New full Unicode for ES6 idea

Peter van der Zee ecma at
Sun Feb 19 01:42:03 PST 2012

Do we know how many scripts actually rely on \uXXXX15 to produce a
stringth length of 3? Might it make more sense to put the new unicode
escape under a different escape? Something like \e for "extended
unicode" for example. Or is this "acceptable migration tax"...

On a side note, if we're going to do this, can we also have aliasses
in regex to parse certain unicode categories? For instance, the es
spec defines the Uppercase Letter" (Lu), "Lowercase Letter" (Ll),
"Titlecase letter" (Lt), "Modifier letter" (Lm), "Other letter" (Lo),
"Letter number" (Nl), "Non-spacing mark" (Mn), "Combining spacing mark
(Mc), "Decimal number" (Nd) and "Connector punctuation" (Pc) as
possible identifier parts. But right now I have to go very out of my
way ( to generate and end up with a 56k script
that's almost pure regex.

This works and performance is amazingly fair, but it'd make more sense
to be able to do \pLt or something, to parse any character in the
"Titlecase letter" category. As far as I understand, these categories
have to be known and supported anyways so these switches shouldn't
cause too much trouble in that regard, at least.

- peter

On Sun, Feb 19, 2012 at 10:17 AM, Axel Rauschmayer <axel at> wrote:
> On Feb 19, 2012, at 9:33 , Brendan Eich wrote:
> Instead of any such *big* new observables, I propose a so-called "Big Red
> [opt-in] Switch" (BRS) on the side of a unit of VM isolation: specifically
> the global object.
> es-discuss-only idea: could that BRS be made to carry more weight? Could it
> be a switch for all breaking changes?
> --
> Dr. Axel Rauschmayer
> axel at
> home:
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> blog:
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