14 +53,14 @@ class ConfigOptions : public BenchmarkInterface {
 
     manager.addOption("date", "The current date.", &dateString_, "22.3.2023"s);
 
-    auto numSigns =
-        manager.addOption("num-signs", "The number of street signs.",
-                          &numberOfStreetSigns_, 10000);
-    manager.addValidator([](const int& num) { return num >= 0; },
-                         "The number of street signs must be at least 0!",
-                         "Negative numbers, or floating point numbers, are not "
-                         "allowed for the configuration option \"num-signs\".",
-                         numSigns);
+    // auto numSigns =
+    //     manager.addOption("num-signs", "The number of street signs.",
+    //                       &numberOfStreetSigns_, 10000);
+    // manager.addValidator([](const int& num) -> bool { return num >= 0; },
+    //                      "The number of street signs must be at least 0!",
+    //                      "Negative numbers, or floating point numbers, are not "
+    //                      "allowed for the configuration option \"num-signs\".",
+    //                      numSigns);
 
     manager.addOption("coin-flip-try", "The number of successful coin flips.",
                       &wonOnTryX_, {false, false, false, false, false});

benchmark/infrastructure/BenchmarkMeasurementContainer.h

@@ -227,8 +227,8 @@ class ResultTable : public BenchmarkMetadataGetter {
 
   @param row, column Which table entry to read. Starts with `(0,0)`.
   */
-  template <ad_utility::SameAsAnyTypeIn<EntryType> T>
-  T getEntry(const size_t row, const size_t column) const {
+  CPP_template(typename T)(requires ad_utility::SameAsAnyTypeIn<T, EntryType>) T
+      getEntry(const size_t row, const size_t column) const {
     AD_CONTRACT_CHECK(row < numRows() && column < numColumns());
     static_assert(!ad_utility::isSimilar<T, std::monostate>);
 

benchmark/infrastructure/BenchmarkToJson.cpp

@@ -31,12 +31,12 @@ provided translation function for the vector entries.
 @tparam TranslationFunction Has to be a function, that takes `VectorType`
 and returns a `nlohmann:json` object.
 */
-template <typename VectorType, ad_utility::InvocableWithExactReturnType<
-                                   nlohmann::ordered_json, VectorType>
-                                   TranslationFunction>
-static nlohmann::json transformIntoJsonArray(
-    const std::vector<VectorType>& vec,
-    TranslationFunction translationFunction) {
+CPP_template(typename VectorType, typename TranslationFunction)(
+    requires ad_utility::InvocableWithExactReturnType<
+        TranslationFunction, nlohmann::ordered_json,
+        VectorType>) static nlohmann::json
+    transformIntoJsonArray(const std::vector<VectorType>& vec,
+                           TranslationFunction translationFunction) {
   /*
   Without explicit instantiation, `nlohmann::nlohmann::ordered_json` is not
   guaranteed, to always interpret a `push_back` correctly. For instance,

src/engine/idTable/IdTableRow.h

@@ -381,8 +381,10 @@ class RowReference
   // The `cbegin` and `cend` functions are implicitly inherited from `Base`.
 
   // __________________________________________________________________________
-  template <ad_utility::SimilarTo<RowReference> R>
-  friend void swap(R&& a, R&& b) requires(!isConst) {
+  CPP_template(typename R)(
+      requires ad_utility::SimilarTo<RowReference, R>) friend void swap(R&& a,
+                                                                        R&& b)
+      requires(!isConst) {
     return Base::swapImpl(AD_FWD(a), AD_FWD(b));
   }
 

src/global/Pattern.h

@@ -13,6 +13,7 @@
 #include <vector>
 
 #include "global/Id.h"
+#include "backports/concepts.h"
 #include "util/ExceptionHandling.h"
 #include "util/File.h"
 #include "util/Generator.h"
@@ -71,6 +72,27 @@ struct CompactStringVectorWriter;
 
