Implement em_set_mark and em_exchange_mark

lib/reline/ansi.rb

@@ -6,7 +6,9 @@ class Reline::ANSI
     [27, 91, 68] => :ed_prev_char,        # ←
     [27, 91, 51, 126] => :key_delete,     # Del
     [27, 91, 49, 126] => :ed_move_to_beg, # Home
-    [27, 91, 52, 126] => :ed_move_to_end, # End
+    [27, 91, 68] => :ed_prev_char,        # ←
+    [27, 32] => :em_set_mark,             # M-<space>
+    [24, 24] => :em_exchange_mark,        # C-x C-x TODO also add Windows
   }
 
   @@input = STDIN

lib/reline/line_editor.rb

@@ -138,6 +138,7 @@ class Reline::LineEditor
 
   def reset_variables(prompt = '', encoding = Encoding.default_external)
     @prompt = prompt
+    @mark_pointer = nil
     @encoding = encoding
     @is_multiline = false
     @finished = false
@@ -1941,4 +1942,20 @@ class Reline::LineEditor
     arg -= 1
     vi_join_lines(key, arg: arg) if arg > 0
   end
+
+  private def em_set_mark(key)
+    @mark_pointer = [@byte_pointer, @line_index]
+  end
+  alias_method :set_mark, :em_set_mark
+
+  private def em_exchange_mark(key)
+    new_pointer = [@byte_pointer, @line_index]
+    @previous_line_index = @line_index
+    @byte_pointer, @line_index = @mark_pointer
+    @byte_pointer, @line_index = @mark_pointer
+    @cursor = calculate_width(@line.byteslice(0, @byte_pointer))
+    @cursor_max = calculate_width(@line)
+    @mark_pointer = new_pointer
+  end
+  alias_method :exchange_point_and_mark, :em_exchange_mark
 end

test/reline/helper.rb

@@ -44,6 +44,10 @@ class Reline::TestCase < Test::Unit::TestCase
     retry
   end
 
+  def input_key_by_symbol(input)
+    @line_editor.input_key(Reline::Key.new(input, input, false))
+  end
+
   def input_keys(input, convert = true)
     input = convert_str(input) if convert
     input.chars.each do |c|

test/reline/test_key_actor_emacs.rb

@@ -1403,6 +1403,38 @@ class Reline::KeyActor::Emacs::Test < Reline::TestCase
     @config.history_size = history_size
   end
 
+  def test_em_set_mark_and_em_exchange_mark
+    input_keys('aaa bbb ccc ddd')
+    assert_byte_pointer_size('aaa bbb ccc ddd')
+    assert_cursor(15)
+    assert_cursor_max(15)
+    assert_line('aaa bbb ccc ddd')
+    input_keys("\C-a\M-F\M-F", false)
+    assert_byte_pointer_size('aaa bbb')
+    assert_cursor(7)
+    assert_cursor_max(15)
+    assert_line('aaa bbb ccc ddd')
+    assert_equal(nil, @line_editor.instance_variable_get(:@mark_pointer))
+    input_keys("\x00", false) # C-Space
+    assert_byte_pointer_size('aaa bbb')
+    assert_cursor(7)
+    assert_cursor_max(15)
+    assert_line('aaa bbb ccc ddd')
+    assert_equal([7, 0], @line_editor.instance_variable_get(:@mark_pointer))
+    input_keys("\C-a", false)
+    assert_byte_pointer_size('')
+    assert_cursor(0)
+    assert_cursor_max(15)
+    assert_line('aaa bbb ccc ddd')
+    assert_equal([7, 0], @line_editor.instance_variable_get(:@mark_pointer))
+    input_key_by_symbol(:em_exchange_mark)
+    assert_byte_pointer_size('aaa bbb')
+    assert_cursor(7)
+    assert_cursor_max(15)
+    assert_line('aaa bbb ccc ddd')
+    assert_equal([0, 0], @line_editor.instance_variable_get(:@mark_pointer))
+  end
+
 =begin # TODO: move KeyStroke instance from Reline to LineEditor
   def test_key_delete
     input_keys('ab')