A provisional interface to GNU-Emacs has been included since version 1.6 of SWI-Prolog. The interface is based on the freely distributed interface delivered with Quintus Prolog. When running Prolog as an inferior process under GNU-Emacs, there is support for finding predicate definitions, completing atoms, finding the locations of compilation-warnings and many more. For details, see the files pl/lisp/README and pl/lisp/swi-prolog.el.