led - Larry's Editor for Linux/Unix Terminal (1.0.6)

Dedicated to Neal Stephenson's vision of paper-like data safety.

What Works

• Data safety: unlimited undo/redo (10k cap), auto-save with versioned backups, crash recovery. Rejects files >10MB or with null bytes; validates line length.
• Editing: insert, newline, backspace/delete, tabs (spaces or \t), word wrap (F3), selection, clipboard (Ctrl+A/C/X/V), regex search (Ctrl+/) and replace (Ctrl+R), syntax highlighting (C/C++ nesting, pre-parsed, per-line cache).
• Display: F2 line numbers, F3 word wrap, F4 border toggle (see below), status bar (version/time/position/key-meter show_key_meter), Unicode/Cyrillic.
• Incremental rendering: cursor moves repaint only status line, single-line edits repaint only that row (75x less output); view_decide() + nesting cache.
• Border handling: text in derwin(stdscr, LINES-2,COLS-2,1,1) (border on) or derwin(stdscr, LINES-1,COLS,0,0) (border off); border only on FULL repaint. Paste-time border_filter_dup() strips | + - │ ─ ┌ ┐ └ ┘ ├ ┤ ┬ ┴ ┼ per line and drops pure ┌──┐ lines — replaces tr -d.
• Config: ~/.config/led/colorization.conf (colors, reserved_words, paired_keywords, syntax_extensions, show_key_meter, show_border), env LED_NO_BORDER=1 / LED_SHOW_BORDER.
• Tests: 133 tests (buffer, undo, clipboard, autosave, view truncate, change tracking, view_decide). ./led -t on your machine.

What Fails

• Large files: whole file loaded into memory, no lazy/mmap. Past about 30000 lines it hogs the system and you may have to kill the process. Split huge files first.
• Long lines: truncates past 10k characters; those lines skip highlighting and use basic rendering.
• Hardcoded limits: file size and line length are not configurable yet.
• Language support: highlighting and parsing are built for C/C++; other languages may be incomplete. Turn highlighting off in config if a file fights you.
• Error handling: not fully standardized across modules.
• No per-buffer undo persistence across sessions.
• No fuzzing / empty-file edge coverage yet.
• Input sanitization: no directory-traversal check beyond is_filename_safe.
• Terminal: xterm block-select still copies screen cells — use F4 off or filter; no OSC 52 system clipboard.

Bugs: size and type (file, head sample), or a gdb ./led backtrace, at https://github.com/refgift/led/issues

Dependencies

C compiler, make (gmake on Unix), libncursesw, glibc regex.

Build / Install / Test

make              # builds ./led
make install      # installs to /usr/local/bin
make doc          # installs led.1
./led file.c
./led -t          # test mode (stderr, no curses) — also LED_TEST=1 ./led
man led           # after make doc

Keybindings

Keys	Action
Arrows, Home/End (×2 top/bottom), PgUp/PgDn	Navigation
Printable, Enter, Backspace/Delete, Tab	Insert / delete
Ctrl+Z / Ctrl+Y	Undo / Redo
Ctrl+S / Ctrl+Q	Save / Quit
Ctrl+A / Ctrl+C / Ctrl+X / Ctrl+V	Select all / Copy / Cut / Paste (paste is border-filtered)
Ctrl+/ / Ctrl+R	Search / Replace (regex, 100-char limit)
F2	Line numbers
F3	Word wrap
F4	Border on/off (subwindow inset vs full-width; pasted │ stripped)

Configuration

~/.config/led/colorization.conf — key=value, # comments, created on first run.

Colors (BLACK,RED,GREEN,YELLOW,BLUE,MAGENTA,CYAN,WHITE): normal_fg/bg, selection_fg/bg, semicolon_fg/bg, meta_level1..4_fg/bg, reserved_words_fg/bg.

Display/Border: show_border=0 (default off, 1 shows box). Toggled by F4.

Other: syntax_extensions=.c,.h,.cpp, reserved_words=..., paired_keywords=if-then,begin-end,(,), tab_width=8, spaces_for_tab=0, show_key_meter=1.

Example:

normal_fg=WHITE
normal_bg=BLACK
selection_fg=CYAN
selection_bg=BLACK
show_key_meter=1
show_border=0
syntax_extensions=.c,.h,.cpp