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Date: Tue, 8 Jun 2010 15:57:25 +0100
Message-ID: <93ED589E60BA254F97435FE6C97F2C670A96E32C@leedsmet-exch1.leedsmet.ac.uk>
In-Reply-To: <C091E733-D1CE-4494-A176-9B6E878C5ACA@oettinger.dk>
Thread-Topic: [PHP-DEV] [RFC] Array Dereferencing
Thread-Index: AcsHDDjUvRs9OfULTpOFMzrFvqSP+AAC5X8Q
References: <AANLkTik41Xs6rP2TAwWn0PfKpy3H31OZ47KtfrfpI09S@mail.gmail.com> <2C70277E-0442-49B8-AD0B-E9F12ED7B42C@oettinger.dk> <1275993681.2243.10.camel@guybrush> <C091E733-D1CE-4494-A176-9B6E878C5ACA@oettinger.dk>
To: "internals" <internals@lists.php.net>
Subject: RE: [PHP-DEV] [RFC] Array Dereferencing
From: M.Ford@leedsmet.ac.uk ("Ford, Mike")

> -----Original Message-----
> From: Jacob Oettinger [mailto:jacob@oettinger.dk]
> Sent: 08 June 2010 14:09
>=20
> On 08/06/2010, at 12.41, Johannes Schl=FCter wrote:
>=20
> > On Tue, 2010-06-08 at 12:23 +0200, Jacob Oettinger wrote:
> >> Would it be equally simple to allow the syntax below?
> >>
> >> $result =3D new ResultMaker()->getIt();
> >
> > does this mean
> >
> >    $result =3D new (ResultMaker()->getIt());
> >
> > or
> >
> >    $result =3D (new ResultMaker())->getIt();
> >
> > I assume the later, but that is non-obvious as we allow
> >
> >    $result =3D new $class();
>=20
> Yes the later. I do not see how the above makes it non-obvious.

I think the only problem with deciding which it means is that -> and () are=
 not defined as operators in the PHP documentation, and as such do not have=
 a clearly-defined precedence and associativity. In Javascript, "." (proper=
ty access) and "()" (function call) both appear in the operator precedence =
table, so there are definite rules for ascertaining the meaning of such a c=
onstruct.

Up until recently this probably hasn't really been a problem, as it's not b=
een possible to write constructs that needed these rules to decipher them. =
However, with the previous addition of object access chaining, and now arra=
y dereferencing, the time has almost certainly come to add -> and () to the=
 operator documentation, with appropriate precedence and associativity.

(Incidentally, other operators which are not documented in the "Operators" =
section, and probably should be, include :: (which *is* described in the "C=
lasses and Objects" section as the "Scope Resolution Operator", and \ (name=
space separator).)

Cheers!

Mike
 --=20
Mike Ford,
Electronic Information Developer, Libraries and Learning Innovation,=20=20
Leeds Metropolitan University, C507, Civic Quarter Campus,=20
Woodhouse Lane, LEEDS,=A0 LS1 3HE,=A0 United Kingdom=20
Email: m.ford@leedsmet.ac.uk=20
Tel: +44 113 812 4730




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