Per-terminal optimized `watch`-like xonsh alias that
runs an arbitrary callable alias in a loop inside the
alt-screen buffer with flicker-free repaint. Supersedes
the inline `acli.ptree` polling .xsh snippet (removed
from `_ptree` docstr in favor of
`acli.watch acli.ptree pytest`).
Deats,
- alt-screen entry/exit (`\033[?1049h/l`) + cursor-hide
(`\033[?25l/h`) wrapped in try/finally so Ctrl-C always
returns to a pristine shell.
- per-frame draw uses cursor-home (`\033[H`) + per-line
EL (`\033[K` before each `\n`) + post-draw erase-down
(`\033[J`) → stale tail chars from a longer prior
frame are obvi cleared; no full-screen flash.
- SIGWINCH-aware: terminal resize sets a flag, next
frame does a full clear (`\033[H\033[2J`) instead of
the cheap cursor-home path.
- Ctrl-C handling: install `signal.default_int_handler`
so `KeyboardInterrupt` lands cleanly; prior handler
restored on exit.
- Output capture: redirect the alias's stdout to
`StringIO` per frame so we can post-process the EL
fix. Aliases writing directly to `sys.stdout.buffer`
/ `os.write(1)` bypass capture — EL-fix won't apply
but loop still works.
- Alias unwrap: xonsh stores callables as either a bare
callable OR `[fn, *preset_args]`. Both forms handled;
subprocess-style aliases rejected w/ a friendly err
msg.
- `argparse` w/ `-n`/`--interval` (default 0.3s); rest
of argv forwarded as alias args.
- Reg `'acli.watch': watch` in `_TCLI_ALIASES`.
Other,
- Tn `_ptree` `args: list[str]` param.
- Mod-header `Provides:` block updated w/ `acli.watch`
entry.
- Top-level imports: `os`, `sys`, `signal`, `time`,
`typing.Callable`.
(this patch was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code
Gud Boi
bb239e847f