 }
 
+#ifdef QLEVER_CPP_17
+template <typename T, typename = void>
+struct IsIteratorOfIterator : std::false_type {};
+
+template <typename T>
+struct IsIteratorOfIterator<
+    T, std::void_t<decltype(*(T::iterator::value_type::begin()))>>
+    : std::true_type {};
+
+template <typename T, typename DataType>
+CPP_concept IteratorOfIterator = 
+    (IsIteratorOfIterator<T>::value &&
+     ad_utility::SimilarTo<decltype(*(T::iterator::value_type::begin())),
+                           DataType>);
+#else
+template <typename T, typename DataType>
+concept IteratorOfIterator = requires(T t) {
+  { *(t.begin()->begin()) } -> ad_utility::SimilarTo<DataType>;
+};
+#endif
+
 /**
  * @brief Stores a list of variable length data of a single type (e.g.
  *        c-style strings). The data is stored in a single contiguous block
@@ -102,10 +124,8 @@ class CompactVectorOfStrings {
    * @brief Fills this CompactVectorOfStrings with input.
    * @param The input from which to build the vector.
    */
-  template <typename T>
-  requires requires(T t) {
-    { *(t.begin()->begin()) } -> ad_utility::SimilarTo<data_type>;
-  } void build(const T& input) {
+  CPP_template(typename T)(
+      requires IteratorOfIterator<T, data_type>) void build(const T& input) {
     // Also make room for the end offset of the last element.
     _offsets.reserve(input.size() + 1);
     size_t dataSize = 0;

src/index/StringSortComparator.h

@@ -51,8 +51,8 @@ class LocaleManager {
   using U8String = std::basic_string<uint8_t>;
   using U8StringView = std::basic_string_view<uint8_t>;
 
-  template <ad_utility::SimilarToAny<U8String, U8StringView> T>
-  class SortKeyImpl {
+  CPP_template(typename T)(requires ad_utility::SimilarToAny<
+                           T, U8String, U8StringView>) class SortKeyImpl {
    public:
     SortKeyImpl() = default;
     explicit SortKeyImpl(U8StringView sortKey) : sortKey_(sortKey) {}

src/util/Algorithm.h

@@ -58,8 +58,10 @@ bool contains_if(const Container& container, const Predicate& predicate) {
  * @param destination Vector& to which to append
  * @param source Vector&& to append
  */
-template <typename T, ad_utility::SimilarTo<std::vector<T>> U>
-void appendVector(std::vector<T>& destination, U&& source) {
+CPP_template(typename T, typename U)(
+    requires ad_utility::SimilarTo<
+        std::vector<T>, U>) void appendVector(std::vector<T>& destination,
+                                              U&& source) {
   destination.insert(destination.end(),
                      ad_utility::makeForwardingIterator<U>(source.begin()),
                      ad_utility::makeForwardingIterator<U>(source.end()));

src/util/CancellationHandle.h

@@ -2,8 +2,8 @@
 //   Chair of Algorithms and Data Structures.
 //   Author: Robin Textor-Falconi <[email protected]>
 
-#ifndef QLEVER_CANCELLATIONHANDLE_H
-#define QLEVER_CANCELLATIONHANDLE_H
+#ifndef SRC_UTIL_CANCELLATION_HANDLE_H
+#define SRC_UTIL_CANCELLATION_HANDLE_H
 
