ft_select

An interactive terminal list selector built with termcaps: it shows the command-line arguments as a navigable list, lets you select some, and prints the chosen ones back to the shell — meant for backtick use:

set files = `./ft_select *.c`
rm `./ft_select ~/Downloads/*`

Build & run

make           # builds the bundled libft, then ft_select
./ft_select a b c d e

The libft submodule is at vendor/libft and is built automatically. By default the Makefile builds it with SAFE=1 (libc allocator) so valgrind can verify every allocation; make SAFE= switches to libft's in-house ft_malloc.

Controls

Key	Action
Arrows ←↑↓→	move the cursor (circular, across columns)
Space	select / deselect the current item, then advance
Enter	print the selected items (argv order, space-separated) and exit
Esc	quit, print nothing
Backspace / Delete	remove the current item from the list (empty list ⇒ quit like Esc)
printable keys	dynamic search — jump the cursor to the next matching item
Ctrl-Z / fg	suspend / resume (terminal restored while suspended)
window resize	reflow into multiple columns, keeping selections

Display: selected = inverse video, cursor = underline, both compose; filename items are colorized by extension.

Design

• Data model — items are a libft t_vec<char *> (each ft_strdup'd from argv); a parallel t_vec<unsigned char> holds the selection flags; the whole frame is rendered into a reused t_vec<char>. The only global is one volatile sig_atomic_t g_signo; everything else is threaded through t_app *.
• Pure/terminal split — all the logic (arg ingest, column geometry, navigation, select/delete, output formatting) lives in pure, terminal-free functions (args/layout/navigate/select_ops/output/search/color.c) declared in include/ft_select.h. This is the unit-test seam: it lets ~1900 cases run headless. The terminal code (term/input/render/signals/loop.c) is exercised end-to-end under a pseudo-terminal.
• Column layout — ls-style column-major packing: one column when the rows fit, otherwise ceil(n / rows) columns clamped to what the width allows; a bijection maps each item index ↔ (row, col). Every divisor is floored at 1, so a 1×1 or absurd window never divides by zero — it just draws nothing until the window grows back.
• Rendering — the entire frame (cursor moves + attributes + text) is assembled into one buffer and emitted with a single write, so there is no flicker and no per-cell syscall storm (the manual equivalent of double-buffering).
• Always restore the terminal — raw mode is entered with tcsetattr, and a restore (show cursor + reset attrs + tcsetattr back to the saved termios) runs on every exit path: Enter, Esc, delete-to-empty, init failure, and from the signal handlers (SIGINT/SIGTERM free the heap and exit; SIGTSTP restores cooked mode before the stop).

Termcap = libft's own (no -ltermcap)

This project uses the termcap implementation inside the bundled libft (tgetent/tgetstr/tgetnum/tgetflag/tgoto/tputs), not the system -ltermcap. Consequences: a single self-contained build, no duplicate-symbol clash, and the caps come from $TERMCAP / libft's built-in fallback (which provides cl cm ce so us ue me for xterm). To switch to the system library instead, see the make TERMCAP=system contingency note in the defense section.

Bonuses

All four: dynamic search (type to jump), clean exit (erase the drawing and leave the prompt on the next line), extension colorization (filenames colored like ls), and horizontal column scroll (columns follow the cursor when the window is too narrow).

Testing

make test    # ~1900 distinct pure-logic cases (invariant/property style) — µtest framework
make e2e     # 18 forkpty end-to-end scenarios against the real binary
make leaks   # valgrind leak + fd matrix across 15 contexts (real libc-allocator check)
make norm    # norminette (src + include): clean

The tests run on a small custom gtest-style C framework (tests/framework/): TEST/ASSERT_*/EXPECT_*/SUBCASE, fork-per-test isolation (so a crash or hang is reported, not fatal to the suite), and forkpty helpers. The leak matrix proves real allocation balance (definitely+indirectly lost == 0), no leaked file descriptor, and no invalid access — including under SIGINT, SIGTSTP, resize storms, delete-to-empty, thousands of args, missing/unknown $TERM, and redirected stdout.

Defense notes

• Why libft termcap? The subject mandates termcaps; the bundled libft already implements the full termcap API, so the project links one archive and stays self-contained. It is functionally complete here (fallback caps for xterm). Contingency: make TERMCAP=system (documented) swaps to -ltermcap with header isolation if a corrector requires the system library.
• Allocator (SAFE=1). Built with libft's libc-allocator mode so "no leaks" is genuinely valgrind-verifiable (Memcheck sees every malloc/free). libft's mmap-backed ft_malloc is still available via make SAFE=.
• Ctrl-Z without raise/kill. Those are not in the allowed function list, so the SIGTSTP handler restores cooked mode and re-arms the default disposition (signal(SIGTSTP, SIG_DFL)); the kernel then performs the real job-control stop. The terminal is always left sane while suspended, using only allowed calls.
• Terminal restore is guaranteed even on signal: proved out-of-band by the e2e harness reading the pty's termios (ICANON/ECHO restored) after the child dies.