GNU bug report logs - #75860
Somewhat confusing exception message with append

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Tomas Nordin <tomasn <at> posteo.net>
To: bug-guile <at> gnu.org
Subject: Somewhat confusing exception message with append
Date: Sun, 26 Jan 2025 13:04:04 +0000

Hello Guile!

As expected, the following raises an exception:

    (append 'a '(b) '()) =>
    ice-9/boot-9.scm:1676:22: In procedure raise-exception:
    In procedure append: Wrong type argument in position 1 (expecting empty list): a

And so does this:

    (append '(a) 'b '()) =>
    ice-9/boot-9.scm:1676:22: In procedure raise-exception:
    In procedure append: Wrong type argument in position 1 (expecting empty list): b

Note that the a-thing is the first and the b-thing the second argument
in both calls. 'a is at fault in the first and 'b is at fault in the
second call.

But, in both cases the faulty argument is reported to be in position 1.
I would expect maybe position 2 to be complained about from the second
call.

Also, I wonder why we are "(expecting empty list)" in place of the
non-list things?

I made the above observations, if it's a bug or not, I don't know.

(version) => "3.0.9.140-d8df3-dirty"

Have a great Sunday
--
Tomas

Message #8 received at 75860 <at> debbugs.gnu.org (full text, mbox):

From: Rob Browning <rlb <at> defaultvalue.org>
To: Tomas Nordin <tomasn <at> posteo.net>, 75860 <at> debbugs.gnu.org
Subject: Re: bug#75860: Somewhat confusing exception message with append
Date: Tue, 18 Mar 2025 13:28:42 -0500

Tomas Nordin <tomasn <at> posteo.net> writes:

> But, in both cases the faulty argument is reported to be in position 1.
> I would expect maybe position 2 to be complained about from the second
> call.

...and it appears to be correct when run via -c or a script.

-- 
Rob Browning
rlb @defaultvalue.org and @debian.org
GPG as of 2011-07-10 E6A9 DA3C C9FD 1FF8 C676 D2C4 C0F0 39E9 ED1B 597A
GPG as of 2002-11-03 14DD 432F AE39 534D B592 F9A0 25C8 D377 8C7E 73A4

Message #11 received at 75860 <at> debbugs.gnu.org (full text, mbox):

From: Tomas Nordin <tomasn <at> posteo.net>
To: Rob Browning <rlb <at> defaultvalue.org>, 75860 <at> debbugs.gnu.org
Subject: Re: bug#75860: Somewhat confusing exception message with append
Date: Wed, 19 Mar 2025 23:09:56 +0000

Hello Rob

Rob Browning <rlb <at> defaultvalue.org> writes:

> Tomas Nordin <tomasn <at> posteo.net> writes:
>
>> But, in both cases the faulty argument is reported to be in position 1.
>> I would expect maybe position 2 to be complained about from the second
>> call.
>
> ...and it appears to be correct when run via -c or a script.

Do you mean like

    $ guile -c "(append '(a) 'b '())"
    [...]
    In procedure append: Wrong type argument in position 2 (expecting empty list): b

Here the position is reported as 2 (as expected I think). Was that what
you also observed? (Still confusing for me that we are expecting an
empty list).

Message #14 received at 75860 <at> debbugs.gnu.org (full text, mbox):

From: Rob Browning <rlb <at> defaultvalue.org>
To: Tomas Nordin <tomasn <at> posteo.net>, 75860 <at> debbugs.gnu.org
Subject: Re: bug#75860: Somewhat confusing exception message with append
Date: Wed, 19 Mar 2025 21:41:37 -0500

Tomas Nordin <tomasn <at> posteo.net> writes:

> Do you mean like
>
>     $ guile -c "(append '(a) 'b '())"
>     [...]
>     In procedure append: Wrong type argument in position 2 (expecting empty list): b
>
> Here the position is reported as 2 (as expected I think). Was that what
> you also observed? (Still confusing for me that we are expecting an
> empty list).

Right, I see 1 in the repl and 2 via -c or a file.

-- 
Rob Browning
rlb @defaultvalue.org and @debian.org
GPG as of 2011-07-10 E6A9 DA3C C9FD 1FF8 C676 D2C4 C0F0 39E9 ED1B 597A
GPG as of 2002-11-03 14DD 432F AE39 534D B592 F9A0 25C8 D377 8C7E 73A4

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