extract an Editor class from Window and refactor

7 files changed, 671 insertions, 591 deletions

diff --git a/src/editor.cc b/src/editor.cc
new file mode 100644
index 00000000..afce02db
--- /dev/null
+++ b/src/editor.cc
@@ -0,0 +1,340 @@
+#include "editor.hh"
+
+#include "exception.hh"
+#include "utils.hh"
+
+namespace Kakoune
+{
+
+namespace
+{
+
+struct scoped_undo_group
+{
+    scoped_undo_group(Buffer& buffer)
+        : m_buffer(buffer) { m_buffer.begin_undo_group(); }
+
+    ~scoped_undo_group()   { m_buffer.end_undo_group(); }
+private:
+    Buffer& m_buffer;
+};
+
+}
+
+Editor::Editor(Buffer& buffer)
+    : m_buffer(buffer),
+      m_current_inserter(nullptr)
+{
+    m_selections.push_back(SelectionList());
+    selections().push_back(Selection(buffer.begin(), buffer.begin()));
+}
+
+void Editor::erase()
+{
+    if (m_current_inserter == nullptr)
+    {
+        scoped_undo_group undo_group(m_buffer);
+        erase_noundo();
+    }
+    else
+        erase_noundo();
+}
+
+void Editor::erase_noundo()
+{
+    check_invariant();
+    for (auto& sel : selections())
+        m_buffer.modify(Modification::make_erase(sel.begin(), sel.end()));
+}
+
+void Editor::insert(const String& string)
+{
+    if (m_current_inserter == nullptr)
+    {
+        scoped_undo_group undo_group(m_buffer);
+        insert_noundo(string);
+    }
+    else
+        insert_noundo(string);
+}
+
+void Editor::insert_noundo(const String& string)
+{
+    for (auto& sel : selections())
+        m_buffer.modify(Modification::make_insert(sel.begin(), string));
+}
+
+void Editor::append(const String& string)
+{
+    if (m_current_inserter == nullptr)
+    {
+        scoped_undo_group undo_group(m_buffer);
+        append_noundo(string);
+    }
+    else
+        append_noundo(string);
+}
+
+void Editor::append_noundo(const String& string)
+{
+    for (auto& sel : selections())
+        m_buffer.modify(Modification::make_insert(sel.end(), string));
+}
+
+void Editor::replace(const std::string& string)
+{
+    if (m_current_inserter == nullptr)
+    {
+        scoped_undo_group undo_group(m_buffer);
+        erase_noundo();
+        insert_noundo(string);
+    }
+    else
+    {
+        erase_noundo();
+        insert_noundo(string);
+    }
+}
+
+void Editor::push_selections()
+{
+    SelectionList current_selections = selections();
+    m_selections.push_back(std::move(current_selections));
+}
+
+void Editor::pop_selections()
+{
+    if (m_selections.size() > 1)
+        m_selections.pop_back();
+    else
+        throw runtime_error("no more selections on stack");
+}
+
+void Editor::move_selections(const BufferCoord& offset, bool append)
+{
+    for (auto& sel : selections())
+    {
+        BufferCoord pos = m_buffer.line_and_column_at(sel.last());
+        BufferIterator last = m_buffer.iterator_at(pos + BufferCoord(offset));
+        sel = Selection(append ? sel.first() : last, last);
+    }
+}
+
+void Editor::clear_selections()
+{
+    check_invariant();
+    BufferIterator pos = selections().back().last();
+
+    if (*pos == '\n' and not pos.is_begin() and *(pos-1) != '\n')
+        --pos;
+
+    Selection sel = Selection(pos, pos);
+    selections().clear();
+    selections().push_back(std::move(sel));
+}
+
+void Editor::keep_selection(int index)
+{
+    check_invariant();
+
+    if (index < selections().size())
+    {
+        Selection sel = selections()[index];
+        selections().clear();
+        selections().push_back(std::move(sel));
+    }
+}
+
+void Editor::select(const BufferIterator& iterator)
+{
+    selections().clear();
+    selections().push_back(Selection(iterator, iterator));
+
+}
+
+void Editor::select(const Selector& selector, bool append)
+{
+    check_invariant();
+
+    if (not append)
+    {
+        for (auto& sel : selections())
+            sel = selector(sel.last());
+    }
+    else
+    {
+        for (auto& sel : selections())
+            sel.merge_with(selector(sel.last()));
+    }
+}
+
+struct nothing_selected : public runtime_error
+{
+    nothing_selected() : runtime_error("nothing was selected") {}
+};
+
+void Editor::multi_select(const MultiSelector& selector)
+{
+    check_invariant();
+
+    SelectionList new_selections;
+    for (auto& sel : selections())
+    {
+        SelectionList selections = selector(sel);
+        std::copy(selections.begin(), selections.end(),
+                  std::back_inserter(new_selections));
+    }
+    if (new_selections.empty())
+        throw nothing_selected();
+
+    selections() = std::move(new_selections);
+}
+
+BufferString Editor::selection_content() const
+{
+    check_invariant();
+
+    return m_buffer.string(selections().back().begin(),
+                           selections().back().end());
+}
+
+bool Editor::undo()
+{
+    return m_buffer.undo();
+}
+
+bool Editor::redo()
+{
+    return m_buffer.redo();
+}
+
+void Editor::check_invariant() const
+{
+    assert(not selections().empty());
+}
+
+struct id_not_unique : public runtime_error
+{
+    id_not_unique(const std::string& id)
+        : runtime_error("id not unique: " + id) {}
+};
+
+void Editor::add_filter(FilterAndId&& filter)
+{
+    if (m_filters.contains(filter.first))
+        throw id_not_unique(filter.first);
+    m_filters.append(std::forward<FilterAndId>(filter));
+}
+
+void Editor::remove_filter(const std::string& id)
+{
+    m_filters.remove(id);
+}
+
+CandidateList Editor::complete_filterid(const std::string& prefix,
+                                        size_t cursor_pos)
+{
+    return m_filters.complete_id<str_to_str>(prefix, cursor_pos);
+}
+
+void Editor::begin_incremental_insert(IncrementalInserter* inserter)
+{
+    assert(not m_current_inserter);
+    m_current_inserter = inserter;
+    m_buffer.begin_undo_group();
+
+    on_begin_incremental_insert();
+}
+
+void Editor::end_incremental_insert(IncrementalInserter* inserter)
+{
+    on_end_incremental_insert();
