Implement repeat last substitution

Author: lieryan

pyvim/commands/commands.py

@@ -710,8 +710,16 @@ def set_scroll_offset(editor, value):
 
 
 def substitute(editor, range_start, range_end, search, replace, flags):
+    if editor.last_substitute_text and replace is None:
+        replace = editor.last_substitute_text
+    else:
+        editor.last_substitute_text = replace
+
     if not search:
         search = editor.application.current_search_state.text
+    else:
+        editor.application.current_search_state.text = search
+
     if flags == 'g':
         transform_callback = lambda s: re.sub(search, replace, s)
     else:

pyvim/editor.py

@@ -129,6 +129,8 @@ def key_pressed(_):
         # Command line previewer.
         self.previewer = CommandPreviewer(self)
 
+        self.last_substitute_text = ''
+
     def load_initial_files(self, locations, in_tab_pages=False, hsplit=False, vsplit=False):
         """
         Load a list of files.

tests/test_substitute.py

@@ -67,6 +67,17 @@ def test_substitute_from_search_history(editor, editor_buffer):
     assert 'Violets are pretty,' in editor_buffer.buffer.text
 
 
+def test_substitute_with_repeat_last_substitution(editor, editor_buffer):
+    given_sample_text(editor_buffer, 'Violet is Violet\n')
+    editor.application.current_search_state.text = 'Lily'
+
+    handle_command(editor, ':s/Violet/Rose')
+    assert 'Rose is Violet' in editor_buffer.buffer.text
+
+    handle_command(editor, ':s')
+    assert 'Rose is Rose' in editor_buffer.buffer.text
+
+
 def test_substitute_flags_empty_flags(editor, editor_buffer):
     given_sample_text(editor_buffer, 'Violet is Violet\n')
     handle_command(editor, ':s/Violet/Rose/')