croatoan

1Introduction

croatoan is a set of bindings to the ncurses terminal library for Common Lisp.

It is inspired by, but not derived from, cl-ncurses and cl-charms.

The API is not yet stable, but the already finished parts are not expected to change much.

It is developed and tested on Ubuntu 20.04 x86_64 and SBCL 2.1.10.

The only supported ncurses version is 6.x --with-abi-version=6. The previous version 5.9 mostly works, but is not actively supported.

If your distribution still ships ncurses --with-abi-version=5, for full compatibility (wide characters, 256 colors and extended mouse support), you will have to manually build ncurses 6.x.

2Goals

Its main goal is to provide a higher-level, lispy/CLOSy interface, whereas the existing bindings clone the cryptic C API.

As of now, the library is in an early, but hopefully usable stage. Ncurses is old and huge, and will take a while to cover completely.

A second goal is to reimplement the extension libraries forms, menu and dialog in Lisp instead of wrapping the C libraries.

A third, distant goal is to provide direct bindings for ANSI escape sequences, so that basic terminal control functions can be used from Lisp on systems without terminfo and ncurses.

3Usage

The library is available in Quicklisp and can be installed with

(ql:quickload "croatoan")

4Systems and packages

Library	System	Package	Short nickname
Higl-level CLOS API	croatoan	croatoan	crt
Low-level ncurses bindings	croatoan-ncurses	ncurses
ANSI X3.64 escape sequences	ansi-escape	ansi-escape	esc

5Documentation

The documentation is currently provided by the docstrings and the commented examples.

6SLIME/Thread support

Since ncurses is not thread-safe, all IO has to occur in the main thread of the REPL running in a terminal.

This makes it difficult to interact with ncurses from the Emacs SLIME REPL which runs in its own thread.

A workaround is to pass all ncurses IO to the main thread via a thread-safe queue. Basic support for this has been implemented.

A tutorial on interacting with ncurses from swank/slime is available in doc/slime.md

7Contributing

You are welcome to contribute and any form of help would be greatly appreciated.

8Contact

Please direct any questions about ncurses, croatoan or other terminal-related Lisp topics, libraries and applications to the following mailing list:

• https://mailman.common-lisp.net/listinfo/croatoan-devel