Re: ignoring control characters in character width

[Eli Zaretskii]

> Date: Tue, 5 Sep 2023 20:01:53 +0200
> From: Patrice Dumas <pertusus@free.fr>
> 
> Currently, when counting the width of a line of character, we count
> control characters that are also spaces as having a width of 1.  I think
> that it is not good, as control characters either should not have a
> width, for end of line, form feed, carriage return, or have a width that
> is not well defined for vertical and horizontal tab.  I suggest to
> consider all the control characters as having a width of 0.  This will
> be consistent with libunistring u8_strwidth, which I intend to use in C
> code equivalent to perl code.

Please define "control characters" for this purpose.  Some of them are
definitely not zero-width, for example, TAB.

Also, depending on how control characters are displayed, their width
could be even 4, for example if they are displayed as \nnn octal
escapes.

So I think we need more context for this discussion.