Shawn Steele Shawn.Steele at
Tue Dec 1 21:45:04 CET 2009

One example I discussed with Patrik yesterday, was whether locale
might affect mapping. I'd like to get better insight into the general
understanding of that.

> 1. Could locale determine whether a PVALID character should be mapped
> into another PVALID character prior to following the rules to turn
> into an ALABEL?  I believe the consensus answer is probably SHOULD NOT
> or MUST NOT because that would make domains with that valid character
> unreachable by software using those locale rules.

I agree.

> 2. Could locale determine whether, or how, a DISALLOWED character is
> mapped into a PVALID character prior to getting an ALABEL? 

No, for several reasons:

A) If I email you a link that contains a DISALLOWED character, your machine/environment MUST map it to the same thing my machine did.  Otherwise I say "you have funny charges from travelling, visit to correct it."  You are trying to pay for your flight home so you type "" into the computer in the kiosk in the foreign airport, and if it uses different mapping rules you could end up as a phishing site.  You don't want to go to a vı just because you're using a Turkish airport browser.

B) If I travel myself, I need consistent behavior regardless of the machine I'm using.

C) If I see an international advertisement, the domains need to go to the same server, regardless of who and how and where the person is typing in the link.

D) A server or relay wouldn't necessarily know the context the user expected when interpreting a forwarded request.

E) It'd be a support nightmare.

F) I'm not sure if it is practical to create APIs that enable this distinction.  (We (software community, not just my company) already have problems selecting the correct locale specific behavior for sorting and formatting, etc., so we'd be bound to get it wrong at least some of the time.)


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