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Date: Mon, 04 Nov 2024 13:33:32 +0100
To: =?UTF-8?Q?Tim_D=C3=BCsterhus?= <tim@bastelstu.be>,
 "Larry Garfield" <larry@garfieldtech.com>
Cc: "php internals" <internals@lists.php.net>
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Subject: Re: [PHP-DEV] RFC: Support Closures in constant expressions
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From: rob@bottled.codes ("Rob Landers")

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On Mon, Nov 4, 2024, at 13:06, Tim D=C3=BCsterhus wrote:
> Hi
>=20
> Am 2024-10-31 07:16, schrieb Larry Garfield:
> > Hm.  It would never occur to me to use a function for a non-class=20
> > constant in the first place, so I don't know. :-)  Frankly I can't=20
> > recall the last time I used a non-class constant period. :-)
> >=20
> > That said, PHP consts are already a bit squishy, and auto-capture is=20
> > always by value.  That wouldn't give us a loophole?
>=20
> Here's another brainteaser:
>=20
>      function foo(
>          string $bar,
>          Closure $baz =3D static fn () =3D> $bar,
>      ) {
>          var_dump($baz());
>      }
>=20
>      foo('captured');
>=20
> What would you expect the semantics of that script to be?

Isn't this semantically equivalent to:

     function foo(
         string $bar,
         Closure $baz,
     ) {
         $baz =3D static fn () =3D> $bar;
         var_dump($baz());
     }

     foo('captured');

=E2=80=94 Rob
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<!DOCTYPE html><html><head><title></title><style type=3D"text/css">p.Mso=
Normal,p.MsoNoSpacing{margin:0}</style></head><body><div><br></div><div>=
<br></div><div>On Mon, Nov 4, 2024, at 13:06, Tim D=C3=BCsterhus wrote:<=
br></div><blockquote type=3D"cite" id=3D"qt" style=3D""><div>Hi<br></div=
><div><br></div><div>Am 2024-10-31 07:16, schrieb Larry Garfield:<br></d=
iv><div>&gt; Hm.&nbsp; It would never occur to me to use a function for =
a non-class&nbsp;<br></div><div>&gt; constant in the first place, so I d=
on't know. :-)&nbsp; Frankly I can't&nbsp;<br></div><div>&gt; recall the=
 last time I used a non-class constant period. :-)<br></div><div>&gt;&nb=
sp;<br></div><div>&gt; That said, PHP consts are already a bit squishy, =
and auto-capture is&nbsp;<br></div><div>&gt; always by value.&nbsp; That=
 wouldn't give us a loophole?<br></div><div><br></div><div>Here's anothe=
r brainteaser:<br></div><div><br></div><div>&nbsp;&nbsp;&nbsp;&nbsp; fun=
ction foo(<br></div><div>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp=
; string $bar,<br></div><div>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&=
nbsp; Closure $baz =3D static fn () =3D&gt; $bar,<br></div><div>&nbsp;&n=
bsp;&nbsp;&nbsp; ) {<br></div><div>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&=
nbsp;&nbsp; var_dump($baz());<br></div><div>&nbsp;&nbsp;&nbsp;&nbsp; }<b=
r></div><div><br></div><div>&nbsp;&nbsp;&nbsp;&nbsp; foo('captured');<br=
></div><div><br></div><div>What would you expect the semantics of that s=
cript to be?<br></div></blockquote><div><br></div><div>Isn't this semant=
ically equivalent to:<br></div><div><br></div><div>&nbsp;&nbsp;&nbsp;&nb=
sp; function foo(<br></div><div>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbs=
p;&nbsp; string $bar,<br></div><div>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=
&nbsp;&nbsp; Closure $baz,<br></div><div>&nbsp;&nbsp;&nbsp;&nbsp; ) {<br=
></div><div>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;$baz =3D static fn () =3D&=
gt; $bar;</div><div>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; var=
_dump($baz());<br></div><div>&nbsp;&nbsp;&nbsp;&nbsp; }<br></div><div><b=
r></div><div>&nbsp;&nbsp;&nbsp;&nbsp; foo('captured');<br></div><div><br=
></div><div id=3D"sig121229152">=E2=80=94 Rob<br></div></body></html>
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