Hemlock (editor)

Hemlock is a free Emacs-style text editor for most POSIX-compliant Unix systems. It follows the tradition of the Lisp Machine editor ZWEI and the ITS/TOPS-20 implementation of Emacs, but differs from many other Emacs variants in that it is written in Common Lisp rather than the usual Emacs Lisp — that is, the Lisp machine and ITS Emacs have largely been rewritten in Common Lisp, borrowing features from later variants of Emacs like XEmacs or GNU Emacs.

Hemlock is integrated with the Common Lisp compiler, interpreter, and development suite CMUCL, though it is possible to use it as a standalone editor, or to use GNU Emacs with CMUCL instead — Hemlock integrates better, but has fewer features and addon programs. One distinctive feature is that Hemlock distinguishes Lisp functions from interactive commands, which are given in a more natural-language-like style derived from the original Lisp machine and TECO Emacs. It is able to display to a terminal, or use the CLX (Common Lisp X Library) for X11.

Hemlock is also the editor of the Clozure CL (formerly OpenMCL) development environment. The editor of LispWorks has been based on Hemlock also.