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Date: Wed, 17 Dec 2025 23:04:21 +0000
To: internals@lists.php.net, =?ISO-8859-1?Q?Tim_D=FCsterhus?= <tim@bastelstu.be>
Subject: =?US-ASCII?Q?Re=3A_=5BPHP-DEV=5D_Examples_comparing_Bl?=
 =?US-ASCII?Q?ock_Scoped_RAII_and_Context_Managers?=
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From: imsop.php@rwec.co.uk ("Rowan Tommins [IMSoP]")

On 17 December 2025 19:59:54 GMT, "Tim D=C3=BCsterhus" <tim@bastelstu=2Ebe>=
 wrote:

>    let (
>        $scoped =3D new Scoped(),
>        $scoped,
>    ) {


My attempts to guess what this would do went something like this:=20

1) The second mention of $scoped does nothing, you've already declared it =
as scoped to this block

2) That seems trivial for the compiler to spot, so probably an Error

3) Maybe it overwrites the variable to null? But that would make the lifet=
ime shorter, not longer

4) So, somehow, there are two variables, with the same name, and they both=
 live until the end of the block?

5) Wait, does that mean this is just a sequence of declaration statements =
in disguise?


It feels like this completely goes against everything you've been saying a=
bout avoiding the ambiguity of ALGOL-style declarations=2E

If you can do that, presumably you can do this:=20

let(
     $foo =3D bar($baz), // What is $baz referring to? Particularly if it =
is a by-reference out parameter=2E
     $baz =3D 1,
 )

Which is a direct translation of an example you gave here: <https://extern=
als=2Eio/message/129059#129583>

Thinking about it, even the dynamic coding features of PHP you say would b=
e so difficult aren't automatically prohibited:=20

let(
    $foo =3D compact('bar'),
    $bar =3D extract($foo),
)
    =20
and so on=2E=20


I kind of hope I'm misunderstanding something here, because this feels lik=
e a pretty big hole in the premise=2E



Rowan Tommins
[IMSoP]