wip PyREPL: Add ctrl+up/down for multiline history

Currently, the up/down keys move the cursor in that direction inside the
current code block until it reaches the beginning/end, then it goes to
the previous/next. However, when traversing history with lots of
multiline blocks, this can be a cumbersome process.

This PR introduces the ability to traverse history one block at a time
using the CTRL+Up or CTRL+Down keys.

Originated from https://discuss.python.org/t/pyrepl-add-ctrl-up-down-for-multiline-history-retrieving/107779

Author: edvilme

Lib/_pyrepl/commands.py

@@ -371,6 +371,23 @@ def do(self) -> None:
         for i in range(r.get_arg()):
             r.pos = r.bow()
 
+class up_history(MotionCommand):
+    def do(self) -> None:
+        r = self.reader
+        if r.historyi > 0:
+            r.select_item(r.historyi - 1)
+        else:
+            r.error("start of history")
+            return
+
+class down_history(MotionCommand):
+    def do(self) -> None:
+        r = self.reader
+        if r.historyi < len(r.history):
+            r.select_item(r.historyi + 1)
+        else:
+            r.error("end of history")
+            return
 
 class self_insert(EditCommand):
     def do(self) -> None:

Lib/_pyrepl/keymap.py

@@ -183,7 +183,7 @@ def _parse_single_key_sequence(key: str, s: int) -> tuple[list[str], int]:
     if ctrl:
         if len(ret) == 1:
             ret = chr(ord(ret) & 0x1F)  # curses.ascii.ctrl()
-        elif ret in {"left", "right"}:
+        elif ret in {"left", "right", "up", "down"}:
             ret = f"ctrl {ret}"
         else:
             raise KeySpecError("\\C- followed by invalid key")

Lib/_pyrepl/reader.py

@@ -135,7 +135,9 @@ def make_default_commands() -> dict[CommandName, CommandClass]:
     + [(c, "self-insert") for c in map(chr, range(128, 256)) if c.isalpha()]
     + [
         (r"\<up>", "up"),
+        (r"\C-\<up>", "up_history"),
         (r"\<down>", "down"),
+        (r"\C-\<down>", "down_history"),
         (r"\<left>", "left"),
         (r"\C-\<left>", "backward-word"),
         (r"\<right>", "right"),

Lib/_pyrepl/unix_eventqueue.py

@@ -49,9 +49,13 @@
     # for xterm, gnome-terminal, xfce terminal, etc.
     b'\033[1;5D': 'ctrl left',
     b'\033[1;5C': 'ctrl right',
+    b'\033[1;5A': 'ctrl up',
+    b'\033[1;5B': 'ctrl down',
     # for rxvt
     b'\033Od': 'ctrl left',
     b'\033Oc': 'ctrl right',
+    b'\033Oa': 'ctrl up',
+    b'\033Ob': 'ctrl down',
 }
 
 def get_terminal_keycodes(ti: TermInfo) -> dict[bytes, str]:

Lib/_pyrepl/windows_eventqueue.py

@@ -13,6 +13,8 @@
     b'\x1b[D': 'left',
     b'\x1b[1;5D': 'ctrl left',
     b'\x1b[1;5C': 'ctrl right',
+    b'\x1b[1;5A': 'ctrl up',
+    b'\x1b[1;5B': 'ctrl down',
 
     b'\x1b[H': 'home',
     b'\x1b[F': 'end',