After battling for decades with the ancient nabla editor, I finally did
something I should have done years ago and write a simple native
function that let's you use emacs or vi from inside an APL session.
It's not even close to Elias Mårtenson's cool emacs APL mode--it's just
a quick thing to bring up a friendlier editor. It's alpha-level
code--if it melts your computer, it's not my fault--and there are a few
things on the TODO list, but I thought I'd put it out there and get some
feedback if anyone's interested.
Here's the README:
edif is a GNU APL native function that allows the use of external
editors
from within an APL session.
Usage:
edif 'function_name'
This will open an editor, typically vi or emacs, containing the present
definition of the specified function, or, if the function doesn't exist,
a boilerplate function header consisting of the function name.
After saving
the edited definition and exiting the editor, the function will
appear in
the APL workspace. While the editor is open, APL is suspended.
edif will look for the environment variable EDIF and will use the string
specified by that variable as the command line to invoke the chosen
editor.
For example:
export EDIF="emacs --geometry=40x20 -background '#ffffcc' -font
'DejaVu Sans Mono-10'"
will invoke emacs with a fairly small window, a light yellow
background, and
using the DejaVu Sans Mono-10 font. (That's also the default if no EDIF
variable is found.)
edif has only been tested with emacs and vi.
Future work may also allow edif to edit APL variables and operators,
but no
guarantees I'll ever get around to it.
edif may be included in the workspace with:
'libedif.so' ⎕fx 'edif'
Implimentation note:
edif works by storing an editable version of the specified function in:
/var/run/user/<uid>/<pid>/<name>.apl
where <uid> is the user's userid, <pid> is the process id of the APL
session, and <name> is the function name. This allows multiple users
each to have multiple simultaneous APL sessions with workspaces with
identical names. No locking is done by edif and I've no idea if APL
itself has any protection against a writable workspace being open in
multiple simultaneous sessions, but it opens up the possibility that
you can hose the workspace. So while, as far as edif is concerned
you can have multiple simultaneous sessions aimed at the same lib0
workspace, you probably shouldn't do it.
Also, I've no idea if Windows or any Linux distribution other than
Fedora has a /var directory, so using this directory may be
non-portable.
So far as I can tell, edif doesn't interfere with Elias Mårtenson's
emacs APL mode, but I haven't thoroughly tested that.
It's at https://github.com/ChrisMoller/edif
(BTW, "edif" is short for "editor interface.")
