Re: Prompting for input inside IDE run (was Reading from STDIN)

How do you run those programs inside emacs? I guess this is on Windows? Are you using Powershell as your shell-file-name?

One annoying effect I see on Windows is that STDOUT is buffered. So, if you're expecting a prompt, then you won't see it in time, but you can still enter your input line when the program seems to "hang". The w32 FAQ has a workaround for "Perl script buffering".

I could run the following program under M-x perldb and M-x eshell, and it behaves as I would expect:

use 5.028;

# Turn all buffering off.
select((select(STDOUT), $| = 1)[0]);
select((select(STDERR), $| = 1)[0]);
select((select(STDIN), $| = 1)[0]);

print "Give me a cookie: ";
my $thing = readline(STDIN);
$thing =~ /^(a )?cookie$/ or die "That was no cookie.\n";
say "Thanks and goodbye!";
[download]

Comment on Re: Prompting for input inside IDE run (was Reading from STDIN) Download Code

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Re^2: Prompting for input inside IDE run (was Reading from STDIN) by LanX (Saint) on Mar 27, 2023 at 12:45 UTC
> How do you run those programs inside emacs? I guess this is on Windows? With mode-compile, which is not core, but nevertheless the default in cperl-mode. You may want to look into the `perl` menu in the top-bar after activating cperl-mode. <menu-bar> <Perl> <Run> runs the command mode-compile, which is an interactive autoloaded compiled Lisp function in `mode-compile.el'. [download] Auto flush was helpful yes, but input is still ignored. Actually all input is considered compilation or error navigation commands, which makes sense in a buffer with start Now I'm thinking about making my script automatically redirecting stdout and stdin to a spawned console /or buffer. This while still keeping stder in the compilation buffer... I did this before in order to debug Term::ReadLine apps, have to dig that out again. I'm weak on tty Channel foo ... Cheers Rolf _{(addicted to the 𐍀𐌴𐍂𐌻 Programming Language :) Wikisyntax for the Monastery}	[reply] [d/l] [select]
Re^3: Prompting for input inside IDE run (was Reading from STDIN) by haj (Vicar) on Mar 27, 2023 at 14:52 UTC
With mode-compile, which is no not core but the default in cperl-mode. That would have been helpful to know. That entry is disabled in my Emacs because I don't have mode-compile. Heck, that thing is pretty stale and can't be byte-compiled nor `M-x eval-buffer`ed in Emacs 27... Anyway, `mode-compile` is the culprit. Contrary to its name, it runs the program, using a mechanism which does not make STDIN of the Perl process available to you. What you could do is wrap the following lisp snippet into a command which suits you: `(compile "perl your_script.pl" t)` Replacing the program name `perl` and script name `your_script.pl` by variables is left as an exercise to the reader. The `t` parameter does the trick to give you what Emacs calls a "comint" environment. So, you end up in a buffer `compilation` in compilation-mode with "clickable" error messages, but the buffer is not read-only, you can just enter text after the prompt.	[reply] [d/l]
Re^4: Prompting for input inside IDE run (was Reading from STDIN) by LanX (Saint) on Mar 27, 2023 at 14:57 UTC
> (compile "perl your_script.pl" t) Yes, thanks, I already figured this out in the meantime. > variables is left as an exercise to the reader. That's one of the things mode-compile does for me (and is expected from an IDE nowadays) I will try to find a way to patch/configure mode-compile accordingly. Cheers Rolf _{(addicted to the 𐍀𐌴𐍂𐌻 Programming Language :) Wikisyntax for the Monastery}	[reply]


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