+
+    assert(m_current_inserter and m_current_inserter == inserter);
+    m_current_inserter = nullptr;
+    m_buffer.end_undo_group();
+}
+
+IncrementalInserter::IncrementalInserter(Editor& editor, Mode mode)
+    : m_editor(editor)
+{
+    m_editor.begin_incremental_insert(this);
+
+    if (mode == Mode::Change)
+        editor.erase_noundo();
+
+    for (auto& sel : m_editor.selections())
+    {
+        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:
+        case Mode::AppendAtLineEnd:
+            pos = m_editor.m_buffer.iterator_at_line_end(sel.end() - 1) - 1;
+            break;
+
+        case Mode::OpenLineAbove:
+        case Mode::InsertAtLineBegin:
+            pos = m_editor.m_buffer.iterator_at_line_begin(sel.begin());
+            if (mode == Mode::OpenLineAbove)
+                --pos;
+            break;
+        }
+        sel = Selection(pos, pos, sel.captures());
+
+        if (mode == Mode::OpenLineBelow or mode == Mode::OpenLineAbove)
+            apply(Modification::make_insert(pos, "\n"));
+    }
+}
+
+IncrementalInserter::~IncrementalInserter()
+{
+    move_cursors(BufferCoord(0, -1));
+    m_editor.end_incremental_insert(this);
+}
+
+void IncrementalInserter::apply(Modification&& modification) const
+{
+    for (auto filter : m_editor.m_filters)
+        filter.second(m_editor.buffer(), modification);
+    m_editor.buffer().modify(std::move(modification));
+}
+
+
+void IncrementalInserter::insert(const Editor::String& string)
+{
+    for (auto& sel : m_editor.selections())
+        apply(Modification::make_insert(sel.begin(), string));
+}
+
+void IncrementalInserter::insert_capture(size_t index)
+{
+    for (auto& sel : m_editor.selections())
+        m_editor.m_buffer.modify(Modification::make_insert(sel.begin(),
+                                                           sel.capture(index)));
+}
+
+void IncrementalInserter::erase()
+{
+    for (auto& sel : m_editor.selections())
+    {
+        sel = Selection(sel.first() - 1, sel.last() - 1);
+        apply(Modification::make_erase(sel.begin(), sel.end()));
+    }
+}
+
+void IncrementalInserter::move_cursors(const BufferCoord& offset)
+{
+    for (auto& sel : m_editor.selections())
+    {
+        BufferCoord pos = m_editor.m_buffer.line_and_column_at(sel.last());
+        BufferIterator it = m_editor.m_buffer.iterator_at(pos + offset);
+        sel = Selection(it, it);
+    }
+}
+
+}
diff --git a/src/editor.hh b/src/editor.hh
new file mode 100644
index 00000000..988564ce
--- /dev/null
+++ b/src/editor.hh
@@ -0,0 +1,115 @@
+#ifndef editor_hh_INCLUDED
+#define editor_hh_INCLUDED
+
+#include "buffer.hh"
+#include "selection.hh"
+#include "filter.hh"
+#include "idvaluemap.hh"
+#include "hooks_manager.hh"
+
+namespace Kakoune
+{
+
+class IncrementalInserter;
+
+// An Editor is a buffer mutator
+//
+// The Editor class provides methods to manipulate a set of selections
+// and to use these selections to mutate it's buffer.
+class Editor
+{
+public:
+    typedef BufferString String;
+    typedef std::function<Selection (const BufferIterator&)> Selector;
+    typedef std::function<SelectionList (const Selection&)>  MultiSelector;
+
+    Editor(Buffer& buffer);
+    virtual ~Editor() {}
+
+    Buffer& buffer() const { return m_buffer; }
+
+    void erase();
+    void insert(const String& string);
+    void append(const String& string);
+    void replace(const String& string);
+
+    void push_selections();
+    void pop_selections();
+
+    void move_selections(const BufferCoord& offset, bool append = false);
+    void clear_selections();
+    void keep_selection(int index);
+    void select(const BufferIterator& iterator);
+    void select(const Selector& selector, bool append = false);
+    void multi_select(const MultiSelector& selector);
+
+    BufferString selection_content() const;
+    const SelectionList& selections() const { return m_selections.back(); }
+
+    bool undo();
+    bool redo();
+
+    void add_filter(FilterAndId&& filter);
+    void remove_filter(const std::string& id);
+
+    CandidateList complete_filterid(const std::string& prefix,
+                                    size_t cursor_pos = std::string::npos);
+
+    bool is_inserting() const { return m_current_inserter != nullptr; }
+
+private:
+    void erase_noundo();
+    void insert_noundo(const String& string);
+    void append_noundo(const String& string);
+
+    SelectionList& selections() { return m_selections.back(); }
+
+    void check_invariant() const;
+
+    friend class IncrementalInserter;
+    IncrementalInserter* m_current_inserter;
+
+    void begin_incremental_insert(IncrementalInserter* inserter);
+    void end_incremental_insert(IncrementalInserter* inserter);
+    virtual void on_begin_incremental_insert() {}
+    virtual void on_end_incremental_insert() {}
+
+
+    Buffer&                             m_buffer;
+    std::vector<SelectionList>          m_selections;
+    idvaluemap<std::string, FilterFunc> m_filters;
+};
+
+// An IncrementalInserter manage insert mode
+class IncrementalInserter
+{
+public:
+    enum class Mode
+    {
+        Insert,
+        Append,
+        Change,
+        InsertAtLineBegin,
+        AppendAtLineEnd,
+        OpenLineBelow,
+        OpenLineAbove
+    };
+
+    IncrementalInserter(Editor& editor, Mode mode = Mode::Insert);
+    ~IncrementalInserter();
+
+    void insert(const Editor::String& string);
+    void insert_capture(size_t index);
+    void erase();
+    void move_cursors(const BufferCoord& offset);
+
+private:
+    void apply(Modification&& modification) const;
+
+    Editor& m_editor;
+};
+
+}
+
+#endif // editor_hh_INCLUDED
+
diff --git a/src/main.cc b/src/main.cc
index 686dec64..45f38b6a 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -440,7 +440,7 @@ void do_insert(Window& window, IncrementalInserter::Mode mode)
         Key key = get_key();
 
