Re: [Bug-apl] Another attention signal issue

[Blake McBride]

Does this help?

This may be related to the cooked/uncooked/rare terminal modes; ^C does not always send a signal. It seems likely that readline uncooks the terminal, and thus any signals caused by keyboard input must be due to logic within readline itself; it seems plausible that it might only trigger a SIGINT on two sequential ^Cs (especially since for many programs that utilise readline such as shells and REPLs, the program exiting on a single ^C would be very annoying!).

You might be able to change this behaviour by using the readline API to rebind ^C to some of your own code that triggers a SIGINT. I haven't used readline from Haskell, just from C, so I'm not sure exactly how you'd go about this, but the binding seems rich enough to achieve it.

Blake McBride

www.arahant.com

Cell:    615-394-6760

Office:  615-376-5500

Fax:     615-377-6006

On Mon, Jul 21, 2014 at 12:39 PM, Juergen Sauermann <address@hidden> wrote:

Hi David,

I see. The problem is that the line input (readline) does not return even
though I tell it to (by setting rl_done in the signal handler for ^C). I haven't
found a way to fix this (hints more than welcome). This could also be caused
by terminal settings ("cooked mode") but I thought readline would handle this.

Long term I will most likely replace readline because so far it has created more problems
than it has helped. That would be a bigger issue and should also be aligned with Elias'
emacs mode. So it would  be after the next GNU APL release.

/// Jürgen

On 07/21/2014 06:32 PM, David B. Lamkins wrote:

Thanks, Jüergen.

The real issue, from my perspective, is that APL doesn't report the
ATTENTION message until it sees a newline on input. It seems to me that
typing a ^C should immediately suspend execution and show the ATTENTION
message.

On Mon, 2014-07-21 at 18:23 +0200, Juergen Sauermann wrote:

Hi David,

I have changed readline to display a new line right after ^C, see SVN 382.

For reasons that I don't fully understand, the next character after ^C 
will be eaten by
readline; I tried a number of things to prevent this but haven't succeeded.

I believe readline will be one of the next things removed from GNU APL.

/// Jürgen


On 07/21/2014 02:32 AM, David Lamkins wrote:

When the session is not executing APL code, the attention signal is 
not handled until the next newline.

To see this, enter the characters Control-C, 1, Return.


-- 
"The secret to creativity is knowing how to hide your sources."
   Albert Einstein


http://soundcloud.com/davidlamkins
http://reverbnation.com/lamkins
http://reverbnation.com/lcw
http://lamkins-guitar.com/
http://lamkins.net/
http://successful-lisp.com/