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From: miha@kamnitnik.top
To: Ihor Radchenko <yantar92@posteo.net>, emacs-devel@gnu.org
Subject: Re: comint-output-filter-functions and multi-line input
Date: Mon, 17 Oct 2022 23:23:58 +0200	[thread overview]
Message-ID: <87v8oidtzl.fsf@miha-pc> (raw)
In-Reply-To: <87y1tgqhmc.fsf@localhost>

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Ihor Radchenko <yantar92@posteo.net> writes:

> Hello,
>
> I am trying to figure out how to programmatically capture output of a
> multi-line bash script in comint buffer.
>
> Consider:
>
> [yantar92:/tmp] $ 
>> if true
>> then
>> echo "hello"
>> fi
> hello
>
> Each line is submitted to shell via comint-send-input and, AFAIK, the
> result can be collected using `comint-output-filter-functions'.
>
> I expect the `comint-output-filter-functions' to be called on "hello"
> line. However, it does not seem to be the case. Empty "" corresponding
> to "> " PS2 prompts upon sending incomplete script lines are also
> passed.
>
> Is it possible to distinguish the actual script output, empty lines in
> the actual script output, and the incomplete prompts?

You could prepend your multiline command with a dummy
'echo multiline_starts_here' command have your
'comint-output-filter-functions' discard output that arrives before
"multiline_starts_here".

Or maybe inject something like 'oldps=$PS2; PS2=""' before the command
and 'PS2=$oldps' after the command. But whether this works could depend
on the shell, some shells might have something like $PS3 or $RPS1, for
example.

You could also accept-process-output after sending each individual line
separately, but this depends on the user not customizing PS2="" in his
bashrc.

As far as Emacs is concerned, PS1/PS2 prompts and non-prompt process
output is all data, read from a single file descriptor. I don't think
it's possible to distinguish them reliably without the above tricks or
some other heuristics.

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  reply	other threads:[~2022-10-17 21:23 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-16  8:48 comint-output-filter-functions and multi-line input Ihor Radchenko
2022-10-17 21:23 ` miha [this message]
2022-10-18  5:28   ` Ihor Radchenko
2022-10-18  7:22     ` miha
2022-10-18  7:35       ` Ihor Radchenko
2022-10-18 11:15         ` miha
2022-10-21  5:32           ` Ihor Radchenko
2022-10-18 13:38         ` Stefan Monnier
2022-10-17 21:27 ` Stefan Monnier
2022-10-18  6:00   ` Ihor Radchenko
2022-10-18 23:22     ` Rudolf Adamkovič
2022-10-21  5:35       ` Ihor Radchenko

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