Hi, Jürgen,
On 18/07/18 05:36, Juergen Sauermann wrote:
Hi Chris,
thank you for contributing this. I have added a link on our community page
http://www.gnu.org/software/apl/Community.html.
I believe the function would be even more useful it could create or modify
an APL function in a running workspace rather than writing the
function to a file.
It already does that--even in the current version, once the editor
closes and the system() call that started it returns, the file is read
and fixed back into the workspace. (I guess I need to make that clearer
in the README.)
But version 2.0 takes it even farther--I fork()/exec() to start the
editor, along with a fork()-ed inotify waitspin that listens for changes
in the working file. When the editor writes to the file, the change is
caught and the function is fixed into the workspace, but the editor
stays open until you explicitly kill it. The effects of this are that
APL keeps running even while the editor is open--you can real-time run
the function after every save and see if it's doing the right thing--and
you can have any number of editor sessions running simultaneously. (I
don't know how useful that will be, but it was easy to make happen...)
All this works even now, but somewhere in all these spawned processes I
seem to be firing off a wild signal and not catching it so it winds up
interrupting the main APL readline loop resulting in either a null input
or a spurious ctrl-d. I'm working on that now.
--Chris
/// Jürgen
On 07/15/2018 10:47 PM, Chris Moller wrote:
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.")