         if (not insert_char(window, inserter, key))
-            return;
+            break;
 
         last_insert_sequence.keys.push_back(key);
         draw_window(window);
@@ -466,7 +466,7 @@ void do_go(Window& window, int count)
         BufferIterator target =
             window.buffer().iterator_at(BufferCoord(count-1, 0));
 
-        window.move_cursor_to(target);
+        window.select(target);
     }
     else
     {
@@ -481,7 +481,7 @@ void do_go(Window& window, int count)
         {
             BufferIterator target =
                 window.buffer().iterator_at(BufferCoord(0,0));
-            window.move_cursor_to(target);
+            window.select(target);
             break;
         }
         case 'l':
@@ -496,7 +496,7 @@ void do_go(Window& window, int count)
         {
             BufferIterator target = window.buffer().iterator_at(
                 BufferCoord(window.buffer().line_count() - 1, 0));
-            window.move_cursor_to(target);
+            window.select(target);
             break;
         }
         }
@@ -926,15 +926,15 @@ void do_select_surrounding(Window& window, int count)
 
 std::unordered_map<Key, std::function<void (Window& window, int count)>> keymap =
 {
-    { { Key::Modifiers::None, 'h' }, [](Window& window, int count) { window.move_selections(DisplayCoord(0, -std::max(count,1))); } },
-    { { Key::Modifiers::None, 'j' }, [](Window& window, int count) { window.move_selections(DisplayCoord( std::max(count,1), 0)); } },
-    { { Key::Modifiers::None, 'k' }, [](Window& window, int count) { window.move_selections(DisplayCoord(-std::max(count,1), 0)); } },
-    { { Key::Modifiers::None, 'l' }, [](Window& window, int count) { window.move_selections(DisplayCoord(0,  std::max(count,1))); } },
-
-    { { Key::Modifiers::None, 'H' }, [](Window& window, int count) { window.move_selections(DisplayCoord(0, -std::max(count,1)), true); } },
-    { { Key::Modifiers::None, 'J' }, [](Window& window, int count) { window.move_selections(DisplayCoord( std::max(count,1), 0), true); } },
-    { { Key::Modifiers::None, 'K' }, [](Window& window, int count) { window.move_selections(DisplayCoord(-std::max(count,1), 0), true); } },
-    { { Key::Modifiers::None, 'L' }, [](Window& window, int count) { window.move_selections(DisplayCoord(0,  std::max(count,1)), true); } },
+    { { Key::Modifiers::None, 'h' }, [](Window& window, int count) { window.move_selections(BufferCoord(0, -std::max(count,1))); } },
+    { { Key::Modifiers::None, 'j' }, [](Window& window, int count) { window.move_selections(BufferCoord( std::max(count,1), 0)); } },
+    { { Key::Modifiers::None, 'k' }, [](Window& window, int count) { window.move_selections(BufferCoord(-std::max(count,1), 0)); } },
+    { { Key::Modifiers::None, 'l' }, [](Window& window, int count) { window.move_selections(BufferCoord(0,  std::max(count,1))); } },
+
+    { { Key::Modifiers::None, 'H' }, [](Window& window, int count) { window.move_selections(BufferCoord(0, -std::max(count,1)), true); } },
+    { { Key::Modifiers::None, 'J' }, [](Window& window, int count) { window.move_selections(BufferCoord( std::max(count,1), 0), true); } },
+    { { Key::Modifiers::None, 'K' }, [](Window& window, int count) { window.move_selections(BufferCoord(-std::max(count,1), 0), true); } },
+    { { Key::Modifiers::None, 'L' }, [](Window& window, int count) { window.move_selections(BufferCoord(0,  std::max(count,1)), true); } },
 
