help with add-to-list syntax

help with add-to-list syntax

[BP25]

Hello! Could any of you be so kind as to help me understand this,
please? I have

(custom-set-variables
'(warning-suppress-types '((undo\ discard-info))))

in my .emacs. If I start emacs, do load-file .emacs, then evaluate
(add-to-list 'warning-suppress-types '(undo\ discard-info)) I get an
error saying the variable warning-suppress-types is void. However if I
start emacs, do load-file .emacs, then do C-h v warning-suppress-types
then I see the value being ((undo\ discard-info)) and if I evaluate
(add-to-list 'warning-suppress-types '(undo\ discard-info)) then
everything goes through without error. Why?!

Please, let me know! (and please, CC: my email address in your reply
because I'm not subscribed to this list)

Re: help with add-to-list syntax

[Michael Heerdegen via Users list for the GNU Emacs text editor]

BP25 <bp25@riseup.net> writes:

> Hello! Could any of you be so kind as to help me understand this,
> please? I have
>
> (custom-set-variables
> '(warning-suppress-types '((undo\ discard-info))))
>
> in my .emacs.

Why is the space character escaped?

> If I start emacs, do load-file .emacs, then evaluate
> (add-to-list 'warning-suppress-types '(undo\ discard-info)) I get an
> error saying the variable warning-suppress-types is void.

You are sure there was no typo involved?

Apart from that I dunno, that makes no sense unless your .emacs messes
up emacs in a crazy way.


Michael.

Re: help with add-to-list syntax

[Joel Reicher]

BP25 <bp25@riseup.net> writes:

> Hello! Could any of you be so kind as to help me understand 
> this, please? I have
>
> (custom-set-variables
> '(warning-suppress-types '((undo\ discard-info))))
>
> in my .emacs. If I start emacs, do load-file .emacs, then 
> evaluate (add-to-list 'warning-suppress-types '(undo\ 
> discard-info)) I get an error saying the variable 
> warning-suppress-types is void.

Instead of doing add-to-list, can you do C-h v and confirm the 
variable setting that you expected didn't work?

That would give a simpler thing to investigate.

Cheers,

        - Joel

Re: help with add-to-list syntax

[BP25]

Hello!

First, the space character should not be escaped, this was my
mistake. But it changes nothing with respect to my problem.

On Wed, Oct 30 2024, Joel Reicher wrote:
>> Hello! Could any of you be so kind as to help me understand this,
>> please? I have
>>
>> (custom-set-variables '(warning-suppress-types '((undo\
>> discard-info))))
>>
>> in my .emacs. If I start emacs, do load-file .emacs, then evaluate
>> (add-to-list 'warning-suppress-types '(undo\ discard-info)) I get an
>> error saying the variable warning-suppress-types is void.
>
> Instead of doing add-to-list, can you do C-h v and confirm the
> variable setting that you expected didn't work?
Do you mean this? -> If I start emacs, do load-file .emacs, then do C-h v
warning-suppress-types then I see the value being ((undo\ discard-info))

Re: help with add-to-list syntax

[Michael Heerdegen]

BP25 <bp25@riseup.net> writes:

> Hello! Could any of you be so kind as to help me understand this,
> please? I have
>
> (custom-set-variables
> '(warning-suppress-types '((undo\ discard-info))))
>
> in my .emacs. If I start emacs, do load-file .emacs, then evaluate
> (add-to-list 'warning-suppress-types '(undo\ discard-info)) I get an
> error saying the variable warning-suppress-types is void.

After thinking about this again:
The explanation for your little miracle is probably that the variable is
autoloaded and the defining library "warnings" not necessarily loaded at
startup.  `custom-set-variables' is clever enough to do the right thing
anyway.  C-h v loads the defining library as a side effect so you always
see a defined variable even when it had not yet been defined.

The details may differ a bit depending on your Emacs version.

Michael.

Re: help with add-to-list syntax

[Joel Reicher]

BP25 <bp25@riseup.net> writes:

> On Wed, Oct 30 2024, Joel Reicher wrote:
>>> Hello! Could any of you be so kind as to help me understand 
>>> this, please? I have
>>>
>>> (custom-set-variables '(warning-suppress-types '((undo\ 
>>> discard-info))))
>>>
>>> in my .emacs. If I start emacs, do load-file .emacs, then 
>>> evaluate (add-to-list 'warning-suppress-types '(undo\ 
>>> discard-info)) I get an error saying the variable 
>>> warning-suppress-types is void.
>>
>> Instead of doing add-to-list, can you do C-h v and confirm the 
>> variable setting that you expected didn't work?
> Do you mean this? -> If I start emacs, do load-file .emacs, then 
> do C-h v warning-suppress-types then I see the value being 
> ((undo\ discard-info))

Why are you doing a load-file .emacs? That should happen 
automatically, unless there is something very strange about your 
setup, and if there is something very strange about your setup, 
maybe that's the reason other things are failing?

Regards,

        - Joel