[debbugs-tracker] bug#1042: closed (23.0.60; read-char can evaluate to non-character)

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Your message dated Mon, 10 Sep 2018 13:01:11 +0300
with message-id <address@hidden>
and subject line Re: bug#32562: 26; `read-char(-exclusive)' and `characterp'
has caused the debbugs.gnu.org bug report #32562,
regarding 23.0.60; read-char can evaluate to non-character
to be marked as done.

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32562: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=32562
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> --- Begin Message ---
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> Subject: 
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> 23.0.60; read-char can evaluate to non-character
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> Date: 
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> Sun, 28 Sep 2008 07:09:36 +0200 (CEST)
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> In "$ emacs -Q", when I evaluate:
>
>    (read-char)
>
> and press C-0, I get:
>
>    67108912
>
> However, (characterp 67108912) is nil, and (char-to-string 67108912)
> throws an error. Thus I expect an error also from read-char in this
> case. Besides, in `char-resolve-modifers', "modifiers" is misspelled.
>
> In GNU Emacs 23.0.60.1 (i386-apple-darwin8.11.1, GTK+ Version 2.12.9)
>  of 2008-09-24 on mt-computer.local
> Windowing system distributor `The XFree86 Project, Inc', version 11.0.40400000
> Important settings:
>   value of $LC_ALL: nil
>   value of $LC_COLLATE: nil
>   value of $LC_CTYPE: nil
>   value of $LC_MESSAGES: nil
>   value of $LC_MONETARY: nil
>   value of $LC_NUMERIC: nil
>   value of $LC_TIME: nil
>   value of $LANG: en_GB.UTF-8
>   value of $XMODIFIERS: nil
>   locale-coding-system: nil
>   default-enable-multibyte-characters: t
>
>
>
>
> --- End Message ---
> --- Begin Message ---
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> Subject: 
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> Re: bug#32562: 26; `read-char(-exclusive)' and `characterp'
>
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>
>
> Date: 
>
> Mon, 10 Sep 2018 13:01:11 +0300
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>
>
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> > Date: Tue, 28 Aug 2018 14:24:36 -0700 (PDT)
> > From: Drew Adams <address@hidden>
> > Cc: address@hidden
> > 
> > is `read-char' necessarily about chars that satisfy `characterp'?
>
> No.  It returns a character event, not a character.
>
> > The doc string of `text-char-description' says "file-character CHARACTER". 
> > What's a "file character"? A character that can appear in a file name?
>
> No, text-char-description accepts only valid character codes, those
> which satisfy the 'characterp' test.  This is unlike
> single-key-description, which accepts _events_, and thus will happily
> process character input events that are not valid character codes,
> i.e. fail the 'characterp' test.  I've now made that clear in the
> respective doc strings.
>
> > This stuff is not clear more generally, I think - beyond the max value of 
> > `max-char'. Do we have or want to have different kinds of "characters" 
> > returned from or passed as args to different "character" functions? Why (or 
> > why not)?
>
> The basic difference is between a character code and a character input
> event.
>
> > Wrt my original problem: taking a value of `M-:' from `read-char' and passing 
> > it to `text-char-description', Emacs has a regression of sorts. Older Emacs 
> > versions "work", whereas recent versions raise an error. E.g. Emacs 20 
> > `read-char' returns -134217670, and passing that to `text-char-description' 
> > gives "\272". Whatever `read-char' can read, it seems, 
> > `text-char-description' can describe (perhaps imperfectly?).
>
> It's not a regression: text-char-description wants a valid character
> code.
>
> I'm closing this bug, as I think this is a documentation issue which
> is now fixed.
>
> Thanks.
>
>
> --- End Message ---