IncrementalInserter: support OpenLineBelow and OpenLineAbove mode

src/main.cc

@@ -504,6 +504,8 @@ std::unordered_map<char, std::function<void (Window& window, int count)>> keymap
     { 'c', do_change },
     { 'i', [](Window& window, int count) { do_insert(window, IncrementalInserter::Mode::Insert); } },
     { 'a', [](Window& window, int count) { do_insert(window, IncrementalInserter::Mode::Append); } },
+    { 'o', [](Window& window, int count) { do_insert(window, IncrementalInserter::Mode::OpenLineBelow); } },
+    { 'O', [](Window& window, int count) { do_insert(window, IncrementalInserter::Mode::OpenLineAbove); } },
 
     { 'g', do_go },
 

src/window.cc

@@ -371,7 +371,29 @@ IncrementalInserter::IncrementalInserter(Window& window, Mode mode)
 
     for (auto& sel : m_window.m_selections)
     {
-        const BufferIterator& pos = mode == Mode::Append ? sel.end() : sel.begin();
+        BufferIterator pos;
+        switch (mode)
+        {
+        case Mode::Insert: pos = sel.begin(); break;
+        case Mode::Append: pos = sel.end(); break;
+        case Mode::Change: pos = sel.begin(); break;
+
+        case Mode::OpenLineBelow:
+            pos = sel.end();
+            while (not pos.is_end() and *pos != '\n')
+                ++pos;
+            ++pos;
+            window.m_buffer.insert(pos, "\n");
+            break;
+
+        case Mode::OpenLineAbove:
+            pos = sel.begin();
+            while (not pos.is_begin() and *pos != '\n')
+                --pos;
+            window.m_buffer.insert(pos, "\n");
+            ++pos;
+            break;
+        }
         sel = Selection(pos, pos);
     }
 }

src/window.hh

@@ -124,7 +124,9 @@ public:
     {
         Insert,
         Append,
-        Change
+        Change,
+        OpenLineBelow,
+        OpenLineAbove
     };
 
     IncrementalInserter(Window& window, Mode mode = Mode::Insert);