[UA-discuss] [UA-EAI] Issue needs discussion and closure

[Arnt Gulbrandsen]

Mark Svancarek via UA-EAI writes:
> Discussing with Dennis, we wonder if M3AAWG already has a 
> recommendation on this topic.  If so, we should adopt theirs.

Well, there already is a source of truth, you can see it if you look down: 
Your keyboard.

I don't know where each of you are in the world, but the keyboard, whatever 
it is, provides strong guidance (even if not an absolute rule) on what sort 
of identifiers you and your correspondents can use.

I know you (Mark/Dennis) thought about it more generally. Achoring the 
question to the keyboard can help segment the general question into 
usefully concrete ones, though.

The rule (or each part-rule of there are several) can be stricter then the 
keyboard, can map the keyboarding ability exactly, or can be laxer.

1. Should there be any sort of general rule that restricts identifiers more 
than keyboards do? (Some such rules do exist, e.g. "can't have @ in a 
localpart" or "can't practically have space in a localpart".) IMO we cannot 
and should not expect anything on people's keyboards today to be useless or 
harmful, therefore we should not add rules to block anything.

2. Or that describes exactly, o so that email providers can enforce that 
people can enter only what their keyboards permit, and nothing else? 
Personally I don't see the point. A lot of tedious work and what will it 
achieve? Please don't answer "block confusing glyphs", because а@gamil.com 
and a at gmail.com may be confusable, but gamil and gmail aren't going to 
coordinate anyway.

3. Or be laxer? For example: "Software and sites SHOULD support all of the 
following code points in localparts: τυφχψωϊϋόύώϙϛϝϟϡϸ… Sites SHOULD allow 
users to include any code points from that list, if they permit user choice 
at all." I don't see the point either. It's the kind of rule people ignore.

Arnt