Re: Asynchronous blocks for everything (was Re: [BUG] Unexpected result when evaluating python src block asynchronously [9.7-pre (release_9.6.17-1131-gc9ed03.dirty @ /home/yantar92/.emacs.d/straight/build/org/)])

[Ihor Radchenko]

Bruno Barbier <brubar.cs@gmail.com> writes:

> Hi Matt, Jack, Ihor,
>
> Sorry for the late reply.  Cleaning the code took me longer than
> expected.

Thanks for the code!
It is a lot more that I expected.
I have many questions ;)

> The new API itself is more about how to wait for and display one block
> result.  So, it's not really aware of sessions.

I think that it is important to think about sessions. For non-sessions,
we may execute the code in parallel, disregarding already running
execution. In contrast, for sessions, we need to maintain some queue and
wait until previous execution finishes before running next (if multiple
session blocks are executed in quick succession).

It may also be necessary to provide an UI listing the queued and running
execution. Users should be able to stop "stale" processes if they are
defunc (consider infinite loop).

>> Also interesting, I think it's worth exploring/testing this overlay idea
>> out. Does that mean that output is asynchronously printing into the Org
>> buffer? It sounds cool but I wonder if it might cause problems while
>> trying to edit another part of the buffer.
>
> Currently, I've limited the progress feedback to fit on one line to
> avoid anoying vertical display jumps.  When the computation is
> successful, the result is inserted as usual, and, that may be annoying;
> when it updates a previous result of the same height, it's ok.  Else, we
> could fold it to stay on one line too (using the overlay), until the
> user explicitly request to see it.

Let's not worry about "jumps" yet. It is a minor issue that can be
easily solved.

What is more important is when users, for example, remove the whole
subtree containing the place where the execution result is to be
inserted. Or when users perform edits at or around that place where the
result is to be inserted. Or consider subtree with pending result
refiled elsewhere (different file or different place in the same file);
or archived.

Or consider user running an src block, quickly editing it, and then
running again. What should we do then? Should we stop the first running
process?

> So, here we go.  You'll find attach a set of patchs.  It works for me with
> Emacsc 30.50 and 9.7-pre (from today).

I have several general questions:

- what if append/prepend to result asynchronously?
- what if we replace the result, call async evaluation two times, and they 
arrive in opposite order (first called is calculated after the second)?
- on failure, Org babel sometimes uses ~org-babel-eval-error-notify~. How will 
it interact with asynchronous evaluation? What if we have multiple 
simultaneously arriving error notifications?
  Example: try running
  #+begin_src bash
  idontexist
  #+end_src

> I didn't check yet that the code and the commits follow all the
> guidelines.  This is just a preliminary version for feedbacks.
> Corrections/critiques are welcome, but don't check the details until I
> check them myself.
> So, I decided to rewrite the whole thing, taking code from the
> synchronous case (following `org-babel-python-evaluate-session').  I
> also created a package that contains all the functions that should be
> reusable for any language.  The patch [1] adds some generic functions to
> help dealing with asynchronicity (process, comint, etc.). The patch [2]
> shows a new possible way to execute python code blocks, both
> synchronously and asynchronously, with or without sessions.  You should
> just need to open [3] and follow what's written there, and execute the
> existing bash and python code blocks.

Note that we already have a WIP an asynchronous API in the works.
Check out `org-async-call' in
https://code.tecosaur.net/tec/org-mode/src/branch/dev/lisp/org-macs.el#L377
If possible, we should reuse it.

-- 
Ihor Radchenko // yantar92,
Org mode contributor,
Learn more about Org mode at <https://orgmode.org/>.
Support Org development at <https://liberapay.com/org-mode>,
or support my work at <https://liberapay.com/yantar92>