bug#20977: 24.5; Hi Lock Mode fails with "Invalid pattern list expression"

bug#20977: 24.5; Hi Lock Mode fails with "Invalid pattern list expression"

[Raffaele Ricciardi]

This may happen in Help buffers.

Recipe:

emacs -Q
C-h f hi-lock-mode RET
C-x b *Help* RET
M-x hi-lock-mode RET

Emacs says:

Invalid pattern list expression at 60


Thank you.

--

In GNU Emacs 24.5.1 (x86_64-unknown-linux-gnu, GTK+ Version 2.24.25)
  of 2015-06-27 on debian
Windowing system distributor `The X.Org Foundation', version 11.0.11604000
System Description:    Debian GNU/Linux 8.1 (jessie)

Configured using:
  `configure --prefix=/opt/emacs/emacs-24.5-gtk2 --with-x-toolkit=gtk2'

Important settings:
   value of $LANG: en_GB.UTF-8
   locale-coding-system: utf-8-unix

Major mode: Help

Minor modes in effect:
   hi-lock-mode: t
   tooltip-mode: t
   electric-indent-mode: t
   mouse-wheel-mode: t
   tool-bar-mode: t
   menu-bar-mode: t
   file-name-shadow-mode: t
   global-font-lock-mode: t
   font-lock-mode: t
   blink-cursor-mode: t
   auto-composition-mode: t
   auto-encryption-mode: t
   auto-compression-mode: t
   buffer-read-only: t
   line-number-mode: t
   transient-mark-mode: t

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
Loading hi-lock...done
Type C-x 1 to delete the help window, C-M-v to scroll help.
Invalid pattern list expression at 60
  [3 times]
Debug on Error enabled globally
Invalid pattern list expression at 60
Quit

Load-path shadows:
None found.

Features:
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gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util
mail-prsvr mail-utils cus-start cus-load pp hi-lock help-mode easymenu
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bug#20977: 24.5; Hi Lock Mode fails with "Invalid pattern list expression"

[Michael Heerdegen]

Raffaele Ricciardi <rfflrccrd@gmail.com> writes:

> emacs -Q
> C-h f hi-lock-mode RET
> C-x b *Help* RET
> M-x hi-lock-mode RET
>
> Emacs says:
>
> Invalid pattern list expression at 60

AFAIK this is not an error, just a message (that you can safely ignore).
The mode is enabled nonetheless and should work as expected.

Background: There is a feature that hi-lock-mode searches for pattern
specifications of the kind

  Hi-lock: FOO

that define initial highlightings.

Since the help buffer of `hi-lock-mode' explains this feature, it
contains a match for the regexp searched for (namely "Hi-lock: FOO") but
hi-lock-mode discards it because it is invalid (thus the message).  So
this issue is only a coincidence appearing only in the help buffer of
`hi-lock-mode'.  FWIW I can live with this message in this special case,
though I agree that it is confusing.


Michael.

bug#20977: 24.5; Hi Lock Mode fails with "Invalid pattern list expression"

[Raffaele Ricciardi]

On 04/07/15 16:46, Michael Heerdegen wrote:
> Raffaele Ricciardi <rfflrccrd@gmail.com> writes:
>
>> emacs -Q
>> C-h f hi-lock-mode RET
>> C-x b *Help* RET
>> M-x hi-lock-mode RET
>>
>> Emacs says:
>>
>> Invalid pattern list expression at 60
> AFAIK this is not an error, just a message (that you can safely ignore).
> The mode is enabled nonetheless and should work as expected.
>
> Background: There is a feature that hi-lock-mode searches for pattern
> specifications of the kind
>
>    Hi-lock: FOO
>
> that define initial highlightings.
>
> Since the help buffer of `hi-lock-mode' explains this feature, it
> contains a match for the regexp searched for (namely "Hi-lock: FOO") but
> hi-lock-mode discards it because it is invalid (thus the message).  So
> this issue is only a coincidence appearing only in the help buffer of
> `hi-lock-mode'.  FWIW I can live with this message in this special case,
> though I agree that it is confusing.
>
>
> Michael.

I agree that this glitch is not worth fixing.  And if another user will
stumble upon it, he will find this discussion and understand what is
going on.

Thanks, Michael, for your assistance.

bug#20977: 24.5; Hi Lock Mode fails with "Invalid pattern list expression"

[martin rudalics]

 > FWIW I can live with this message in this special case,
 > though I agree that it is confusing.

I suppose we could write something like


When hi-lock is started and if the mode is not excluded or patterns
rejected, the beginning of the buffer is searched for lines of the
form:
   Hi-lock: (FOO BAR)

where FOO and BAR are patterns.


but I don't know what `hi-lock-mode' patterns should look like and how
that mode works.  If anyone does, please apply a patch so we can close
this.

martin

bug#20977: 24.5; Hi Lock Mode fails with "Invalid pattern list expression"

[Lars Ingebrigtsen]

martin rudalics <rudalics@gmx.at> writes:

> I suppose we could write something like
>
> When hi-lock is started and if the mode is not excluded or patterns
> rejected, the beginning of the buffer is searched for lines of the
> form:
>   Hi-lock: (FOO BAR)
>
> where FOO and BAR are patterns.
>
> but I don't know what `hi-lock-mode' patterns should look like and how
> that mode works.  If anyone does, please apply a patch so we can close
> this.

I've now done something like this in Emacs 28.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no