     { { Key::Modifiers::None, 't' }, [](Window& window, int count) { window.select(std::bind(select_to, _1, getch(), count, false)); } },
     { { Key::Modifiers::None, 'f' }, [](Window& window, int count) { window.select(std::bind(select_to, _1, getch(), count, true)); } },
diff --git a/src/selection.cc b/src/selection.cc
new file mode 100644
index 00000000..e772179c
--- /dev/null
+++ b/src/selection.cc
@@ -0,0 +1,120 @@
+#include "selection.hh"
+
+namespace Kakoune
+{
+
+Selection::Selection(const BufferIterator& first, const BufferIterator& last,
+                     const CaptureList& captures)
+    : m_first(first), m_last(last), m_captures(captures)
+{
+   register_with_buffer();
+}
+
+Selection::Selection(const BufferIterator& first, const BufferIterator& last,
+                     CaptureList&& captures)
+    : m_first(first), m_last(last), m_captures(captures)
+{
+   register_with_buffer();
+}
+
+Selection::Selection(const Selection& other)
+    : m_first(other.m_first), m_last(other.m_last),
+      m_captures(other.m_captures)
+{
+   register_with_buffer();
+}
+
+Selection::Selection(Selection&& other)
+    : m_first(other.m_first), m_last(other.m_last),
+      m_captures(other.m_captures)
+{
+   register_with_buffer();
+}
+
+Selection::~Selection()
+{
+   unregister_with_buffer();
+}
+
+Selection& Selection::operator=(const Selection& other)
+{
+   const bool new_buffer = &m_first.buffer() != &other.m_first.buffer();
+   if (new_buffer)
+       unregister_with_buffer();
+
+   m_first    = other.m_first;
+   m_last     = other.m_last;
+   m_captures = other.m_captures;
+
+   if (new_buffer)
+       register_with_buffer();
+
+   return *this;
+}
+
+BufferIterator Selection::begin() const
+{
+    return std::min(m_first, m_last);
+}
+
+BufferIterator Selection::end() const
+{
+    return std::max(m_first, m_last) + 1;
+}
+
+void Selection::merge_with(const Selection& selection)
+{
+    if (m_first <= m_last)
+        m_first = std::min(m_first, selection.m_first);
+    else
+        m_first = std::max(m_first, selection.m_first);
+    m_last = selection.m_last;
+}
+
+BufferString Selection::capture(size_t index) const
+{
+    if (index < m_captures.size())
+        return m_captures[index];
+    return "";
+}
+
+static void update_iterator(const Modification& modification,
+                            BufferIterator& iterator)
+{
+    if (iterator < modification.position)
+        return;
+
+    size_t length = modification.content.length();
+    if (modification.type == Modification::Erase)
+    {
+        // do not move length on the other side of the inequality,
+        // as modification.position + length may be after buffer end
+        if (iterator - length <= modification.position)
+            iterator = modification.position;
+        else
+            iterator -= length;
+    }
+    else
+    {
+        assert(modification.type == Modification::Insert);
+        iterator += length;
+    }
+}
+
+void Selection::on_modification(const Modification& modification)
+{
+    update_iterator(modification, m_first);
+    update_iterator(modification, m_last);
+}
+
+void Selection::register_with_buffer()
+{
+    const_cast<Buffer&>(m_first.buffer()).register_modification_listener(this);
+}
+
+void Selection::unregister_with_buffer()
+{
+    const_cast<Buffer&>(m_first.buffer()).unregister_modification_listener(this);
+}
+
+}
diff --git a/src/selection.hh b/src/selection.hh
new file mode 100644
index 00000000..fc695f9c
--- /dev/null
+++ b/src/selection.hh
@@ -0,0 +1,56 @@
+#ifndef selection_hh_INCLUDED
+#define selection_hh_INCLUDED
+
+#include "buffer.hh"
+
+namespace Kakoune
+{
+
+struct Selection : public ModificationListener
+{
+    typedef std::vector<BufferString> CaptureList;
+
+    Selection(const BufferIterator& first, const BufferIterator& last,
+              const CaptureList& captures = CaptureList());
+
+    Selection(const BufferIterator& first, const BufferIterator& last,
+              CaptureList&& captures);
+
+    Selection(const Selection& other);
+    Selection(Selection&& other);
+
+    ~Selection();
+
+    Selection& operator=(const Selection& other);
+
+    BufferIterator begin() const;
+    BufferIterator end() const;
+
+    const BufferIterator& first() const { return m_first; }
+    const BufferIterator& last()  const { return m_last; }
+
+    void merge_with(const Selection& selection);
+
+    BufferString capture(size_t index) const;
+    const CaptureList& captures() const { return m_captures; }
+
+private:
+    BufferIterator m_first;
+    BufferIterator m_last;
+
+    CaptureList m_captures;
+
+    void on_modification(const Modification& modification);
+
+    void register_with_buffer();
+    void unregister_with_buffer();
+
+    void check_invariant();
+};
+
+typedef std::vector<Selection> SelectionList;
+
+}
+
+#endif // selection_hh_INCLUDED
+
diff --git a/src/window.cc b/src/window.cc
index 52edf331..72ab0578 100644
--- a/src/window.cc
+++ b/src/window.cc
@@ -11,139 +11,11 @@
 namespace Kakoune
 {
 
