Scheme Interpreter in Emacs and Readline

Scheme Interpreter in Emacs and Readline

[Jakub Jankiewicz]

I have problem in creating Scheme Interpreter in Node.js that can be run
using Emacs run-scheme command. I use Readline library in Node.js and when I
resize the window or frame it keep adding prompt to the prompt line. I've
asked on StackOverflow and also on emacs mailing list but no one answered.

[How to write Node.js REPL that works with GNU Emacs?][1]

Is there special thing the interpreter need to be doing, so it work with
Comint mode? I have the same if I run with emacs -q. Does Emacs run-scheme
work with Readline? Does anyone have issues with this? Is this a bug? I would
like to know if there is workaround. Kawa and Guile works fine in GNU Emacs,
I was checking Kawa source code and it don't use Readline it use stdin stream
and println in Java.

I have this code in my .emacs file:


(defun lips ()
  "call run-scheme with guile interpreter."
  (interactive)
  (run-scheme "/home/kuba/projects/jcubic/lips/bin/lips.js"))


and I have also this 

(autoload 'scheme-mode "cmuscheme" "Major mode for Scheme." t)
(autoload 'run-scheme "cmuscheme" "Switch to interactive Scheme buffer." t)
;; this shouldn't change anything since I'm running the function with argument
(setq scheme-program-name "/home/kuba/projects/jcubic/lips/bin/lips.js")
(add-hook 'scheme-mode-hook 'turn-on-font-lock)

;; there was issue with double echo
;; see my Question on Emacs StackExachange
;; [How to run custom scheme written in node.js using readline in
;; emacs?][2]
(setq comint-process-echoes t)
(setq comint-input-ignoredups t)
(setq comint-prompt-read-only t)

(add-hook 'comint-mode-hook
          (lambda()
            (setq truncate-lines 1)))

[1]: https://stackoverflow.com/q/60987722/387194
[2]: https://emacs.stackexchange.com/q/57521/10438

--
Jakub Jankiewicz, Web Developer
https://jcubic.pl/me

Re: Scheme Interpreter in Emacs and Readline

[Jakub Jankiewicz]

> What do you mean by "when I resize the window or frame it keep adding
> prompt to the prompt line"?

I have prompt "lips> " and when I resize Emacs window on Fedora GNU/Linux
(the only system I was testing this). on each resize I get new prompt so when
I keep resizing I have something like this:

lips> lips> lips> lips> lips>

and they are all prompt because I can't delete it. Unless something wierd is
happening.

> It would also probbaly be helpful if you could post the source of your
> Scheme interpreter.

Sorry about that, my Scheme Interpreter is here:

https://github.com/jcubic/lips/tree/devel

Please use devel branch since it's most up to date, I still try to make it
compatible with R5RS, before I release new version, it will 1.0.

The executable is in bin directry (there are not much code, but it would be
easier to have link that you can run insead of send this to the mailing list.

https://github.com/jcubic/lips/blob/devel/bin/lips.js

Just run:

	git clone https://github.com/jcubic/lips.git
	cd lips
	git checkout devel

and run in GUI Emacs:

	(run-scheme "<PATH>/lips/bin/lips.js")

and resize the Frame or buffer's window if you have multiple windows.


And I need to add that I was looking at Node.js source code, there is lot of
code but it also use Readline and Node.js works in run-js (I'm not sure if it
use something else for --interactive option that was suggested when I've
search how to run node in Emacs).

I've tested my interpeter with same run-js and I have same issue with
duplicated prompt.

--
Jakub Jankiewicz, Web Developer
https://jcubic.pl/me

Re: Scheme Interpreter in Emacs and Readline

[Po Lu]

Jakub Jankiewicz <jcubic@onet.pl> writes:

