---- On Mon, 05 Feb 2024 15:00:18 +0100  Ihor Radchenko  wrote --- 
 
 > Yes. The right fix would be extracting the filter from
 > `org-babel-comint-with-output' and re-using it.

This message documents my progress so that I may switch focus to Bruno's patches in "Asynchronous blocks for everything" attention (https://list.orgmode.org/65cfa0d8.050a0220.cb569.ce34@mx.google.com/T/#u).

Attached is a failed attempt at extracting the filter in =org-babel-comint-with-output=.  It tries to extract the filter more-or-less directly:

1. take the filter code from =org-babel-comint-with-output= and put it
into a separate function, =org-babel-comint-process-output-filter=

2. call =org-babel-comint-process-output-filter= from
=org-babel-comint-with-output= and =org-babel-comint-async-filter=

The unmodified =org-babel-comint-with-output= has a comment that says, "Filter out prompts".  This is misleading.  The filter code does two things: removes prompts *and* removes echoed input.

The problem is the filter which removes echoes uses the body of the source block.  It's unclear how to give =org-babel-comint-async-filter= the block body.  =org-babel-comint-async-filter= is a =comint-output-filter-function= which receives a single input, "a string containing the text as originally inserted" in the comint buffer.

Thoughts:

- Split prompt filtering and input echoing into two filters
  + this seems to imply a =-hook= or =-functions= type implementation
  + where could input echo filter go?  Where has access to the block body?
-  creating a generic prompt filter duplicates =ob-shell-async-chunk-callback= or, more fundamentally, =org-babel-comint-async-chunk-callback=
- What would it take to consolidate output filtering?  In addition to prompt filtering and input echo filtering, ob-shell filters the =org-babel-sh-eoe-indicator=.  I'm sure there's other filtering that happens on block output.  Wouldn't it be nice if that were in a single place, like right before results are inserted?

Please feel free to provide feedback and suggestions.

--
Matt Trzcinski
Emacs Org contributor (ob-shell)
Learn more about Org mode at https://orgmode.org
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