From 6faafa7b47b9e2bba173983bb827f1179aa4f4aa Mon Sep 17 00:00:00 2001
From: "Timur A. Fatkhullin" <timur@sao.ru>
Date: Tue, 23 Jun 2026 19:14:19 +0300
Subject: [PATCH] ...

---
 include/snipplib/utils/snplib_keyvalue.h | 94 ++++++++++++++++++++++++
 include/snipplib/utils/snplib_string.h   | 45 ++++++++++++
 2 files changed, 139 insertions(+)

diff --git a/include/snipplib/utils/snplib_keyvalue.h b/include/snipplib/utils/snplib_keyvalue.h
index 2936390..7295a76 100644
--- a/include/snipplib/utils/snplib_keyvalue.h
+++ b/include/snipplib/utils/snplib_keyvalue.h
@@ -126,6 +126,73 @@ public:
     }
 
 
+    template <std::ranges::range OR>
+        requires(std::ranges::output_range<OR, std::ranges::range_value_t<OR>> &&
+                 snplib_char_range_c<std::ranges::range_value_t<OR>>)
+    OR valueSeq(size_t start = 0, size_t N = std::numeric_limits<size_t>::max()) const
+    {
+        using el_t = std::ranges::range_value_t<OR>;
+
+        OR res;
+
+        if (N == 0 || _valueSeq.empty() || start >= _valueSeq.size()) {
+            return res;
+        }
+
+        auto elems = _valueSeq | std::views::drop(start) | std::views::take(N);
+
+        if constexpr (std::same_as<OR, decltype(_valueSeq)>) {
+            std::ranges::copy(elems, std::back_inserter(res));
+        } else {
+            std::ranges::for_each(elems, [&res](auto const& e) {
+                if constexpr (std::constructible_from<el_t, std::string_view::const_iterator,
+                                                      std::string_view::const_iterator>) {
+                    std::back_inserter(el_t{e.cbegin(), e.cend()}, std::back_inserter(res));
+                } else if constexpr (std::constructible_from<el_t, std::string_view>) {
+                    std::back_inserter(el_t{e}, std::back_inserter(res));
+                } else {
+                    static_assert(false, "Incompatible types: cannot create output element!");
+                }
+            });
+        }
+
+        return res;
+    }
+
+    std::vector<std::string_view> valueSeq(size_t start = 0, size_t N = std::numeric_limits<size_t>::max()) const
+    {
+        return valueSeq<std::vector<std::string_view>>(start, N);
+    }
+
+
+    template <snplib_char_range_c OR>
+    OR valueJoinSeq(size_t start = 0, size_t N = std::numeric_limits<size_t>::max()) const
+    {
+        if (N == 0 || _valueSeq.empty() || start >= _valueSeq.size()) {
+            return OR();
+        }
+
+        auto last_idx = start + N;
+        if (last_idx >= _valueSeq.size()) {
+            last_idx = _valueSeq.size() - 1;
+        }
+
+
+        if constexpr (std::constructible_from<OR, std::string_view::const_iterator, std::string_view::const_iterator>) {
+            return OR{_valueSeq[start].cbegin(), _valueSeq[last_idx].cend()};
+        } else if constexpr (std::constructible_from<OR, std::string_view>) {
+            return OR{std::string_view{_valueSeq[start].begin(), _valueSeq[last_idx].end()}};
+        } else if constexpr (snplib_output_char_range_c<OR>) {
+            OR res;
+
+            std::copy(_valueSeq[start].begin(), _valueSeq[last_idx].end(), std::back_inserter(res));
+
+            return res;
+        } else {
+            static_assert(false, "Incompatible types: cannot create output range!");
+        }
+    }
+
     template <snplib_serializable_c KeyT, snplib_serialization_params_c SParT = snplib_serialization_params_t>
         requires mutableContent
     error_t setKey(KeyT&& key, SParT const& sparams = snplib_serialization_params_t{})
@@ -138,6 +205,33 @@ public:
         return {};
     }
 
