mle

mle is a small, flexible, terminal-based text editor written in C.

Runs on Linux, Windows (cygwin or WSL), FreeBSD, and macOS.

Demos

Aims

Keep codebase small and hackable
Minimize build-time and run-time dependencies
Make extensible and configurable
Favor simplicity over portability
Use shell commands to enhance functionality (e.g., grep, tree)

Features

Small codebase (<10k sloc)
Full UTF-8 support
Syntax highlighting
Stackable key maps (modes)
Extensible via Lua
Scriptable rc file
Key macros
Multiple splittable windows
Regex search and replace
Large file support
Incremental search
Linear undo and redo
Multiple cursors
Auto indent
Headless mode
Navigation via ctags
Movement via less
Fuzzy file search via fzf
File browsing via tree
File grep via grep
String manip via perl

Building

$ sudo apt install git build-essential libtool automake # or equivalent
$
$ git clone --recursive https://github.com/adsr/mle.git
$ cd mle
$ make mle_vendor=1

To build a completely static binary, try make mle_vendor=1 mle_static=1.

You can also run plain make to link against system libraries instead of vendor/. Note this requires the following packages to be installed:

uthash-dev
liblua5.3-dev
libpcre3-dev

To install to /usr/local/bin:

$ make install

To install to a custom directory, supply prefix, e.g.:

$ make install prefix=/usr # /usr/bin/mle

Installing from a repo

mle may be available to install via your system's package manager.

# snap install mle  # all major Linux distros
# apt install mle   # Ubuntu and Debian-based distros
# pkg install mle   # FreeBSD
# yay -S mle        # Arch (via AUR)
# nix-env -i mle    # NixOS (via nixpkgs)
# apk add mle       # Alpine
# xbps-install mle  # Void

Basic usage

$ mle               # Open blank buffer
$ mle one.c         # Edit one.c
$ mle one.c:100     # Edit one.c at line 100
$ mle one.c two.c   # Edit one.c and two.c
$ mle -h            # Show command line help

The default key bindings are intuitive. Input text as normal, use directional keys to move around, use Ctrl-S to save, Ctrl-O to open, Ctrl-X to exit.

Press F2 for full help.

Advanced usage: mlerc

mle is customized via command line options. Run mle -h to view all cli options.

To set default options, make an rc file named ~/.mlerc (or /etc/mlerc). The contents of the rc file are any number of cli options separated by newlines. Lines that begin with a semi-colon are interpretted as comments.

If ~/.mlerc is executable, mle executes it and interprets the resulting stdout as described above. For example, consider the following snippet from an executable ~/.mlerc bash(1) script:

# Define 'test' kmap
echo '-Ktest,,1'

# M-q: replace grep with git grep if `.git` exists
if [ -d ".git" ]; then
  echo '-kcmd_grep,M-q,git grep --color=never -P -i -I -n %s 2>/dev/null'
fi

# Set default kmap
echo '-n test'

This overrides the built-in grep command with git grep if .git exists in the current working directory.

Shell command integration

The following programs will enable or enhance certain features of mle if they exist in PATH.

bash (tab completion)
fzf (fuzzy file search)
grep (file grep)
less (less integration)
perl (perl 1-liners)
readtags (ctags integration)
tree (file browsing)

Arbitrary shell commands can also be run via cmd_shell (M-e by default). If any text is selected, it is sent to stdin of the command. Any resulting stdout is inserted into the text buffer.

Advanced usage: Headless mode

mle provides support for non-interactive editing which may be useful for using the editor as a regular command line tool. In headless mode, mle reads stdin into a buffer, applies a startup macro if specified, and then writes the buffer contents to stdout. For example:

$ echo -n hello | mle -M 'test C-e space w o r l d enter' -p test
hello world

If stdin is a pipe, mle goes into headless mode automatically. Headless mode can be explicitly enabled or disabled with the -H option.

If stdin is a pipe and headless mode is disabled via -H0, mle reads stdin into a new buffer and then runs as normal in interactive mode.

Advanced usage: Scripting

mle is extensible via the Lua programming language. Scripts are loaded via the -x cli option. Commands registered by scripts can be mapped to keys as normal via -k. See uscript.lua for a simple example.

There is also a wren branch with Wren scripting support. That work is on pause.

Known bugs

Multi-line style rules don't work properly when overlapped/staggered.

Forks

eon - mouse support and Notepad-like selections
turbo-mle - Turbo Vision port

Acknowledgments

mle makes extensive use of the following libraries.

uthash for hash maps and linked lists
termbox2 for TUI
PCRE for syntax highlighting and search

blackPantherOS/mle

mle