>> What do you mean by "when I resize the window or frame it keep adding
>> prompt to the prompt line"?
>
> I have prompt "lips> " and when I resize Emacs window on Fedora GNU/Linux
> (the only system I was testing this). on each resize I get new prompt so when
> I keep resizing I have something like this:
>
> lips> lips> lips> lips> lips>
>
> and they are all prompt because I can't delete it. Unless something wierd is
> happening.
>
>> It would also probbaly be helpful if you could post the source of your
>> Scheme interpreter.
>
> Sorry about that, my Scheme Interpreter is here:
>
> https://github.com/jcubic/lips/tree/devel
>
> Please use devel branch since it's most up to date, I still try to make it
> compatible with R5RS, before I release new version, it will 1.0.
>
> The executable is in bin directry (there are not much code, but it would be
> easier to have link that you can run insead of send this to the mailing list.
>
> https://github.com/jcubic/lips/blob/devel/bin/lips.js
>
> Just run:
>
> 	git clone https://github.com/jcubic/lips.git
> 	cd lips
> 	git checkout devel
>
> and run in GUI Emacs:
>
> 	(run-scheme "<PATH>/lips/bin/lips.js")
>
> and resize the Frame or buffer's window if you have multiple windows.
>
>
> And I need to add that I was looking at Node.js source code, there is lot of
> code but it also use Readline and Node.js works in run-js (I'm not sure if it
> use something else for --interactive option that was suggested when I've
> search how to run node in Emacs).
>
> I've tested my interpeter with same run-js and I have same issue with
> duplicated prompt.
>
> --
> Jakub Jankiewicz, Web Developer
> https://jcubic.pl/me

I'm not sure about run-js, but I turned off Readline in your
interpreter, and it now works flawlessly inside comint.  Since Readline
is pretty much useless anyways there, it might be worth it to turn it
off inside Emacs. (ie check the EMACS and INSIDE_EMACS variables, or add
something like CMU's `-emacs' flag.)

Bash does the same thing too;
https://lists.gnu.org/archive/html/bug-bash/2015-03/msg00179.html

Re: Scheme Interpreter in Emacs and Readline

[Jakub Jankiewicz]

On Sun, 19 Apr 2020 08:02:02 +0800
Po Lu <luangruo@yahoo.com> wrote:

> Jakub Jankiewicz <jcubic@onet.pl> writes:
> 
> >> What do you mean by "when I resize the window or frame it keep adding
> >> prompt to the prompt line"?  
> >
> > I have prompt "lips> " and when I resize Emacs window on Fedora GNU/Linux
> > (the only system I was testing this). on each resize I get new prompt so
> > when I keep resizing I have something like this:
> >  
> > lips> lips> lips> lips> lips>  
> >
> > and they are all prompt because I can't delete it. Unless something wierd
> > is happening.
> >  
> >> It would also probbaly be helpful if you could post the source of your
> >> Scheme interpreter.  
> >
> > Sorry about that, my Scheme Interpreter is here:
> >
> > https://github.com/jcubic/lips/tree/devel
> >
> > Please use devel branch since it's most up to date, I still try to make it
> > compatible with R5RS, before I release new version, it will 1.0.
> >
> > The executable is in bin directry (there are not much code, but it would
> > be easier to have link that you can run insead of send this to the
> > mailing list.
> >
> > https://github.com/jcubic/lips/blob/devel/bin/lips.js
> >
> > Just run:
> >
> > 	git clone https://github.com/jcubic/lips.git
> > 	cd lips
> > 	git checkout devel
> >
> > and run in GUI Emacs:
> >
> > 	(run-scheme "<PATH>/lips/bin/lips.js")
> >
> > and resize the Frame or buffer's window if you have multiple windows.
> >
> >
> > And I need to add that I was looking at Node.js source code, there is lot
> > of code but it also use Readline and Node.js works in run-js (I'm not
> > sure if it use something else for --interactive option that was suggested
> > when I've search how to run node in Emacs).
> >
> > I've tested my interpeter with same run-js and I have same issue with
> > duplicated prompt.
> >
> > --
> > Jakub Jankiewicz, Web Developer
> > https://jcubic.pl/me  
> 
> I'm not sure about run-js, but I turned off Readline in your
> interpreter, and it now works flawlessly inside comint.  Since Readline
> is pretty much useless anyways there, it might be worth it to turn it
> off inside Emacs. (ie check the EMACS and INSIDE_EMACS variables, or add
> something like CMU's `-emacs' flag.)
> 
> Bash does the same thing too;
> https://lists.gnu.org/archive/html/bug-bash/2015-03/msg00179.html
> 

I've used this:

const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout,
    prompt: prompt,
    terminal: !!process.stdin.isTTY && !(process.env.EMACS ||
                                         process.env.INSIDE_EMACS)
});

Thanks, it works perfetly, this will be required for any Readline Node.js
interpreter or REPL that runs in GNU Emacs.

--
Jakub Jankiewicz, Web Developer
https://jcubic.pl/me