+    template <snplib_serializable_c ValueT, snplib_serialization_params_c SParT = snplib_serialization_params_t>
+        requires mutableContent
+    error_t setValue(ValueT&& value, SParT const& sparams = snplib_serialization_params_t{})
+    {
+        auto err = snplib_serializer_t<std::remove_cvref_t<ValueT>>(_key, std::forward<ValueT>(value), sparams);
+        if (err) {
+            return snplib_deduced_error(err, std::errc::invalid_argument);
+        }
+
+        return {};
+    }
+
+
+    template <snplib_serializable_c KeyT,
+              snplib_serializable_c ValueT,
+              snplib_serialization_params_c SParT = snplib_serialization_params_t>
+        requires mutableContent
+    error_t setKeyValue(KeyT&& key, ValueT&& value, SParT const& sparams = snplib_serialization_params_t{})
+    {
+        auto err = setKey(std::forward<KeyT>(key), sparams);
+        if (err) {
+            return err;
+        }
+
+        return setValue(std::forward<KeyT>(value), sparams);
+    }
+
 protected:
     std::
         conditional_t<mutableContent, std::string, std::conditional_t<stringViewContent, std::string_view, std::string>>
diff --git a/include/snipplib/utils/snplib_string.h b/include/snipplib/utils/snplib_string.h
index d5909cd..296bc90 100644
--- a/include/snipplib/utils/snplib_string.h
+++ b/include/snipplib/utils/snplib_string.h
@@ -194,6 +194,51 @@ static constexpr OR snplib_split_char_range(IR&& input,
 }
 
 
+template <snplib_output_char_range_c OR, std::ranges::input_range IR, snplib_input_char_range_c DR>
+OR snplib_join_char_ranges(IR&& input, DR&& delim, size_t start = 0, size_t N = std::numeric_limits<size_t>::max())
+    requires(snplib_char_range_c<std::ranges::range_value_t<IR>>)
+{
+    using el_t = std::ranges::range_value_t<IR>;
+
+    if constexpr (std::is_pointer_v<std::decay_t<DR>>) {  // char*, const char*, char[]
+        if constexpr (std::constructible_from<el_t, decltype(std::begin(delim)), decltype(std::end(delim))>) {
+            return snplib_join_char_ranges<OR>(std::forward<IR>(input), el_t(std::begin(delim), std::end(delim)), start,
+                                               N);
+        } else {
+            return snplib_join_char_ranges<OR>(std::forward<IR>(input), std::string_view(delim), start, N);
+        }
+    } else {
+        OR res;
+
+        using d_t = std::remove_cvref_t<DR>;
+
+        if constexpr (std::same_as<el_t, d_t>) {
+            std::ranges::copy(std::forward<IR>(input) | std::views::join_with(std::forward<DR>(delim)),
+                              std::back_inserter(res));
+        } else if constexpr (snplib_char_view_c<el_t> && std::ranges::viewable_range<d_t>) {
+            el_t d{delim.begin(), delim.end()};
+
+            std::ranges::copy(std::forward<IR>(input) | std::views::join_with(d), std::back_inserter(res));
+        } else if constexpr (snplib_output_char_range_c<el_t>) {
+            el_t d;
+            std::ranges::copy(delim, std::back_inserter(d));
+
+            std::ranges::copy(std::forward<IR>(input) | std::views::join_with(d), std::back_inserter(res));
+        } else {  // generic case
+            for (auto const& el : std::forward<IR>(input) | std::views::take(std::ranges::size(input) - 1)) {
+                std::ranges::copy(el, std::back_inserter(res));
+                std::ranges::copy(delim, std::back_inserter(res));
+            }
+            // add the last elements
+            std::ranges::copy(std::forward<IR>(input) | std::views::reverse | std::views::take(1),
+                              std::back_inserter(res));
+        }
+
+        return res;
+    }
+}
+
+
 template <typename T, snplib_input_char_range_c R>
 static std::optional<T> snplib_num_from_range(R&& r)
     requires((std::integral<T> || std::floating_point<T>) && std::ranges::contiguous_range<R>)