If it fails, edit/1
uses its internal defaults, which are defined by the Prolog flag editor
and/or the environment variable
EDITOR
. The following rules apply. If the Prolog flag editor
is of the format $
<name>, the editor is
determined by the environment variable <name>. Else, if
this flag is pce_emacs
or built_in
and XPCE is loaded or can be loaded, the built-in Emacs clone
is used. Else, if the environment EDITOR
is set, this
editor is used. Finally,
vi is used as default on Unix systems and notepad on
Windows.
See the default user preferences file customize/init.pl
for examples.