-Selection::Selection(const BufferIterator& first, const BufferIterator& last,
-                     const CaptureList& captures)
-    : m_first(first), m_last(last), m_captures(captures)
-{
-   register_with_buffer();
-}
-
-Selection::Selection(const BufferIterator& first, const BufferIterator& last,
-                     CaptureList&& captures)
-    : m_first(first), m_last(last), m_captures(captures)
-{
-   register_with_buffer();
-}
-
-Selection::Selection(const Selection& other)
-    : m_first(other.m_first), m_last(other.m_last),
-      m_captures(other.m_captures)
-{
-   register_with_buffer();
-}
-
-Selection::Selection(Selection&& other)
-    : m_first(other.m_first), m_last(other.m_last),
-      m_captures(other.m_captures)
-{
-   register_with_buffer();
-}
-
-Selection::~Selection()
-{
-   unregister_with_buffer();
-}
-
-Selection& Selection::operator=(const Selection& other)
-{
-   const bool new_buffer = &m_first.buffer() != &other.m_first.buffer();
-   if (new_buffer)
-       unregister_with_buffer();
-
-   m_first    = other.m_first;
-   m_last     = other.m_last;
-   m_captures = other.m_captures;
-
-   if (new_buffer)
-       register_with_buffer();
-
-   return *this;
-}
-
-BufferIterator Selection::begin() const
-{
-    return std::min(m_first, m_last);
-}
-
-BufferIterator Selection::end() const
-{
-    return std::max(m_first, m_last) + 1;
-}
-
-void Selection::merge_with(const Selection& selection)
-{
-    if (m_first <= m_last)
-        m_first = std::min(m_first, selection.m_first);
-    else
-        m_first = std::max(m_first, selection.m_first);
-    m_last = selection.m_last;
-}
-
-BufferString Selection::capture(size_t index) const
-{
-    if (index < m_captures.size())
-        return m_captures[index];
-    return "";
-}
-
-static void update_iterator(const Modification& modification,
-                            BufferIterator& iterator)
-{
-    if (iterator < modification.position)
-        return;
-
-    size_t length = modification.content.length();
-    if (modification.type == Modification::Erase)
-    {
-        // do not move length on the other side of the inequality,
-        // as modification.position + length may be after buffer end
-        if (iterator - length <= modification.position)
-            iterator = modification.position;
-        else
-            iterator -= length;
-    }
-    else
-    {
-        assert(modification.type == Modification::Insert);
-        iterator += length;
-    }
-}
-
-void Selection::on_modification(const Modification& modification)
-{
-    update_iterator(modification, m_first);
-    update_iterator(modification, m_last);
-}
-
-void Selection::register_with_buffer()
-{
-    const_cast<Buffer&>(m_first.buffer()).register_modification_listener(this);
-}
-
-void Selection::unregister_with_buffer()
-{
-    const_cast<Buffer&>(m_first.buffer()).unregister_modification_listener(this);
-}
-
-struct scoped_undo_group
-{
-    scoped_undo_group(Buffer& buffer)
-        : m_buffer(buffer) { m_buffer.begin_undo_group(); }
-
-    ~scoped_undo_group()   { m_buffer.end_undo_group(); }
-private:
-    Buffer& m_buffer;
-};
-
 Window::Window(Buffer& buffer)
-    : m_buffer(buffer),
+    : Editor(buffer),
       m_position(0, 0),
-      m_dimensions(0, 0),
-      m_current_inserter(nullptr)
+      m_dimensions(0, 0)
 {
-    m_selections.push_back(SelectionList());
-    selections().push_back(Selection(buffer.begin(), buffer.begin()));
-
     HighlighterRegistry& registry = HighlighterRegistry::instance();
 
     GlobalHooksManager::instance().run_hook("WinCreate", buffer.name(),
@@ -153,42 +25,16 @@ Window::Window(Buffer& buffer)
     registry.add_highlighter_to_window(*this, "highlight_selections", HighlighterParameters());
 }
 
-void Window::check_invariant() const
-{
-    assert(not selections().empty());
-}
-
 DisplayCoord Window::cursor_position() const
 {
-    check_invariant();
     return line_and_column_at(cursor_iterator());
 }
 
 BufferIterator Window::cursor_iterator() const
 {
-    check_invariant();
     return selections().back().last();
 }
 
-void Window::erase()
-{
-    if (m_current_inserter == nullptr)
-    {
-        scoped_undo_group undo_group(m_buffer);
-        erase_noundo();
-    }
-    else
-        erase_noundo();
-}
-
-void Window::erase_noundo()
-{
-    check_invariant();
-    for (auto& sel : selections())
-        m_buffer.modify(Modification::make_erase(sel.begin(), sel.end()));
-    scroll_to_keep_cursor_visible_ifn();
-}
-
 template<typename Iterator>
 static DisplayCoord measure_string(Iterator begin, Iterator end)
 {
@@ -207,76 +53,15 @@ static DisplayCoord measure_string(Iterator begin, Iterator end)
     return result;
 }
 
-static DisplayCoord measure_string(const Window::String& string)
+static DisplayCoord measure_string(const Editor::String& string)
 {
     return measure_string(string.begin(), string.end());
 }
 
