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Date: Mon, 24 Nov 2014 22:28:30 +0000
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To: Sara Golemon <pollita@php.net>
Subject: Re: [PHP-DEV] [RFC] Unicode Escape Syntax
From: ajf@ajf.me (Andrea Faulds)


> On 24 Nov 2014, at 22:21, Sara Golemon <pollita@php.net> wrote:
>=20
> On Mon, Nov 24, 2014 at 2:09 PM, Andrea Faulds <ajf@ajf.me> wrote:
>> Here=E2=80=99s a new RFC: https://wiki.php.net/rfc/unicode_escape
>>=20
> I'm okay with producing UTF-8 even though our strings are technically
> binary.  As you state, UTF-8 is the de-facto encoding, and recognizing
> this is pretty reasonable.

On that note, it strikes me now that we assume an encoding anyway for =
all escape sequences. If I=E2=80=99m using EBCDIC or UTF-16, =E2=80=9C\n=E2=
=80=9D isn=E2=80=99t going to help me much!

> You may want to make it a requirement that strings containing \u
> escapes are denoted as:   u"blah blah"    We set aside this format
> back in the PHP6 days (note that b"blah" is equivalent to "blah" for
> binary strings).

I=E2=80=99d rather keep u"blah blah=E2=80=9D for if/when we add actual =
Unicode strings.=20

> On the BMP versus SMP issue of \uXXXX styles, we addressed this in
> PHP6 by making \u denote 4 hexit BMP codepoints, while \U denoted six
> hexit codepoints.   e.g.    "\u1234" =3D=3D=3D "\U001234"   I'd rather
> follow this style than making \u special and different from hex and
> octal notations by using braces.

That is something I=E2=80=99d thought about. \U takes 8 hex digits in =
every other language which has it, though.

I suppose we could do this, it resolves the BMP issue, certainly. Still, =
I think the brace syntax has its advantages because it=E2=80=99s =
completely unambiguous and it means we only have one syntax for this, =
not two different ones (less mental overhead). Plus, it=E2=80=99s worth =
noting that \u would still be different from \ooo and \xXX anyway, as =
it=E2=80=99d be fixed-length while octal and hex aren=E2=80=99t.

--
Andrea Faulds
http://ajf.me/