[ruby/reline] Implement changing editing mode

(https://github.com/ruby/reline/pull/681)

https://github.com/ruby/reline/commit/501b9a6c5f

lib/reline/line_editor.rb

@@ -2630,4 +2630,12 @@ class Reline::LineEditor
     @mark_pointer = new_pointer
   end
   alias_method :exchange_point_and_mark, :em_exchange_mark
+
+  private def emacs_editing_mode(key)
+    @config.editing_mode = :emacs
+  end
+
+  private def vi_editing_mode(key)
+    @config.editing_mode = :vi_insert
+  end
 end

test/reline/test_key_actor_emacs.rb

@@ -1436,4 +1436,9 @@ class Reline::KeyActor::Emacs::Test < Reline::TestCase
     input_keys("\C-f\C-u", false)
     assert_line_around_cursor('', '')
   end
+
+  def test_vi_editing_mode
+    @line_editor.__send__(:vi_editing_mode, nil)
+    assert(@config.editing_mode_is?(:vi_insert))
+  end
 end

test/reline/test_key_actor_vi.rb

@@ -911,4 +911,9 @@ class Reline::KeyActor::ViInsert::Test < Reline::TestCase
       input_keys("test = { foo: bar }\C-[BBBldt}b")
     end
   end
+
+  def test_emacs_editing_mode
+    @line_editor.__send__(:emacs_editing_mode, nil)
+    assert(@config.editing_mode_is?(:emacs))
+  end
 end