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Re: Recent history of vi

From	antispam@fricas.org (Waldek Hebisch)
Newsgroups	comp.os.linux.misc, alt.folklore.computers
Subject	Re: Recent history of vi
Date	2025-12-16 02:20 +0000
Organization	To protect and to server
Message-ID	<10hqfll$2g7ff$1@paganini.bofh.team> (permalink)
References	(7 earlier) <10ga6r1$7ph$1@news.misty.com> <slrn10ik3r5.2dppt.als@mordor.angband.thangorodrim.de> <10gpatq$jpt$3@news.misty.com> <10gpi2s$3cij2$2@dont-email.me> <10hoktv$o38$1@news.misty.com>

Cross-posted to 2 groups.

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In alt.folklore.computers Johnny Billquist <bqt@softjar.se> wrote:
<snip>
>> The biggest problem I have with any Unicode representation except (I 
>> think) UTF-32 is that a program has no way of knowing how long a string 
>> is without encoding/decoding it. Given a string of characters in some 
>> codepage, how many bytes does it occupy when converted to UTF-8? Given a 
>> UTF-8 character string, how many character positions does it occupy, 
>> say, for example, when displayed on a screen?
> 
> True. However, that has nothing to do with Unicode as such, but the 
> UTF-8 encoding of it.

Unicode has combining "characters", so to know how many "real"
character you have you need to combine.  IIUC for Korean Hangul 
character can be buit from 3 separate pieces, each taking one code
point, but also there are "precomposed" combinations taking a
single code point.  My reading of description is that 3 pieces
version and precomposed one are supposed to display the same.

There are also code point for ligatures, for most puproses ligature 
fi' counts as two characters, but is a single code point.  Terminal
may display it in a single cell, but arguably for noice monspaced
display one should expand ligatures.  For display we have single
cell characters and double width one, so to know width one needs
at least table giving width of codepoint and add widths of all
codepoints.

-- 
                              Waldek Hebisch

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Re: Recent history of vi Johnny Billquist <bqt@softjar.se> - 2025-12-15 10:38 +0100
  Re: Recent history of vi antispam@fricas.org (Waldek Hebisch) - 2025-12-16 02:20 +0000
    Re: Recent history of vi Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-12-16 02:52 +0000
    Re: Recent history of vi Nuno Silva <nunojsilva@invalid.invalid> - 2025-12-16 11:53 +0000
      Re: Recent history of vi Richard Kettlewell <invalid@invalid.invalid> - 2025-12-16 17:42 +0000
    Re: Recent history of vi Johnny Billquist <bqt@softjar.se> - 2025-12-17 10:39 +0100
  Re: Recent history of vi "Carlos E.R." <robin_listas@es.invalid> - 2025-12-16 23:34 +0100
    Re: Recent history of vi Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-12-17 01:49 +0000

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