Sure. <div><br></div><div>(1) A browser captures a URL from an address bar, and sends it to a backend program, as is. The second process examines it for spoofing issues, and communicates back to the first. Remapping loses information that might be relevant to the user.<div>
<br></div><div><div><div><div>(2) I include <a href="http://ÖBB.at">http://ÖBB.at</a> in this email message. My emailer is IDNA aware, and recognizes this as a URL. I send the email to yours, which is, I presume, also IDNA aware. I don't want either one to lowercase it.</div>
<div><br></div><div>...</div><div><br></div><div>The question to back to you is what concrete problems are solved by making this a MUST.<br><br clear="all">Mark<br>
<br><br><div class="gmail_quote">2009/4/11 John C Klensin <span dir="ltr"><<a href="mailto:klensin@jck.com">klensin@jck.com</a>></span><br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<br>
<br>
--On Saturday, April 11, 2009 08:57 -0700 Mark Davis<br>
<<a href="mailto:mark@macchiato.com">mark@macchiato.com</a>> wrote:<br>
<br>
>...<br>
<div class="im">> I think what we can say is programs SHOULD convert to the<br>
> canonical U-Label form before transmitting to other IDNA-aware<br>
> programs, and to the A-Label form before transmitting to<br>
> non-IDNA-aware programs. (The above isn't formal language, but<br>
> you can see what I mean.)<br>
<br>
</div>Can you identify the use cases for exceptions to this rule<br>
(i.e., what justifies a SHOULD, rather than a MUST) rather than<br>
making the non-conversion behavior non-conforming?<br>
<font color="#888888"><br>
john<br>
<br>
<br>
</font></blockquote></div><br></div></div></div></div></div>