--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/functional.h Fri Feb 28 19:24:33 2020 +0200
@@ -0,0 +1,159 @@
+/*
+ * LDForge: LDraw parts authoring CAD
+ * Copyright (C) 2020 Teemu Piippo
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+#include <algorithm>
+#include <functional>
+#include <QVector>
+#include <QSet>
+#include <QList>
+
+namespace fn
+{
+ template<typename C>
+ class InsertIterator;
+}
+
+/**
+ * Like std::back_inserter but calls x.insert(v) instead
+ */
+template<typename C>
+class fn::InsertIterator
+{
+public:
+ InsertIterator(C& container) :
+ container{container} {}
+ auto operator*()
+ {
+ return *this;
+ }
+ auto operator++()
+ {
+ return *this;
+ }
+ auto operator++(int)
+ {
+ return *this;
+ }
+ template<typename T>
+ auto operator=(T&& value)
+ {
+ this->container.insert(std::forward<T>(value));
+ return *this;
+ }
+private:
+ C& container;
+};
+
+namespace fn
+{
+ // Constructs a fn::InsertIterator
+ template<typename C>
+ InsertIterator<C> makeInsertIterator(C& container)
+ {
+ return InsertIterator<C>{container};
+ }
+
+ // Constructs a back_inserter for std::vector
+ template<typename T>
+ auto makeDefaultInserter(std::vector<T>& vec)
+ {
+ return std::back_inserter(vec);
+ }
+
+ // Constructs a back_inserter for QVector
+ template<typename T>
+ auto makeDefaultInserter(QVector<T>& vec)
+ {
+ return std::back_inserter(vec);
+ }
+
+ // Constructs a back_inserter for QList
+ template<typename T>
+ auto makeDefaultInserter(QList<T>& vec)
+ {
+ return std::back_inserter(vec);
+ }
+
+ // Constructs an fn::InsertIterator for QSet
+ template<typename T>
+ auto makeDefaultInserter(QSet<T>& vec)
+ {
+ return InsertIterator(vec);
+ }
+
+ // Changes the value type of C
+ template<typename C, typename TT>
+ struct ChangeContainerValueType
+ {
+ };
+
+ // Changes the value type of std::vector
+ template<typename T, typename TT>
+ struct ChangeContainerValueType<std::vector<T>, TT>
+ {
+ using type = std::vector<TT>;
+ };
+
+ // Changes the value type of QVector
+ template<typename T, typename TT>
+ struct ChangeContainerValueType<QVector<T>, TT>
+ {
+ using type = QVector<TT>;
+ };
+
+ // Changes the value type of QSet
+ template<typename T, typename TT>
+ struct ChangeContainerValueType<QSet<T>, TT>
+ {
+ using type = QSet<TT>;
+ };
+
+ // Changes the value type of QList
+ template<typename T, typename TT>
+ struct ChangeContainerValueType<QList<T>, TT>
+ {
+ using type = QList<TT>;
+ };
+
+ // Changes the value type of C
+ template<typename C, typename TT>
+ using ChangeContainerValueType_t = typename ChangeContainerValueType<C, TT>::type;
+
+ /**
+ * \brief Applies \c function to all elements of \c container
+ * \param container Container to iterate
+ * \param function Function to apply
+ * \param Rt result type. If not provided, a suitable result type is deduced from inputs
+ * \returns mapped result container
+ */
+ template<typename Rt = void, typename C, typename Fn>
+ auto map(C&& container, Fn&& function)
+ {
+ using value_t = decltype(*std::declval<C>().begin());
+ using newvalue_t = std::result_of_t<Fn(value_t)>;
+ using result_t = std::conditional_t<
+ std::is_same_v<Rt, void>,
+ ChangeContainerValueType_t<std::remove_reference_t<C>, newvalue_t>,
+ Rt>;
+ result_t result;
+ result.reserve(std::end(container) - std::begin(container));
+ std::transform(std::begin(container), std::end(container), makeDefaultInserter(result), function);
+ return result;
+ }
+}