Modes are the heart of (Pce)Emacs. Modes define dedicated editing support for a particular kind of (source) text. For our purpose we want Prolog mode. There are various ways to make PceEmacs use Prolog mode for a file.
- Using the proper extension
If the file ends in
.plor the selected alternative (e.g.
.pro) extension, Prolog mode is selected.
If the file is a Prolog Script file, starting with the line
#!/path/to/swiploptions, Prolog mode is selected regardless of the extension.
-*- Prolog -*-
If the above sequence appears in the first line of the file (inside a Prolog comment) Prolog mode is selected.
- Explicit selection
Finally, using File/Mode/Prolog you can switch to Prolog mode explicitly.