Implement 'cw' and 'r' commands

Author: lkollar

Lib/_pyrepl/reader.py

@@ -186,6 +186,12 @@ def make_default_commands() -> dict[CommandName, type[Command]]:
         (r"d0", "vi-delete-to-bol"),
         (r"d$", "vi-delete-to-eol"),
 
+        # Change commands
+        (r"cw", "vi-change-word"),
+
+        # Replace commands
+        (r"r", "vi-replace-char"),
+
         # Special keys still work in normal mode
         (r"\<left>", "left"),
         (r"\<right>", "right"),

Lib/_pyrepl/vi_commands.py

@@ -146,21 +146,21 @@ def do(self) -> None:
 # Find Commands (f/F/t/T)
 # ============================================================================
 
-def _make_find_char_keymap() -> tuple[tuple[str, str], ...]:
-    """Create a keymap where all printable ASCII maps to vi-find-execute.
+def _make_char_capture_keymap(execute_cmd: str, cancel_cmd: str) -> tuple[tuple[str, str], ...]:
+    """Create a keymap where all printable ASCII maps to execute_cmd.
 
-    Once vi-find-execute is called, it will pop our input translator."""
+    Once execute_cmd is called, it will pop our input translator."""
     entries = []
     for i in range(32, 127):
         if i == 92:  # backslash needs escaping
-            entries.append((r"\\", "vi-find-execute"))
+            entries.append((r"\\", execute_cmd))
         else:
-            entries.append((chr(i), "vi-find-execute"))
-    entries.append((r"\<escape>", "vi-find-cancel"))
+            entries.append((chr(i), execute_cmd))
+    entries.append((r"\<escape>", cancel_cmd))
     return tuple(entries)
 
-
-_find_char_keymap = _make_find_char_keymap()
+_find_char_keymap = _make_char_capture_keymap("vi-find-execute", "vi-find-cancel")
+_replace_char_keymap = _make_char_capture_keymap("vi-replace-execute", "vi-replace-cancel")
 
 
 class vi_find_char(Command):
@@ -327,3 +327,51 @@ def do(self) -> None:
                         new_pos += 1
                     if new_pos < r.pos:
                         r.pos = new_pos
+
+
+# ============================================================================
+# Change Commands
+# ============================================================================
+
+class vi_change_word(KillCommand):
+    """Change from cursor to end of word (cw)."""
+    def do(self) -> None:
+        r = self.reader
+        for _ in range(r.get_arg()):
+            end = r.vi_eow() + 1  # +1 to include last char
+            if end > r.pos:
+                self.kill_range(r.pos, end)
+        r.enter_insert_mode()
+
+
+# ============================================================================
+# Replace Commands
+# ============================================================================
+
+class vi_replace_char(Command):
+    """Replace character under cursor with next typed character (r)."""
+    def do(self) -> None:
+        r = self.reader
+        translator = _input.KeymapTranslator(
+            _replace_char_keymap,
+            invalid_cls="vi-replace-cancel",
+            character_cls="vi-replace-execute"
+        )
+        r.push_input_trans(translator)
+
+class vi_replace_execute(Command):
+    """Execute character replacement with the pressed character."""
+    def do(self) -> None:
+        r = self.reader
+        r.pop_input_trans()
+        pending_char = self.event[-1]
+        if not pending_char or r.pos >= len(r.buffer):
+            return
+        r.buffer[r.pos] = pending_char
+        r.dirty = True
+
+class vi_replace_cancel(Command):
+    """Cancel pending replace operation."""
+    def do(self) -> None:
+        r = self.reader
+        r.pop_input_trans()

Lib/test/test_pyrepl/test_reader.py

@@ -1142,6 +1142,37 @@ def test_find_char_escape_cancels(self):
         reader, _ = self._run_vi(events)
         self.assertEqual(reader.pos, 0)
 
+    def test_change_word(self):
+        events = itertools.chain(
+            code_to_events("hello world"),
+            [
+                Event(evt="key", data="\x1b", raw=bytearray(b"\x1b")),  # ESC
+                Event(evt="key", data="0", raw=bytearray(b"0")),        # BOL
+                Event(evt="key", data="c", raw=bytearray(b"c")),        # change
+                Event(evt="key", data="w", raw=bytearray(b"w")),        # word
+            ],
+            code_to_events("hi"),  # replacement text
+        )
+        reader, _ = self._run_vi(events)
+        self.assertEqual("".join(reader.buffer), "hi world")
+
+    def test_replace_char(self):
+        events = itertools.chain(
+            code_to_events("hello"),
+            [
+                Event(evt="key", data="\x1b", raw=bytearray(b"\x1b")),  # ESC
+                Event(evt="key", data="0", raw=bytearray(b"0")),        # BOL
+                Event(evt="key", data="l", raw=bytearray(b"l")),        # move right to 'e'
+                Event(evt="key", data="l", raw=bytearray(b"l")),        # move right to first 'l'
+                Event(evt="key", data="r", raw=bytearray(b"r")),        # replace
+                Event(evt="key", data="X", raw=bytearray(b"X")),        # replacement char
+            ],
+        )
+        reader, _ = self._run_vi(events)
+        self.assertEqual("".join(reader.buffer), "heXlo")
+        self.assertEqual(reader.pos, 2)  # cursor stays on replaced char
+        self.assertEqual(reader.vi_mode, ViMode.NORMAL)  # stays in normal mode
+
 
 @force_not_colorized_test_class
 class TestHistoricalReaderBindings(TestCase):