-void Window::insert(const String& string)
-{
-    if (m_current_inserter == nullptr)
-    {
-        scoped_undo_group undo_group(m_buffer);
-        insert_noundo(string);
-    }
-    else
-        insert_noundo(string);
-}
-
-void Window::insert_noundo(const String& string)
-{
-    for (auto& sel : selections())
-        m_buffer.modify(Modification::make_insert(sel.begin(), string));
-    scroll_to_keep_cursor_visible_ifn();
-}
-
-void Window::append(const String& string)
-{
-    if (m_current_inserter == nullptr)
-    {
-        scoped_undo_group undo_group(m_buffer);
-        append_noundo(string);
-    }
-    else
-        append_noundo(string);
-}
-
-void Window::append_noundo(const String& string)
-{
-    for (auto& sel : selections())
-        m_buffer.modify(Modification::make_insert(sel.end(), string));
-    scroll_to_keep_cursor_visible_ifn();
-}
-
-void Window::replace(const std::string& string)
-{
-    if (m_current_inserter == nullptr)
-    {
-        scoped_undo_group undo_group(m_buffer);
-        erase_noundo();
-        insert_noundo(string);
-    }
-    else
-    {
-        erase_noundo();
-        insert_noundo(string);
-    }
-}
-
-bool Window::undo()
-{
-    return m_buffer.undo();
-}
-
-bool Window::redo()
-{
-    return m_buffer.redo();
-}
-
 BufferIterator Window::iterator_at(const DisplayCoord& window_pos) const
 {
     if (m_display_buffer.begin() == m_display_buffer.end())
-        return m_buffer.begin();
+        return buffer().begin();
 
     if (DisplayCoord(0,0) <= window_pos)
     {
@@ -290,7 +75,7 @@ BufferIterator Window::iterator_at(const DisplayCoord& window_pos) const
         }
     }
 
-    return m_buffer.iterator_at(m_position + BufferCoord(window_pos));
+    return buffer().iterator_at(m_position + BufferCoord(window_pos));
 }
 
 DisplayCoord Window::line_and_column_at(const BufferIterator& iterator) const
@@ -310,109 +95,19 @@ DisplayCoord Window::line_and_column_at(const BufferIterator& iterator) const
             }
         }
     }
-    BufferCoord coord = m_buffer.line_and_column_at(iterator);
+    BufferCoord coord = buffer().line_and_column_at(iterator);
     return DisplayCoord(coord.line - m_position.line,
                         coord.column - m_position.column);
 }
 
-void Window::clear_selections()
-{
-    check_invariant();
-    BufferIterator pos = selections().back().last();
-
-    if (*pos == '\n' and not pos.is_begin() and *(pos-1) != '\n')
-        --pos;
-
-    Selection sel = Selection(pos, pos);
-    selections().clear();
-    selections().push_back(std::move(sel));
-}
-
-void Window::keep_selection(int index)
-{
-    check_invariant();
-
-    if (index < selections().size())
-    {
-        Selection sel = selections()[index];
-        selections().clear();
-        selections().push_back(std::move(sel));
-    }
-}
-
-void Window::select(const Selector& selector, bool append)
-{
-    check_invariant();
-
-    if (not append)
-    {
-        for (auto& sel : selections())
-            sel = selector(sel.last());
-    }
-    else
-    {
-        for (auto& sel : selections())
-            sel.merge_with(selector(sel.last()));
-    }
-    scroll_to_keep_cursor_visible_ifn();
-}
-
-struct nothing_selected : public runtime_error
-{
-    nothing_selected() : runtime_error("nothing was selected") {}
-};
-
-void Window::multi_select(const MultiSelector& selector)
-{
-    check_invariant();
-
-    SelectionList new_selections;
-    for (auto& sel : selections())
-    {
-        SelectionList selections = selector(sel);
-        std::copy(selections.begin(), selections.end(),
-                  std::back_inserter(new_selections));
-    }
-    if (new_selections.empty())
-        throw nothing_selected();
-
-    selections() = std::move(new_selections);
-    scroll_to_keep_cursor_visible_ifn();
-}
-
-BufferString Window::selection_content() const
-{
-    check_invariant();
-
-    return m_buffer.string(selections().back().begin(),
-                           selections().back().end());
-}
-
-void Window::move_selections(const DisplayCoord& offset, bool append)
-{
-    for (auto& sel : selections())
-    {
-        BufferCoord pos = m_buffer.line_and_column_at(sel.last());
-        BufferIterator last = m_buffer.iterator_at(pos + BufferCoord(offset));
-        sel = Selection(append ? sel.first() : last, last);
-    }
-    scroll_to_keep_cursor_visible_ifn();
-}
-
-void Window::move_cursor_to(const BufferIterator& iterator)
+void Window::update_display_buffer()
 {
-    selections().clear();
-    selections().push_back(Selection(iterator, iterator));
-
     scroll_to_keep_cursor_visible_ifn();
-}
 
-void Window::update_display_buffer()
-{
     m_display_buffer.clear();
 
