Full Unicode strings strawman

[Shawn Steele]

> > myString.replace( /[\ud800-\udbff](?![\udc00-\uffff])/g, "\ufffd")
> >    .replace( /(^|[^\ud800-\udbff])([\udc00-\udffff])/g, "\ufffd")

> Exactly as it currently does, assuming it was applied to a string that didn't contain any codepoints greater than \uffff. 
> If the string contained any codepoints > \uffff those character would not match the pattern should be replaced.

Isn't that breaking?  I'm not sure how you can treat these characters distinctly as some code point from d800-dfff sometimes and as a codepoint > 0xffff at other times.

-Shawn