bug#51733: 27.1; Detect impossible email addresses better

[Eli Zaretskii]

On January 17, 2022 10:59:36 AM GMT+02:00, Lars Ingebrigtsen <larsi@gnus.org> 
wrote:
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> So I guess the Scripts.txt file will have to be parsed in addition, and
> >> into a new char table.
> >
> > Why can't we use our char-script-table? how different is it from what
> > Unicode wants?
> 
> Well, as the Unicode web page says -- using Blocks to determine the
> script is just, well, wrong.  (Or "inaccurate", if you want.)  So using
> it will give both false positives and negatives.

Yes, I understand the general concern, but I'm asking how serious is this in 
practice.  Can you tell?

> In addition, that table assumes that each character belongs to a single
> script, which is also wrong.  So I'm making a new table based on
> Scripts.txt and ScriptExtensions.txt.

It is confusing to have 2 separate properties of a character that are subtly 
incompatible, and for such obscure properties at that.  It will be source of 
many problems.  So I think we should avoid that if it's feasible.  Can we 
plrase discuss any real problems that would be xaused by using the existing 
char-table?