Mirrors Midnight Commander's
MC src/viewer/actions_cmd.c::mcview_load_next_prev (CK_FileNext
/ CK_FilePrev).
Components:
src/viewer/siblings.rs (new) — pure helper next_or_prev_sibling:
reads current file's parent directory, filters out hidden
files (dot-prefixed), sorts case-insensitive, locates current
by file_name, returns next (direction=+1) or prev (direction=-1)
entry. Returns None at directory boundaries or on I/O error.
6 unit tests cover next/prev/last/first/hidden/no-parent.
src/viewer/mod.rs — Viewer::open_next / Viewer::open_prev
public methods that look up the sibling and reload viewer
state via a private reload_at helper (mirrors MC's
mcview_init/mcview_done pair around mcview_load). Source
errors are converted to std::io::Error so the Result type
matches the existing open() signature.
src/viewer/mod.rs — Ctrl-F / Ctrl-B keybinds in handle_key.
Each delegates to open_next / open_prev.
PLAN.md §15d row 29 marked Done; status bumped to Phase 23.
Tests: 1150 passed (was 1141, +9: 6 siblings module tests +
3 viewer integration tests covering open_next, open_prev,
Ctrl-F/Ctrl-B keybinds). Release binaries build clean.
vasilito
0b0e65a643