OverStrike control character

[Richard Wordingham]

On Wed, 10 Jun 2020 06:05:57 +0000 (UTC)
abrahamgross--- via Unicode <unicode at unicode.org> wrote:

> 2020/06/10 午前1:45:32 Garth Wallace via Unicode
> <unicode at unicode.org>:
> 
> > Would x OVERSTRIKE z look the same as z OVERSTRIKE x? If yes, would
> > they be considered identical for string matching purposes?  
> 
> They would look the same.
> In a perfect world they would be identical for string matching, but
> since its a new control character I would understand if ppl don't
> want to put in the effort to adopt it properly.
> 
> > Would they have to be reordered for normalization?  
> 
> Not sure what this means, but if I understand it correctly, then this
> might actually be a good idea for collation. But it might also be too
> much effort to implement, so its not necessary. Like the japanese
> saying goes
> “シンプルイズベスト[https://www.weblio.jp/content/Simple+is+Best]”
> 
> > What would be the repercussions for collation?  
> 
> I would say just take the first character in the sequence of
> overstriked characters and use that as the bases of collation. If
> this doesn't work, then I'm always open to suggestions.

But if they're identical for character matching, then they should
collate identically, so this last bit is inherently broken.

Consider <l, OVERSTRIKE, m> and <m, OVERSTRIKE, l> in a proportional
width font.  Are you expecting the rendering system to position the 'l'
using the knowledge that it will be overstruck? Overstriking is
designed for a teletype with fixed width characters. the knowledge that
it will be overstruck?  It takes special effort to get the overstriking
effects on a video terminal or its emulation.

Richard.