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Date: Tue, 9 Dec 2014 02:44:33 +0000
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To: mario@include-once.org
Subject: Re: [PHP-DEV] [VOTE][RFC] Unicode Codepoint Escape Syntax
From: ajf@ajf.me (Andrea Faulds)

Hi!

> On 9 Dec 2014, at 02:14, mario@include-once.org wrote:
>=20
> 2014-12-09 0:51 GMT+01:00 Andrea Faulds <ajf@ajf.me>:
>>=20
>> https://wiki.php.net/rfc/unicode_escape
>=20
>=20
> Still leaves unmentioned that there was already an established Unicode
> escape syntax. PCRE provides \x{1F520} for codepoints in conjunction =
to
> plain \xFF for byte escapes.

Interesting, I was unaware of that until now, thanks for pointing this =
out.

> Maybe there should be more elaboration on why PHP itself should go =
with
> the \u{xxxx} ECMAScript representaton, thus introducing a syntax =
disparity
> with our most major string handling extension.

Well, PCRE does what it does probably because of its name: =
*Perl-Compatible* Regular Expressions. Perl has the \x syntax. But =
PCRE=E2=80=99s syntax comes from what suits Perl, not PHP, so I don=E2=80=99=
t see why we should necessarily match its behaviour. If we add \x{xxxxx} =
syntax to PHP=E2=80=99s string literals, then we=E2=80=99ll break =
existing code which uses double quoted strings for regular expressions.

I think \x{xxxx} is misleading anyway - \xXX is always =
single-byte/character, yet Unicode code points can=E2=80=99t be =
represented in PHP strings as single bytes when encoded in UTF-8 (unless =
they=E2=80=99re below U+0100, of course). If I saw "\x{abcd}=E2=80=9D =
I'd expect it to be the same as "\xab\xbc=E2=80=9D. Plus, while Perl has =
\x{xxxx} syntax, Ruby and ECMAScript 6 have the \u{xxxx} syntax, so =
\u{xxxx} is already more popular. The =E2=80=98u=E2=80=99 in \u{xxxx} =
also makes it more obviously =E2=80=9CUnicode=E2=80=9D.

Thanks!
--
Andrea Faulds
http://ajf.me/