diff --git a/src/blackmisc/mapbuilder.h b/src/blackmisc/mapbuilder.h
new file mode 100644
index 000000000..b92560eeb
--- /dev/null
+++ b/src/blackmisc/mapbuilder.h
@@ -0,0 +1,74 @@
+/* Copyright (C) 2021
+ * swift project Community / Contributors
+ *
+ * This file is part of swift project. It is subject to the license terms in the LICENSE file found in the top-level
+ * directory of this distribution. No part of swift project, including this file, may be copied, modified, propagated,
+ * or distributed except according to the terms contained in the LICENSE file.
+ */
+
+//! \file
+
+#ifndef BLACKMISC_MAPBUILDER_H
+#define BLACKMISC_MAPBUILDER_H
+
+#include "blackmisc/blackmiscexport.h"
+#include "blackmisc/range.h"
+#include <QMap>
+#include <QHash>
+#include <QList>
+#include <algorithm>
+#include <iterator>
+#include <map>
+
+namespace BlackMisc
+{
+    /*!
+     * Build a QMap more efficiently when calling insert() in a for loop.
+     */
+    template <typename K, typename V>
+    class CMapBuilder
+    {
+    public:
+        //! Add an key/value pair to the map. Runs in amortized constant time.
+        template <typename... Ts>
+        void insert(Ts &&... keyAndValue) { m_list.push_back(std::make_pair(std::forward<Ts>(keyAndValue)...)); }
+
+        //! True if no pairs have been inserted.
+        bool isEmpty() const { return m_list.isEmpty(); }
+
+        //! Return a container with unique keys. Runs in log-linear time.
+        //! @{
+        operator QMap<K, V>() const & { return convertToMap(sortAndDeduplicate(m_list)); }
+        operator QMap<K, V>() && { return convertToMap(sortAndDeduplicate(std::move(m_list))); }
+        operator QHash<K, V>() const & { return convertTo<QHash>(sortAndDeduplicate(m_list)); }
+        operator QHash<K, V>() && { return convertTo<QHash>(sortAndDeduplicate(std::move(m_list))); }
+        operator std::map<K, V>() const & { return convertTo<std::map>(sortAndDeduplicate(m_list)); }
+        operator std::map<K, V>() && { return convertTo<std::map>(sortAndDeduplicate(std::move(m_list))); }
+        //! @}
+
+    private:
+        QList<std::pair<K, V>> m_list;
+
+        static QList<std::pair<K, V>> sortAndDeduplicate(QList<std::pair<K, V>> list)
+        {
+            std::sort(list.begin(), list.end(), [](auto &&a, auto &&b) { return std::less<>()(a.first, b.first); });
+            list.erase(std::unique(list.begin(), list.end(), [](auto &&a, auto &&b) { return a.first == b.first; }), list.end());
+            return list;
+        }
+
+        template <template <typename...> class C>
+        static C<K, V> convertTo(QList<std::pair<K, V>> &&list)
+        {
+            return C<K, V>(std::make_move_iterator(list.begin()), std::make_move_iterator(list.end()));
+        }
+
+        static QMap<K, V> convertToMap(QList<std::pair<K, V>> &&list)
+        {
+            QMap<K, V> map;
+            for (auto &pair : makeRange(list).reverse()) { map.insert(map.cbegin(), std::move(pair.first), std::move(pair.second)); }
+            return map;
+        }
+    };
+}
+
+#endif
diff --git a/src/blackmisc/sequence.h b/src/blackmisc/sequence.h
index f449098d0..3e05a0cdd 100644
--- a/src/blackmisc/sequence.h
+++ b/src/blackmisc/sequence.h
@@ -65,6 +65,10 @@ namespace BlackMisc
         //! By QList of type T.
         CSequence(const QList<T> &list) : m_impl(list.toVector()) {}
 
+        //! Range constructor.
+        template <typename It>
+        CSequence(It first, It last) : m_impl(first, last) {}
+
         //! Copy constructor.
         CSequence(const CSequence &other) = default;
 
diff --git a/src/blackmisc/setbuilder.h b/src/blackmisc/setbuilder.h
new file mode 100644
index 000000000..1ee94312c
--- /dev/null
+++ b/src/blackmisc/setbuilder.h
@@ -0,0 +1,78 @@
+/* Copyright (C) 2021
+ * swift project Community / Contributors
+ *
+ * This file is part of swift project. It is subject to the license terms in the LICENSE file found in the top-level
+ * directory of this distribution. No part of swift project, including this file, may be copied, modified, propagated,
+ * or distributed except according to the terms contained in the LICENSE file.
+ */
+
+//! \file
+
+#ifndef BLACKMISC_SETBUILDER_H
+#define BLACKMISC_SETBUILDER_H
+
+#include "blackmisc/blackmiscexport.h"
+#include <QSet>
+#include <QList>
+#include <QVector>
+#include <QStringList>
+#include <algorithm>
+#include <iterator>
+#include <vector>
+#include <set>
+
+namespace BlackMisc
+{
+    /*!
+     * Build a QSet more efficiently when calling insert() in a for loop.
+     */
+    template <typename T>
+    class CSetBuilder
+    {
+    public:
+        //! Add an element to the set. Runs in amortized constant time.
+        //! @{
+        void insert(const T &value) { m_list.push_back(value); }
+        void insert(T &&value) { m_list.push_back(std::move(value)); }
+        //! @}
+
+        //! True if no elements have been inserted.
+        bool isEmpty() const { return m_list.isEmpty(); }
+
+        //! Return a container of unique elements. Runs in log-linear time.
+        //! @{
+        operator QList<T>() const & { return sortAndDeduplicate(m_list); }
+        operator QList<T>() && { return sortAndDeduplicate(std::move(m_list)); }
+        operator QSet<T>() const & { return convertTo<QSet>(sortAndDeduplicate(m_list)); }
+        operator QSet<T>() && { return convertTo<QSet>(sortAndDeduplicate(std::move(m_list))); }
+        operator std::set<T>() const & { return convertTo<std::set>(sortAndDeduplicate(m_list)); }
+        operator std::set<T>() && { return convertTo<std::set>(sortAndDeduplicate(std::move(m_list))); }
+        operator QVector<T>() const & { return convertTo<QVector>(sortAndDeduplicate(m_list)); }
+        operator QVector<T>() && { return convertTo<QVector>(sortAndDeduplicate(std::move(m_list))); }
+        operator std::vector<T>() const & { return convertTo<std::vector>(sortAndDeduplicate(m_list)); }
+        operator std::vector<T>() && { return convertTo<std::vector>(sortAndDeduplicate(std::move(m_list))); }
+        template <typename U = T, typename = std::enable_if_t<std::is_same_v<U, QString>>>
+        operator QStringList() const & { return sortAndDeduplicate(m_list); }
+        template <typename U = T, typename = std::enable_if_t<std::is_same_v<U, QString>>>
+        operator QStringList() && { return sortAndDeduplicate(std::move(m_list)); }
+        //! @}
+
+    private:
+        QList<T> m_list;
+
+        static QList<T> sortAndDeduplicate(QList<T> list)
+        {
+            std::sort(list.begin(), list.end());
+            list.erase(std::unique(list.begin(), list.end()), list.end());
+            return list;
+        }
+
+        template <template <typename...> class C>
+        static C<T> convertTo(QList<T> &&list)
+        {
+            return C<T>(std::make_move_iterator(list.begin()), std::make_move_iterator(list.end()));
+        }
+    };
+}
+
+#endif