Implement %val{selections_char_desc}

Fixes #3194

doc/pages/expansions.asciidoc

@@ -311,6 +311,12 @@ The following expansions are supported (with required context _in italics_):
     the number of bytes from the start of the line to the cursor (like
     `%val{cursor_column}`), and all are 1-based decimal integers
 
+*%val{selections_char_desc}*::
+    _in window scope_ +
+    unquoted list of the ranges of all selections, in the same format as
+    `%val{selection_desc}`, except that the columns are in codepoints rather
+    than bytes
+
 *%val{selections_desc}*::
     _in window scope_ +
     unquoted list of the ranges of all selections, in the same format as

src/main.cc

@@ -252,7 +252,11 @@ static const EnvVarDesc builtin_env_vars[] = { {
     }, {
         "selections_desc", false,
         [](StringView name, const Context& context, Quoting quoting)
-        { return selection_list_to_string(context.selections()); }
+        { return selection_list_to_string<false>(context.selections()); }
+    }, {
+        "selections_char_desc", false,
+        [](StringView name, const Context& context, Quoting quoting)
+        { return selection_list_to_string<true>(context.selections()); }
     }, {
         "selection_length", false,
         [](StringView name, const Context& context, Quoting quoting) -> String
@@ -793,7 +797,7 @@ int run_server(StringView session, StringView server_init,
                 kak_assert(local_client);
                 const String client_name = local_client->context().name();
                 const String buffer_name = local_client->context().buffer().name();
-                const String selections = selection_list_to_string(local_client->context().selections());
+                const String selections = selection_list_to_string<false>(local_client->context().selections());
 
                 ClientManager::instance().remove_client(*local_client, true, 0);
                 client_manager.clear_client_trash();

src/selection.cc

@@ -480,13 +480,13 @@ String selection_to_string(const Selection& selection)
                   cursor.line + 1, cursor.column + 1);
 }
 
-String selection_list_to_string(const SelectionList& selections)
+String selection_to_string_char(const Buffer& buffer, const Selection& selection)
 {
-    auto beg = &*selections.begin(), end = &*selections.end();
-    auto main = beg + selections.main_index();
-    using View = ConstArrayView<Selection>;
-    return join(concatenated(View{main, end}, View{beg, main}) |
-                transform(selection_to_string), ' ', false);
+    const auto& cursor = selection.cursor();
+    const auto& anchor = selection.anchor();
+    return format("{}.{},{}.{}",
+                  anchor.line + 1, buffer[anchor.line].char_count_to(anchor.column) + 1,
+                  cursor.line + 1, buffer[cursor.line].char_count_to(cursor.column) + 1);
 }
 
 Selection selection_from_string(StringView desc)

src/selection.hh

@@ -95,7 +95,6 @@ struct SelectionList
     SelectionList(Buffer& buffer, Vector<Selection> s, size_t timestamp);
 
     void update(bool merge = true);
-
     void check_invariant() const;
 
     const Selection& main() const { return (*this)[m_main]; }
@@ -157,9 +156,27 @@ private:
 
 Vector<Selection> compute_modified_ranges(const Buffer& buffer, size_t timestamp);
 
-String selection_to_string(const Selection& selection);
-String selection_list_to_string(const SelectionList& selection);
 Selection selection_from_string(StringView desc);
+String selection_to_string(const Selection& selection);
+String selection_to_string_char(const Buffer& buffer, const Selection& selection);
+
+template<bool char_columns>
+String selection_list_to_string(const SelectionList& selections)
+{
+    auto& buffer = selections.buffer();
+    kak_assert(selections.timestamp() == buffer.timestamp());
+
+    auto to_string = [&](const Selection& selection) {
+        return char_columns ? selection_to_string_char(buffer, selection)
+                            : selection_to_string(selection);
+    };
+
+    auto beg = &*selections.begin(), end = &*selections.end();
+    auto main = beg + selections.main_index();
+    using View = ConstArrayView<Selection>;
+    return join(concatenated(View{main, end}, View{beg, main}) |
+                transform(to_string), ' ', false);
+}
 
 template<class StringArray>
 SelectionList selection_list_from_strings(Buffer& buffer, StringArray&& descs, size_t timestamp, size_t main)

test/compose/selections_char_desc-expansion/in

@@ -0,0 +1,4 @@
+sin%(gle)-byte
+%(λx.)λy.y x - start on wide char
+	∃e∈%(C.∀)g∈C.g⊗e≡e⊗g≡e - tabs, ending on wide char
+	%(x̦̏)- combining characters

test/compose/selections_char_desc-expansion/kak_selections_char_desc

@@ -0,0 +1 @@
+4.2,4.4 1.4,1.6 2.1,2.3 3.5,3.7