 #include <absl/strings/str_cat.h>
 #include <gtest/gtest_prod.h>
@@ -156,10 +156,14 @@ class CancellationHandle {
   /// in the console that would otherwise be triggered by the watchdog.
   /// NOTE: The parameter state is expected to be one of `CHECK_WINDOW_MISSED`
   /// or `WAITING_FOR_CHECK`, otherwise it will violate the correctness check.
-  void pleaseWatchDog(CancellationState state,
-                      ad_utility::source_location location,
-                      const ad_utility::InvocableWithConvertibleReturnType<
-                          std::string_view> auto& stageInvocable)
+  CPP_template(typename StateFunc)(
+      requires ad_utility::InvocableWithConvertibleReturnType<
+          StateFunc,
+          std::string_view>) void pleaseWatchDog(CancellationState state,
+                                                 ad_utility::source_location
+                                                     location,
+                                                 const StateFunc&
+                                                     stageInvocable)
       requires WatchDogEnabled {
     using DurationType =
         std::remove_const_t<decltype(DESIRED_CANCELLATION_CHECK_INTERVAL)>;
@@ -215,12 +219,13 @@ class CancellationHandle {
   /// nothing otherwise. If `WatchDogEnabled` is true, this will log a warning
   /// if this check is not called frequently enough. It will contain the
   /// filename and line of the caller of this method.
-  template <ad_utility::InvocableWithConvertibleReturnType<std::string_view>
-                Func = decltype(detail::printNothing)>
-  AD_ALWAYS_INLINE void throwIfCancelled(
-      [[maybe_unused]] ad_utility::source_location location =
-          ad_utility::source_location::current(),
-      const Func& stageInvocable = detail::printNothing) {
+  CPP_template(typename Func = decltype(detail::printNothing))(
+      requires ad_utility::InvocableWithConvertibleReturnType<Func,
+                                                              std::string_view>)
+      AD_ALWAYS_INLINE void throwIfCancelled(
+          [[maybe_unused]] ad_utility::source_location location =
+              ad_utility::source_location::current(),
+          const Func& stageInvocable = detail::printNothing) {
     if constexpr (CancellationEnabled) {
       auto state = cancellationState_.load(std::memory_order_relaxed);
       if (state == CancellationState::NOT_CANCELLED) [[likely]] {
@@ -296,4 +301,4 @@ class CancellationHandle {
 using SharedCancellationHandle = std::shared_ptr<CancellationHandle<>>;
 }  // namespace ad_utility
 
-#endif  // QLEVER_CANCELLATIONHANDLE_H
+#endif  // SRC_UTIL_CANCELLATION_HANDLE_H

src/util/ConfigManager/ConfigManager.cpp

@@ -45,8 +45,10 @@ ConfigManager::HashMapEntry::HashMapEntry(Data&& data)
     : data_{std::make_unique<Data>(std::move(data))} {}
 
 // ____________________________________________________________________________
-template <SameAsAnyTypeIn<ConfigManager::HashMapEntry::Data> T>
-bool ConfigManager::HashMapEntry::implHolds() const {
+CPP_template_def(typename T)(
+    requires SameAsAnyTypeIn<
+        T, ConfigManager::HashMapEntry::Data>) bool ConfigManager::
+    HashMapEntry::implHolds() const {
   // Make sure, that it is not a null pointer.
   AD_CORRECTNESS_CHECK(data_);
 
@@ -64,10 +66,13 @@ bool ConfigManager::HashMapEntry::holdsSubManager() const {
 }
 
 // ____________________________________________________________________________
-template <SimilarToAnyTypeIn<ConfigManager::HashMapEntry::Data> ReturnType>
-requires std::is_object_v<ReturnType> std::optional<ReturnType*>
-ConfigManager::HashMapEntry::getConfigOptionOrSubManager(
-    ad_utility::SimilarTo<ConfigManager::HashMapEntry> auto& instance) {
+CPP_template_def(typename ReturnType, typename InstanceType)(
+    requires SimilarToAnyTypeIn<ReturnType, ConfigManager::HashMapEntry::Data>
+        CPP_and std::is_object_v<ReturnType>
+            CPP_and ad_utility::SimilarTo<ConfigManager::HashMapEntry,
+                                          InstanceType>)
+    std::optional<ReturnType*> ConfigManager::HashMapEntry::
+        getConfigOptionOrSubManager(InstanceType& instance) {
   using DecayReturnType = std::decay_t<ReturnType>;
   /*
   We cheat a bit, by using `implHolds`, because so we can reduce the amount
@@ -104,32 +109,31 @@ std::optional<const ConfigManager*> ConfigManager::HashMapEntry::getSubManager()
 }
 
 // ____________________________________________________________________________
-template <typename Visitor>
-requires std::invocable<Visitor, ConfigOption&> &&
-         std::invocable<Visitor, ConfigManager&>
-decltype(auto) ConfigManager::HashMapEntry::visit(Visitor&& vis) {
+CPP_template_def(typename Visitor)(
+    requires std::invocable<Visitor, ConfigOption&> CPP_and
+        std::invocable<Visitor, ConfigManager&>) decltype(auto)
+    ConfigManager::HashMapEntry::visit(Visitor&& vis) {
   return visitImpl(AD_FWD(vis), data_);
 }
-template <typename Visitor>
-requires std::invocable<Visitor, const ConfigOption&> &&
-         std::invocable<Visitor, const ConfigManager&>
-decltype(auto) ConfigManager::HashMapEntry::visit(Visitor&& vis) const {
+CPP_template_def(typename Visitor)(
+    requires std::invocable<Visitor, ConfigOption&> CPP_and
+        std::invocable<Visitor, ConfigManager&>) decltype(auto)
+    ConfigManager::HashMapEntry::visit(Visitor&& vis) const {
   return visitImpl(AD_FWD(vis), data_);
 }
 
