Re: Display greeting in REPL buffer before process starts

[Jose A. Ortega Ruiz]

Hi,

On Sat, Mar 20 2021, Dmitry Matveyev wrote:

> Hi, I'm trying to revive and improve Gerbil integration with Geiser.

That's great news, thanks!

> Gerbil's interpreter is run with `gxi -` with `-` being simultaneously
> "run in interactive mode" and "do not load init file". So I load file
> manually here:
> https://gitlab.com/greenfork/geiser-gerbil/-/blob/master/elisp/geiser-gerbil.el#L314
>
> But init file also shows a greeting message with `(displayln
> gerbil-greeting)` which is not displayed in Geiser. Could I get any
> suggestions on how to show this greeting message in REPL before prompt
> `>`?

When you use geiser-load-file (check its definition in
geiser-compile.el), any output from that command is parsed as an
evaluation response, and not displayed in the repl.  If you want to
capture messages you could use the low-level geiser-eval--send/wait,
and process its result.  Maybe Guile's startup function(s) will give you
an idea of how:

https://gitlab.com/emacs-geiser/guile/-/blob/master/geiser-guile.el#L379

there, guile is setting a variable, not loading anything, but the idea
would be the same: you specify a form to evaluate that loads the file
(the 'code'), use geiser-eval--send/wait, and parse its result (the
message will be under a key named "output")... that, however, won't
print that message in the REPL buffer by itself, you'd need to.

But i am thinking that a much easier way to do this might be simply to
invoke gxi with flags to the effect of loading the file you're
interested in.  You can specify a 'binary' function that computes
them. The advantage is that, when calling the binary (with any flags),
stdout is still redirected to the REPL.  See

https://gitlab.com/emacs-geiser/guile/-/blob/master/geiser-guile.el#L139
https://gitlab.com/emacs-geiser/guile/-/blob/master/geiser-guile.el#L430

(the value returned by the 'binary' method can be a list, instead of a
single string).

HTH,
jao
-- 
Art is the elimination of the unnecessary.
 -Pablo Picasso, painter, and sculptor (1881-1973)