In October of this year, there was a thread on this mailing list regarding
an Emacs mode for GNU APL. As I did not know about this discussion when I
started building my own mode for it, I started working on my own version.
I've been working on this mode for about a month now, and I feel it's
probably ready for other people to use (maybe :-) ).

The source repository for gnu-apl-mode can be found here:
https://github.com/lokedhs/gnu-apl-mode

Please note that it requires GNU APL from their Subversion repository, as
it utilises some features that were not in the latest official release
(1.1).

In this version, I have implemented three different ways of inputting APL
characters:

  - The standard GNU APL keyboard when the "Super" key is held down.
  - A quail-based input method (APL-Z) that allows you to prefix any key
with a period (i.e. ".G" results in ⍒).
  - Mouse-2 on a character in the keyboard help buffer (C-c k).

The key features of this mode includes:

  - Eldoc integration
  - Documentation popup for the symbol under point (by pressing C-c s)
  - Keyboard help (C-c k)
  - Function editor in a separate buffer (by typing ∇function or pressing
C-c f)
  - Coloured error messages

Any comments or criticisms would be greatly appreciated. Also, if people
find this work acceptable, it would be neat to have it included in ELPA
eventually.

Regards,
Elias