Hello Geiser Users!
I've hit a strange error, when using paginated output via a pager and
`open-output-pipe` with GNU Guile 3.0.8, installed via GNU Guix and Emacs `GNU
Emacs 28.2 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.30, cairo version
1.16.0)` also installed via GNU Guix. Here is the GNU Guile code, which I use
for paginated output:
~~~~
(library (paginated-output)
(export output-paginated)
(import (except (rnrs base) let-values)
(only (guile)
;; lambdas
lambda* λ
;; control structures
when
;; display
display
simple-format
;; strings
string-join
string-append
string-tokenize
;; characters
char-set
char-set-complement
;; environment variables
getenv
;; path stuff
search-path)
;; pipes
(ice-9 popen))
;; `path-as-string->list`'s logic is copied from GNU
;; Guix. Some comments added. See:
;;https://git.savannah.gnu.org/cgit/guix.git/tree/guix/build/utils.scm?id=c0bc08d82c73e464a419f213d5ae5545bc67e2bf#n573.
(define path-as-string->list
(lambda* (path #:optional (separator #\:))
(if separator
(string-tokenize path
;; Match everything except the
;; separator.
(char-set-complement
(char-set separator)))
;; Otherwise simply return a list containing the
;; path to be sure to always return a list.
(list path))))
;; `find-executable-on-path` is adapted from GNU Guix's
;; `which` procedure. See:
;;https://git.savannah.gnu.org/cgit/guix.git/tree/guix/build/utils.scm?id=c0bc08d82c73e464a419f213d5ae5545bc67e2bf#n617
(define (find-executable-on-path executable)
"Return the complete file name for EXECUTABLE as found in
${PATH}, or #f if EXECUTABLE could not be found."
;; search-path is a procedure defined in GNU Guile
(search-path
;; Check the PATH for the executable.
(path-as-string->list (getenv "PATH"))
executable))
(define find-pager
(λ ()
(or (getenv "PAGER")
(find-executable-on-path "more")
(find-executable-on-path "less"))))
;;; Now onto the actual matter of using open-pipe ...
(define open-output-pipe*
(λ (command . args)
(open-output-pipe
(string-join (cons command args) " "))))
(define output-paginated
(λ (message lines-per-page)
(let* ([pager-args
;; Here we assume, that the pager will support
;; an argument "-<number>". This might not always be
;; true.
(list (string-append "-" (number->string lines-per-page)))]
[pager-pipe
;; Execute the pager command in a subprocess
;; with its arguments and return an output
;; pipe to the pager.
(apply open-output-pipe* (find-pager) pager-args)])
(display (simple-format #f "~a\n" message)
pager-pipe)
;; Ultimately close pipe after being done with
;; writing to it.
(close-pipe pager-pipe)))))
~~~~
When I use this code, I get an error as follows:
~~~~
scheme@(guile-user)> (load "lib/paginated-output.scm")
...
scheme@(guile-user)> (import (paginated-output))
scheme@(guile-user)> (output-paginated "a\nb\nc\nd\ne\nf\ng\n" 3)
a
b
c
--More--
d
...skipping 1 line
f
g
$8 = done
;;; <unknown-location>: warning: possibly unbound variable `er-no-values'
ice-9/boot-9.scm:1685:16: In procedure raise-exception:
Unbound variable: er-no-values
Entering a new prompt. Type `,bt' for a backtrace or `,q' to continue.
scheme@(guile-user) [1]> ,bt
In current input:
112:0 1 (_)
In ice-9/boot-9.scm:
1685:16 0 (raise-exception _ #:continuable? _)
~~~~
There is no `er-no-values` in my code, so it seems this is something Geiser
internal? The backtrace is not really helpful to me either.
I tried adding a `'done` as a return value of `output-paginated`, but that did
not change anything.
However, when I instead run an `ansi-term` or `shell` and inside those `guile`
and then do the same calls there, I do not get this error.
Could this be an issue of Geiser with pipes?
Best regards,
Zelphir
--
repositories:https://notabug.org/ZelphirKaltstahl
