A complete text-mode editor for Linux written in Odin, designed for programmers working on C, C++, Odin and Python (with extra support for Shell, Makefile, JSON and Markdown).

MIT Open Source License

make clean
make
./john              # opens the current directory
./john path/to/dir  # opens a directory (file tree)
./john path/file.c  # opens a file

• Modal-free, Windows-style key bindings (Ctrl+C/X/V/Z/Y/S/O/N/F/H/G/A/Q…).
• File tree on the left, editor area on the right — full mouse support for selection, file ops and resizing the tree column.
• Recursive splits: split panes vertically (Alt+\) or horizontally (Alt+-) any number of times. Focus moves with Alt+H/J/K/L. Drag any divider with the mouse to resize.
• Per-pane scroll & wrap: two panes on the same buffer scroll independently. Alt+Z toggles soft line wrap in the active pane.
• Multiple buffers, switch with Ctrl+P (picker), Ctrl+Tab (cycle), or Alt+1…Alt+9.
• Mouse: click to position the cursor, drag to select, wheel to scroll, click the menu bar / dropdowns / tree rows / dividers.
• Syntax highlighting for C, C++, Odin, Python, Shell, Makefile, JSON and Markdown (headings, lists, blockquotes, bold, italic, code, fenced code blocks, links, images, horizontal rules) via handwritten lexers (see "Tree-sitter note" below).
• Code completion (Ctrl+Space) — keywords, builtins and identifiers scanned from all open buffers and from the working directory plus one level of sub-directories (max 20 dirs total) for .c .cpp .cxx .cc .h .hpp .hh .odin .py .txt .md .markdown .mk and Makefile / makefile / GNUmakefile. The popup is anchored on the line below the cursor and is clamped to screen edges so it shows correctly anywhere, including on the right-most columns.
• Find / Replace (Ctrl+F / Ctrl+H), Go to line (Ctrl+G).
• Undo/Redo with edit history per buffer.
• Menu bar (F10) with File / Edit / View / Window / Help.
• Inline help (F1) listing every key binding — scrollable with ↑/↓/PgUp/PgDn/Home/End and the mouse wheel.
• About dialog (Help → About) with version and feature summary.
• Open Recent (Alt+R) — last 20 files, persisted in ~/.config/john/recent.
• Status bar showing buffer name, dirty state, language, position and size.
• Makefile-aware tab: in Makefile/*.mk buffers Tab inserts a literal tab character instead of spaces (so recipes work).
• Smart Home key (toggles between first non-whitespace and column 0).
• Smart newline indent (continues current line's leading whitespace).
• Selection highlighted with a high-contrast yellow background and bold black foreground — distinct from every syntax color (no "rose"/magenta tones are used anywhere in the palette).
• Word-wise motion with Ctrl+←/→, selection extension with Shift.
• Internal clipboard (Ctrl+C/Ctrl+X/Ctrl+V); when no selection, copy/cut acts on the current line (linewise paste re-inserts above the line). Copy/cut also push the text to the system clipboard via OSC 52, so it works across SSH on terminals that support OSC 52 (xterm, kitty, wezterm, alacritty, foot, iTerm2, recent gnome-terminal; for tmux set set -g set-clipboard on). Pasting from outside JOHN works through bracketed paste: use your terminal's native paste shortcut (Cmd/Ctrl+Shift+V, Shift+Insert, middle-click) and the clipboard contents are inserted at the cursor as a single edit.
• Double-buffered renderer that diffs frames to minimize ANSI output.

Press F1 in the editor for the full list. Highlights:

Everything is a single Odin package editor in this directory — no sub-packages, no cross-package imports, so you can drop new files in here and call any procedure freely.

Every command key in JOHN — every Ctrl+, Alt+, and F-key combination — is configured by a plain text file at ~/.config/john/keys.conf, side-by-side with the recent-files list. The file is created with every standard binding already populated the first time JOHN starts; if you delete it, the next launch writes a fresh copy.

Format (one binding per line):

<key-combo> = <command-name>

• Modifiers (any order, joined with +): ctrl, alt, shift.
• Keys: F1–F12, Tab, Enter, Escape, Backspace, Delete, Insert, Home, End, PageUp, PageDown, Up, Down, Left, Right, Space, or any single printable character (a, /, \, ?…).
• Lines starting with # and blank lines are ignored.

Example overrides:

ctrl+t = find          # use Ctrl+T instead of Ctrl+F to open Find
shift+F3 = find_prev
alt+\ = split_vertical

If the file has a syntax error (unknown modifier, unknown command, missing =, …) JOHN refuses to start and prints exactly where the problem is:

john: /home/me/.config/john/keys.conf:7:12: unknown command 'no_such_action' (run with --list-commands)

Run john --list-commands to print every command name JOHN understands; only those names are valid on the right-hand side of a binding.

C
Cpp
Odin
Python
Markdown
Makefile

JOHN handles UTF-8 throughout. You can edit files containing any codepoint and the cursor moves over whole codepoints, never landing inside a multi-byte character.

• Storage is raw UTF-8 bytes.
• Cursor Left/Right step by codepoints.
• Backspace and Delete remove a whole codepoint.
• Home/End, vertical movement, mouse clicks and the status-bar Col indicator all work in display columns.
• Ctrl+←/Ctrl+→ (word jump) treat any non-ASCII byte as part of a word, so accented identifiers like café and naïve are jumped as single units.
• The dialog boxes (Find, Replace, Open, Goto, etc.) accept and edit UTF-8 input the same way.

Tested with Latin (Café — naïve façade), Greek (αβγδε), Cyrillic (Привет), CJK (日本語テスト中文测试한국어) and emoji (🚀 🎉 ✨).

Note: very wide CJK glyphs and emoji currently render at a single terminal cell width — they appear, just not double-width.

• CJK / wide glyphs are rendered as single-width.
• No project-wide search yet (per-buffer Find/Replace works).

The case-sensitivity setting persists for the rest of the session (and is shared by Find, Find Next/Previous and Replace All). Default at startup is case-insensitive.

Sources: language keywords/builtins, identifiers from all open buffers, identifiers scanned from .c, .cc, .cpp, .cxx, .h, .hpp, .hh, .odin, .py, .md, .markdown and Makefile files in the project (cwd + 1 level of subdirs, up to 20 directories).

• Open recent files: ~/.config/john/recent
• Keybindings: ~/.config/john/keys.conf (auto-created with the defaults; edit freely. See Configurable keybindings above for the format.)
• The recent list is updated automatically every time you open a file.

Best regards,
Joao Carvalho