 // ____________________________________________________________________________
-template <
-    typename Visitor,
-    ad_utility::SimilarTo<std::unique_ptr<ConfigManager::HashMapEntry::Data>>
-        PointerType>
-requires std::invocable<
-             Visitor, std::conditional_t<std::is_const_v<PointerType>,
-                                         const ConfigOption&, ConfigOption&>> &&
-         std::invocable<
-             Visitor, std::conditional_t<std::is_const_v<PointerType>,
-                                         const ConfigManager&, ConfigManager&>>
-decltype(auto) ConfigManager::HashMapEntry::visitImpl(Visitor&& vis,
-                                                      PointerType& data) {
+CPP_template_def(typename Visitor, typename PointerType)(
+    requires ad_utility::SimilarTo<
+        std::unique_ptr<ConfigManager::HashMapEntry::Data>, PointerType>
+        CPP_and std::invocable<
+            Visitor, std::conditional_t<std::is_const_v<PointerType>,
+                                        const ConfigOption&, ConfigOption&>>
+            CPP_and std::invocable<
+                Visitor, std::conditional_t<std::is_const_v<PointerType>,
+                                            const ConfigManager&,
+                                            ConfigManager&>>) decltype(auto)
+    ConfigManager::HashMapEntry::visitImpl(Visitor&& vis, PointerType& data) {
   // Make sure, that it is not a null pointer.
   AD_CORRECTNESS_CHECK(data);
 
@@ -150,13 +154,14 @@ void ConfigManager::verifyHashMapEntry(std::string_view jsonPathToEntry,
 }
 
 // ____________________________________________________________________________
-template <typename Visitor>
-requires ad_utility::InvocableWithExactReturnType<
-             Visitor, void, std::string_view, ConfigManager&> &&
-         ad_utility::InvocableWithExactReturnType<
-             Visitor, void, std::string_view, ConfigOption&>
-void ConfigManager::visitHashMapEntries(Visitor&& vis, bool sortByCreationOrder,
-                                        std::string_view pathPrefix) const {
+CPP_template_def(typename Visitor)(
+    requires ad_utility::InvocableWithExactReturnType<
+        Visitor, void, std::string_view, ConfigManager&>
+        CPP_and ad_utility::InvocableWithExactReturnType<
+            Visitor, void, std::string_view,
+            ConfigOption&>) void ConfigManager::
+    visitHashMapEntries(Visitor&& vis, bool sortByCreationOrder,
+                        std::string_view pathPrefix) const {
   // For less code duplication.
   using Pair = decltype(configurationOptions_)::value_type;
 
@@ -188,17 +193,18 @@ void ConfigManager::visitHashMapEntries(Visitor&& vis, bool sortByCreationOrder,
 }
 
 // ____________________________________________________________________________
-template <
-    SimilarTo<ad_utility::HashMap<std::string, ConfigManager::HashMapEntry>>
+CPP_template_def(typename HashMapType, typename Callable)(
+    requires SimilarTo<
+        ad_utility::HashMap<std::string, ConfigManager::HashMapEntry>,
         HashMapType>
-requires std::is_object_v<HashMapType> auto ConfigManager::allHashMapEntries(
-    HashMapType& hashMap, std::string_view pathPrefix,
-    const ad_utility::InvocableWithSimilarReturnType<
-        bool, const HashMapEntry&> auto& predicate)
-    -> std::conditional_t<
-        std::is_const_v<HashMapType>,
-        const std::vector<std::pair<const std::string, const HashMapEntry&>>,
-        std::vector<std::pair<std::string, HashMapEntry&>>> {
+        CPP_and std::is_object_v<HashMapType>) auto ConfigManager::
+    allHashMapEntries(HashMapType& hashMap, std::string_view pathPrefix,
+                      const Callable& predicate)
+        -> std::conditional_t<
+            std::is_const_v<HashMapType>,
+            const std::vector<
+                std::pair<const std::string, const HashMapEntry&>>,
+            std::vector<std::pair<std::string, HashMapEntry&>>> {
   std::conditional_t<
       std::is_const_v<HashMapType>,
       std::vector<std::pair<const std::string, const HashMapEntry&>>,
@@ -255,12 +261,13 @@ requires std::is_object_v<HashMapType> auto ConfigManager::allHashMapEntries(
 }
 