-    BufferIterator begin = m_buffer.iterator_at(m_position);
-    BufferIterator end = m_buffer.iterator_at(m_position +
+    BufferIterator begin = buffer().iterator_at(m_position);
+    BufferIterator end = buffer().iterator_at(m_position +
                                               BufferCoord(m_dimensions.line, m_dimensions.column))+1;
     if (begin == end)
         return;
@@ -430,8 +125,6 @@ void Window::set_dimensions(const DisplayCoord& dimensions)
 
 void Window::scroll_to_keep_cursor_visible_ifn()
 {
-    check_invariant();
-
     DisplayCoord cursor = line_and_column_at(selections().back().last());
     if (cursor.line < 0)
     {
@@ -454,144 +147,23 @@ void Window::scroll_to_keep_cursor_visible_ifn()
 
 std::string Window::status_line() const
 {
-    BufferCoord cursor = m_buffer.line_and_column_at(selections().back().last());
+    BufferCoord cursor = buffer().line_and_column_at(selections().back().last());
     std::ostringstream oss;
-    oss << m_buffer.name();
-    if (m_buffer.is_modified())
+    oss << buffer().name();
+    if (buffer().is_modified())
         oss << " [+]";
     oss << " -- " << cursor.line+1 << "," << cursor.column+1
         << " -- " << selections().size() << " sel -- ";
-    if (m_current_inserter)
+    if (is_inserting())
         oss << "[Insert]";
     return oss.str();
 }
 
-void Window::add_filter(FilterAndId&& filter)
-{
-    if (m_filters.contains(filter.first))
-        throw id_not_unique(filter.first);
-    m_filters.append(std::forward<FilterAndId>(filter));
-}
-
-void Window::remove_filter(const std::string& id)
-{
-    m_filters.remove(id);
-}
-
-CandidateList Window::complete_filterid(const std::string& prefix,
-                                        size_t cursor_pos)
-{
-    return m_filters.complete_id<str_to_str>(prefix, cursor_pos);
-}
-
-void Window::push_selections()
-{
-    SelectionList current_selections = selections();
-    m_selections.push_back(std::move(current_selections));
-}
-
-void Window::pop_selections()
-{
-    if (m_selections.size() > 1)
-        m_selections.pop_back();
-    else
-        throw runtime_error("no more selections on stack");
-}
-
-IncrementalInserter::IncrementalInserter(Window& window, Mode mode)
-    : m_window(window)
+void Window::on_end_incremental_insert()
 {
-    assert(not m_window.m_current_inserter);
-    m_window.m_current_inserter = this;
-    m_window.check_invariant();
-
-    m_window.m_buffer.begin_undo_group();
-
-    if (mode == Mode::Change)
-        window.erase_noundo();
-
-    for (auto& sel : m_window.selections())
-    {
-        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:
-        case Mode::AppendAtLineEnd:
-            pos = m_window.m_buffer.iterator_at_line_end(sel.end() - 1) - 1;
-            break;
-
-        case Mode::OpenLineAbove:
-        case Mode::InsertAtLineBegin:
-            pos = m_window.m_buffer.iterator_at_line_begin(sel.begin());
-            if (mode == Mode::OpenLineAbove)
-                --pos;
-            break;
-        }
-        sel = Selection(pos, pos, sel.captures());
-
-        if (mode == Mode::OpenLineBelow or mode == Mode::OpenLineAbove)
-            apply(Modification::make_insert(pos, "\n"));
-    }
-}
-
-IncrementalInserter::~IncrementalInserter()
-{
-    move_cursors(DisplayCoord(0, -1));
-
-    m_window.push_selections();
-    m_window.hooks_manager().run_hook("InsertEnd", "", Context(m_window));
-    m_window.pop_selections();
-
-    assert(m_window.m_current_inserter == this);
-    m_window.m_current_inserter = nullptr;
-    m_window.m_buffer.end_undo_group();
-}
-
-void IncrementalInserter::apply(Modification&& modification) const
-{
-    for (auto filter : m_window.m_filters)
-        filter.second(m_window.buffer(), modification);
-    m_window.buffer().modify(std::move(modification));
-}
-
-
-void IncrementalInserter::insert(const Window::String& string)
-{
-    for (auto& sel : m_window.selections())
-        apply(Modification::make_insert(sel.begin(), string));
-}
-
-void IncrementalInserter::insert_capture(size_t index)
-{
-    for (auto& sel : m_window.selections())
-        m_window.m_buffer.modify(Modification::make_insert(sel.begin(),
-                                                           sel.capture(index)));
-    m_window.scroll_to_keep_cursor_visible_ifn();
-}
-
-void IncrementalInserter::erase()
-{
-    for (auto& sel : m_window.selections())
-    {
-        sel = Selection(sel.first() - 1, sel.last() - 1);
-        apply(Modification::make_erase(sel.begin(), sel.end()));
-    }
-
-    m_window.scroll_to_keep_cursor_visible_ifn();
-}
-
-void IncrementalInserter::move_cursors(const DisplayCoord& offset)
-{
-    for (auto& sel : m_window.selections())
-    {
-        DisplayCoord pos = m_window.line_and_column_at(sel.last());
-        BufferIterator it = m_window.iterator_at(pos + offset);
-        sel = Selection(it, it);
-    }
+    push_selections();
+    hooks_manager().run_hook("InsertEnd", "", Context(*this));
+    pop_selections();
 }
 
 }
diff --git a/src/window.hh b/src/window.hh
index e1591d40..ad755388 100644
--- a/src/window.hh
+++ b/src/window.hh
@@ -3,129 +3,45 @@
 
