The mail mode of jedit is intended for composing email.
This document describes the mail mode available with version 3.6/3.0 of jedit.
The Mail Menu and the Buttonbar
The mail mode provides a mode¡specific `Mail' menu and buttonbar each of which provides a `Sign' command which inserts the contents of your ~/.signature file at the bottom of your mail. (The signature is automatically inserted in a fixed¡pitch font, in case you normally use a proportional font and you have ASCII graphics in your .signature, not that I recommend that practise. :-) The `Mail' menu also duplicates the `Done' command found under `File'.
Preferences
By default, the mail mode displays breaks in long lines at character boundaries rather than just at word boundaries; this makes it a little easier to see if you have a line that's too long for email (assuming your window itself isn't too wide and you use a fixed¡pitch font). Also, mail mode will automatically insert newlines for you as you approach the right margin. (There are two different concepts here - whether real newlines are inserted, creating a new line even if you didn't hit the Return key, and how long lines are displayed on the screen. When you're composing email, it's a good idea not to let your lines get any longer than about 72 characters.)
Of course, you can change these preferences on jedit's Mode¡Specific Preferences panel.
See Also
The `mh' Mode
The `exmh' Mode
Evolution
Future Directions
* The mail mode is extremely minimal right now; I'd like to extend it a bit. For instance, it should let you choose among several signature files, and maybe it should know how to reformat paragraphs of quoted text (preceded with `>').
* I'd also like to add MIME support at some point, but I'm not sure how to do that in a generic way, since most mail programs that the mail mode would be used with don't provide access to the headers. (MH does, but there's a separate mode for MH.)