bug in message-message mode?

bug in message-message mode?

[Emanuel Berg via Users list for the GNU Emacs text editor]

In `message-mode', when I have point at C (LINE FEED (LF)) and
a equals HYPHEN-MINUS and B SPACE, i.e.

AABC
   ^ here :)

and do `message-beginning-of-line', nothing happens!

OTOH hand maybe it isn't message-mode's fault because
`beginning-of-line' also doesn't work ...

-- 
underground experts united
https://dataswamp.org/~incal

Re: bug in message-message mode?

[Tassilo Horn]

Emanuel Berg via Users list for the GNU Emacs text editor <help-gnu-emacs@gnu.org> writes:

> In `message-mode', when I have point at C (LINE FEED (LF)) and
> a equals HYPHEN-MINUS and B SPACE, i.e.
>
> AABC
>    ^ here :)
>
> and do `message-beginning-of-line', nothing happens!

I guess there is some special treatment for the signature separator
"-- \n".  The two hyphens and the space have a `field' property value
`signature' which might explain the behavior, see (info "(elisp)
Fields").

Bye,
Tassilo

Re: bug in message-message mode?

[Emanuel Berg via Users list for the GNU Emacs text editor]

Tassilo Horn wrote:

>> In `message-mode', when I have point at C (LINE FEED (LF))
>> and a equals HYPHEN-MINUS and B SPACE, i.e.
>>
>> AABC
>>    ^ here :)
>>
>> and do `message-beginning-of-line', nothing happens!
>
> I guess there is some special treatment for the signature
> separator "-- \n". The two hyphens and the space have
> a `field' property value `signature' which might explain the
> behavior, see (info "(elisp) Fields").

OK, but why?

The --- after the header is also a delimiter, but there
it works. (See `rfc822-goto-eoh'.)

There's no reason it should work on the signature delimiter.

Or is there?

-- 
underground experts united
https://dataswamp.org/~incal

Re: bug in message-message mode?

[Tassilo Horn]

Emanuel Berg via Users list for the GNU Emacs text editor <help-gnu-emacs@gnu.org> writes:

>>> In `message-mode', when I have point at C (LINE FEED (LF))
>>> and a equals HYPHEN-MINUS and B SPACE, i.e.
>>>
>>> AABC
>>>    ^ here :)
>>>
>>> and do `message-beginning-of-line', nothing happens!
>>
>> I guess there is some special treatment for the signature separator
>> "-- \n". The two hyphens and the space have a `field' property value
>> `signature' which might explain the behavior, see (info "(elisp)
>> Fields").
>
> OK, but why?
>
> The --- after the header is also a delimiter, but there it works. (See
> `rfc822-goto-eoh'.)
>
> There's no reason it should work on the signature delimiter.
>
> Or is there?

I don't know.  But it seems that this behavior is only there when the
text has both a `field' and `rear-nonsticky' property.  You can
experiment with it in *stratch*:

--8<---------------cut here---------------start------------->8---
(insert "\n\n"
        (propertize "test" 'field 'foobar 'rear-nonsticky t)
        "\n")
--8<---------------cut here---------------end--------------->8---

Bye,
Tassilo

Re: bug in message-message mode?

[Emanuel Berg via Users list for the GNU Emacs text editor]

Tassilo Horn wrote:

>> The --- after the header is also a delimiter, but there it
>> works. (See `rfc822-goto-eoh'.)
>>
>> There's no reason it should work on the
>> signature delimiter.
>>
>> Or is there?
>
> I don't know. But it seems that this behavior is only there
> when the text has both a `field' and `rear-nonsticky'
> property. You can experiment with it in *stratch*:
>
> (insert "\n\n"
>         (propertize "test" 'field 'foobar 'rear-nonsticky t)
>         "\n")

OK, I don't know what `rear-nonsticky' is supposed to denote
but '-- \n' isn't a field, with the fields it makes sense to
first go to the beginning of the field, then (as already)
there go to the beginning of the line ...

But on the signature delimiter - and only at the last char -
nothing happens at all.

A bug maybe?

-- 
underground experts united
https://dataswamp.org/~incal

Re: bug in message-message mode?

[Tassilo Horn]

Emanuel Berg via Users list for the GNU Emacs text editor <help-gnu-emacs@gnu.org> writes:

>>> The --- after the header is also a delimiter, but there it
>>> works. (See `rfc822-goto-eoh'.)
>>>
>>> There's no reason it should work on the
>>> signature delimiter.
>>>
>>> Or is there?
>>
>> I don't know. But it seems that this behavior is only there when the
>> text has both a `field' and `rear-nonsticky' property. You can
>> experiment with it in *stratch*:
>>
>> (insert "\n\n"
>>         (propertize "test" 'field 'foobar 'rear-nonsticky t)
>>         "\n")
>
> OK, I don't know what `rear-nonsticky' is supposed to denote but '--
> \n' isn't a field,

Well, somebody thought it would be a good idea to place a field property
on "-- " and I guess there were reasons.  Maybe one effect is that it
supresses whitespace cleanup (the trailing space is significant), and
paragraph filling.

> with the fields it makes sense to first go to the beginning of the
> field, then (as already) there go to the beginning of the line ...

Yes, that's controlled by `message-beginning-of-line'.

> But on the signature delimiter - and only at the last char -
> nothing happens at all.
>
> A bug maybe?

Maybe.  Or an nonintended side-effect.  If it bothers you, file a bug
report.

Bye,
Tassilo

Re: bug in message-message mode?

[Emanuel Berg via Users list for the GNU Emacs text editor]

Tassilo Horn wrote:

> Maybe one effect is that it supresses whitespace cleanup
> (the trailing space is significant), and paragraph filling.

But then one should add that to whatever function is
responsible for that ...

Or add something else that is unique for "-- \n" and isn't
acted upon by beginning-of-line functions ...

-- 
underground experts united
https://dataswamp.org/~incal

Re: bug in message-message mode?

[Emanuel Berg via Users list for the GNU Emacs text editor]

Tassilo Horn wrote:

> Maybe. Or an nonintended side-effect. If it bothers you,
> file a bug report.

(defun message-bol ()
  (interactive)
  (let ((beg (point))
        (end (progn (message-beginning-of-line) (point))) )
    (when (= beg end)
      (forward-line 0) )))

PS. "message-message" mode BTW :)
    Of all the things I lost
    I miss my mind the most.

-- 
underground experts united
https://dataswamp.org/~incal