Add support for string <-> selection list serialization

src/commands.cc

@@ -1479,6 +1479,20 @@ const CommandDesc set_register_cmd = {
     }
 };
 
+const CommandDesc select_cmd = {
+    "select",
+    nullptr,
+    "select <selections_desc>: select given selections",
+    ParameterDesc{{}, ParameterDesc::Flags::None, 1, 1},
+    CommandFlags::None,
+    CommandHelper{},
+    CommandCompleter{},
+    [](const ParametersParser& parser, Context& context)
+    {
+        context.selections() = selection_list_from_string(context.buffer(), parser[0]);
+    }
+};
+
 const CommandDesc change_working_directory_cmd = {
     "cd",
     nullptr,
@@ -1574,6 +1588,7 @@ void register_commands()
     register_command(face_cmd);
     register_command(set_client_name_cmd);
     register_command(set_register_cmd);
+    register_command(select_cmd);
     register_command(change_working_directory_cmd);
 }
 

src/main.cc

@@ -123,18 +123,11 @@ void register_env_vars()
         }, {
             "selection_desc",
             [](StringView name, const Context& context)
-            { auto& sel = context.selections().main();
-              auto beg = sel.min();
-              return format("{}.{}+{}", beg.line + 1, beg.column + 1,
-                            context.buffer().distance(beg, sel.max())+1); }
+            { return selection_to_string(context.buffer(), context.selections().main()); }
         }, {
             "selections_desc",
             [](StringView name, const Context& context)
-            { return join(transformed(context.selections(), [&](const Selection& sel) {
-                    auto beg = sel.min();
-                    return format("{}.{}+{}", beg.line + 1, beg.column + 1,
-                                  context.buffer().distance(beg, sel.max())+1);
-                }), ':'); }
+            { return selection_list_to_string(context.selections()); }
         }, {
             "window_width",
             [](StringView name, const Context& context) -> String

src/selection.cc

@@ -542,4 +542,44 @@ void SelectionList::erase()
     m_buffer->check_invariant();
 }
 
+String selection_to_string(const Buffer& buffer, const Selection& selection)
+{
+    auto& cursor = selection.cursor();
+    auto& anchor = selection.anchor();
+    ByteCount distance = buffer.distance(anchor, cursor);
+    return format("{}.{}{}{}", anchor.line + 1, anchor.column + 1,
+                  distance < 0 ? '-' : '+', abs(distance));
+}
+
+String selection_list_to_string(const SelectionList& selections)
+{
+    const auto& buffer = selections.buffer();
+    return join(transformed(selections, [&buffer](const Selection& s)
+                            { return selection_to_string(buffer, s); }),
+                ':', false);
+}
+
+Selection selection_from_string(const Buffer& buffer, StringView desc)
+{
+    auto dot = find(desc, '.');
+    auto sign = std::find_if(dot, desc.end(), [](char c) { return c == '+' or c == '-'; });
+
+    if (dot == desc.end() or sign == desc.end())
+        throw runtime_error(format("'{}' does not follow <line>.<column>+<len> format", desc));
+
+    LineCount line = str_to_int({desc.begin(), dot}) - 1;
+    ByteCount column = str_to_int({dot+1, sign}) - 1;
+    ByteCoord anchor{line, column};
+    ByteCount count = (*sign == '+' ? 1 : -1) * str_to_int({sign+1, desc.end()});
+    return Selection{anchor, buffer.advance(anchor, count)};
+}
+
+SelectionList selection_list_from_string(Buffer& buffer, StringView desc)
+{
+    Vector<Selection> sels;
+    for (auto sel_desc : split(desc, ':'))
+        sels.push_back(selection_from_string(buffer, sel_desc));
+    return {buffer, std::move(sels)};
+}
+
 }

src/selection.hh

@@ -142,6 +142,11 @@ private:
 
 Vector<Selection> compute_modified_ranges(Buffer& buffer, size_t timestamp);
 
+String selection_to_string(const Buffer& buffer, const Selection& selection);
+String selection_list_to_string(const SelectionList& selection);
+Selection selection_from_string(const Buffer& buffer, StringView desc);
+SelectionList selection_list_from_string(Buffer& buffer, StringView desc);
+
 }
 
 #endif // selection_hh_INCLUDED