Python 3.13.0b1 REPL does not travel words when pressing Ctrl+← or Ctrl+→

[hroncok]

Bug report

Bug description:

When I type this to older Python REPLs:

>>> text = "I can travel the words."

And I press Ctrl+←, my cursor moves in front of w. I can press Ctrl+← again to go in front of the t etc. I can then press Ctrl+→ to travel the words in the other direction. My bash behaves the same. Again, I don't know if this is Fedora's configuration of readline, or the default.

In Python 3.13.0b1 REPL, this no longer works. Pressing Ctrl+← or Ctrl+→ seemingly does nothing.

CPython versions tested on:

3.13

Operating systems tested on:

Linux

Linked PRs

• gh-119248

[tomasr8]

It seems that Ctrl+← is converted into ctrl left which is treated as an invalid character (same for Ctrl+→). Not sure how to represent this key combination in the keymap but this dirty hack makes it work:

diff --git a/Lib/_pyrepl/input.py b/Lib/_pyrepl/input.py
index 21c24eb5cd..0b804e9252 100644
--- a/Lib/_pyrepl/input.py
+++ b/Lib/_pyrepl/input.py
@@ -61,6 +61,8 @@ def empty(self) -> bool:
 
 class KeymapTranslator(InputTranslator):
     def __init__(self, keymap, verbose=False, invalid_cls=None, character_cls=None):
         self.verbose = verbose
         from .keymap import compile_keymap, parse_keys
 
@@ -73,7 +75,14 @@ def __init__(self, keymap, verbose=False, invalid_cls=None, character_cls=None):
             d[keyseq] = command
         if self.verbose:
             print(d)
         self.k = self.ck = compile_keymap(d, ())
+        self.k['ctrl left'] = 'backward-word'
+        self.k['ctrl right'] = 'forward-word'
         self.results = deque()

[ambv]

See https://github.com/python/cpython/issues/119034#issuecomment-2121142576 for a list of things we will be implementing as additional keyboard mappings.