 #include <functional>
 
-#include "buffer.hh"
+#include "editor.hh"
 #include "display_buffer.hh"
 #include "completion.hh"
 #include "highlighter.hh"
 #include "highlighter_group.hh"
-#include "filter.hh"
-#include "idvaluemap.hh"
-#include "hooks_manager.hh"
 
 namespace Kakoune
 {
-
-struct Selection : public ModificationListener
-{
-    typedef std::vector<BufferString> CaptureList;
-
-    Selection(const BufferIterator& first, const BufferIterator& last,
-              const CaptureList& captures = CaptureList());
-
-    Selection(const BufferIterator& first, const BufferIterator& last,
-              CaptureList&& captures);
-
-    Selection(const Selection& other);
-    Selection(Selection&& other);
-
-    ~Selection();
-
-    Selection& operator=(const Selection& other);
-
-    BufferIterator begin() const;
-    BufferIterator end() const;
-
-    const BufferIterator& first() const { return m_first; }
-    const BufferIterator& last()  const { return m_last; }
-
-    void merge_with(const Selection& selection);
-
-    BufferString capture(size_t index) const;
-    const CaptureList& captures() const { return m_captures; }
-
-private:
-    BufferIterator m_first;
-    BufferIterator m_last;
-
-    CaptureList m_captures;
-
-    void on_modification(const Modification& modification);
-
-    void register_with_buffer();
-    void unregister_with_buffer();
-
-    void check_invariant();
-};
-
-typedef std::vector<Selection> SelectionList;
-
-class IncrementalInserter;
 class HighlighterGroup;
 
 // A Window is an editing view onto a Buffer
 //
-// The Window class manage a set of selections and provides means to modify
-// both the selections and the buffer. It also handle the display of the
-// buffer with it's highlighters.
-class Window
+// The Window class is an interactive Editor adding display functionalities
+// to the editing ones already provided by the Editor class.
+// Display can be customized through the use of highlighters handled by
+// the window's HighlighterGroup
+class Window : public Editor
 {
 public:
-    typedef BufferString String;
-    typedef std::function<Selection (const BufferIterator&)> Selector;
-    typedef std::function<SelectionList (const Selection&)>  MultiSelector;
-
-    void erase();
-    void insert(const String& string);
-    void append(const String& string);
-    void replace(const String& string);
-
     const BufferCoord& position() const { return m_position; }
+
     DisplayCoord   cursor_position() const;
     BufferIterator cursor_iterator() const;
 
-    Buffer& buffer() const { return m_buffer; }
-
     BufferIterator iterator_at(const DisplayCoord& window_pos) const;
     DisplayCoord   line_and_column_at(const BufferIterator& iterator) const;
 
-    void move_selections(const DisplayCoord& offset, bool append = false);
-    void move_cursor_to(const BufferIterator& iterator);
-
-    void clear_selections();
-    void keep_selection(int index);
-    void select(const Selector& selector, bool append = false);
-    void multi_select(const MultiSelector& selector);
-    BufferString selection_content() const;
-    const SelectionList& selections() const { return m_selections.back(); }
-
     void set_dimensions(const DisplayCoord& dimensions);
 
     const DisplayBuffer& display_buffer() const { return m_display_buffer; }
 
     void update_display_buffer();
 
-    bool undo();
-    bool redo();
+    const SelectionList& selections() const { return Editor::selections(); }
 
     std::string status_line() const;
 
-    struct id_not_unique : public runtime_error
-    {
-        id_not_unique(const std::string& id)
-            : runtime_error("id not unique: " + id) {}
-    };
-
     HighlighterGroup& highlighters() { return m_highlighters; }
 
-    void add_filter(FilterAndId&& filter);
-    void remove_filter(const std::string& id);
-
-    CandidateList complete_filterid(const std::string& prefix,
-                                    size_t cursor_pos = std::string::npos);
-
-    void push_selections();
-    void pop_selections();
-
     HooksManager& hooks_manager() { return m_hooks_manager; }
 
 private:
@@ -134,58 +50,19 @@ private:
     Window(Buffer& buffer);
     Window(const Window&) = delete;
 
-    void check_invariant() const;
-    void scroll_to_keep_cursor_visible_ifn();
-
-    void erase_noundo();
-    void insert_noundo(const String& string);
-    void append_noundo(const String& string);
-
-    SelectionList& selections() { return m_selections.back(); }
+    void on_end_incremental_insert();
 
-    friend class IncrementalInserter;
-    IncrementalInserter* m_current_inserter;
+    void scroll_to_keep_cursor_visible_ifn();
 
-    Buffer&       m_buffer;
     BufferCoord   m_position;
     DisplayCoord  m_dimensions;
-    std::vector<SelectionList> m_selections;
     DisplayBuffer m_display_buffer;
 
     HighlighterGroup m_highlighters;
-    idvaluemap<std::string, FilterFunc> m_filters;
 
     HooksManager     m_hooks_manager;
 };
 
-class IncrementalInserter
-{
-public:
-    enum class Mode
-    {
-        Insert,
-        Append,
-        Change,
-        InsertAtLineBegin,
-        AppendAtLineEnd,
-        OpenLineBelow,
-        OpenLineAbove
-    };
-
-    IncrementalInserter(Window& window, Mode mode = Mode::Insert);
-    ~IncrementalInserter();
-
-    void insert(const Window::String& string);
-    void insert_capture(size_t index);
-    void erase();
-    void move_cursors(const DisplayCoord& offset);
-
-private:
-    void apply(Modification&& modification) const;
-
-    Window& m_window;
-};
-
 }
 
 #endif // window_hh_INCLUDED