 // ____________________________________________________________________________
-template <QL_CONCEPT_OR_TYPENAME(SameAsAny<ConfigOption&, const ConfigOption&>)
-              ReturnReference>
-std::vector<std::pair<std::string, ReturnReference>>
-ConfigManager::configurationOptionsImpl(
-    SimilarTo<ad_utility::HashMap<std::string, HashMapEntry>> auto&
-        configurationOptions) {
+CPP_template_def(typename ConfigOptions, typename ReturnReference)(
+    requires SameAsAny<ReturnReference, ConfigOption&, const ConfigOption&>
+        CPP_and SimilarTo<
+            ad_utility::HashMap<std::string, ConfigManager::HashMapEntry>,
+            ConfigOptions>)
+    std::vector<std::pair<std::string, ReturnReference>> ConfigManager::
+        configurationOptionsImpl(ConfigOptions& configurationOptions) {
   return ad_utility::transform(
       allHashMapEntries(
           configurationOptions, "",
@@ -274,13 +281,15 @@ ConfigManager::configurationOptionsImpl(
 // ____________________________________________________________________________
 std::vector<std::pair<std::string, ConfigOption&>>
 ConfigManager::configurationOptions() {
-  return configurationOptionsImpl<ConfigOption&>(configurationOptions_);
+  return configurationOptionsImpl<decltype(configurationOptions_),
+                                  ConfigOption&>(configurationOptions_);
 }
 
 // ____________________________________________________________________________
 std::vector<std::pair<std::string, const ConfigOption&>>
 ConfigManager::configurationOptions() const {
-  return configurationOptionsImpl<const ConfigOption&>(configurationOptions_);
+  return configurationOptionsImpl<const decltype(configurationOptions_),
+                                  const ConfigOption&>(configurationOptions_);
 }
 
 // ____________________________________________________________________________
@@ -857,9 +866,10 @@ bool ConfigManager::containsOption(const ConfigOption& opt) const {
 }
 
 // ____________________________________________________________________________
-template <QL_CONCEPT_OR_TYPENAME(ConfigOptionOrManager) T>
-void ConfigManager::ConfigurationDocValidatorAssignment::addEntryUnderKey(
-    const T& key, const ConfigOptionValidatorManager& manager) {
+CPP_template_def(typename T)(
+    requires ConfigOptionOrManager<T>) void ConfigManager::
+    ConfigurationDocValidatorAssignment::addEntryUnderKey(
+        const T& key, const ConfigOptionValidatorManager& manager) {
   getHashMapBasedOnType<T>()[&key].push_back(&manager);
 }
 // Explicit instantiation for `ConfigOption` and `ConfigManager`.
@@ -871,9 +881,9 @@ template void ConfigManager::ConfigurationDocValidatorAssignment::
                                     const ConfigOptionValidatorManager&);
 
 // ____________________________________________________________________________
-template <QL_CONCEPT_OR_TYPENAME(ConfigOptionOrManager) T>
-auto ConfigManager::ConfigurationDocValidatorAssignment::getEntriesUnderKey(
-    const T& key) const -> ValueGetterReturnType {
+CPP_template(typename T)(requires ConfigOptionOrManager<T>) auto ConfigManager::
+    ConfigurationDocValidatorAssignment::getEntriesUnderKey(const T& key) const
+    -> ValueGetterReturnType {
   // The concerned hash map.
   const MemoryAdressHashMap<T>& hashMap{getHashMapBasedOnType<T>()};