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Date: Wed, 26 Jun 2024 09:54:58 +0200
To: internals@lists.php.net
Subject: Re: [PHP-DEV] [Early Feedback] Pattern matching
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From: rob@bottled.codes ("Rob Landers")

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On Wed, Jun 26, 2024, at 00:19, Morgan wrote:
> On 2024-06-26 08:24, Rob Landers wrote:
> > On Tue, Jun 25, 2024, at 20:23, Ilija Tovilo wrote:
>=20
> >> If null array values were indeed unobservable, then [] would be =3D=
=3D=3D to
> >> [null] (or at least =3D=3D), and a foreach over [null] would result=
 in 0
> >> iterations. But neither of those are the case.
> >=20
> > I think there is a difference between an empty array and a null, and=20
> > that is (hopefully) self-evident. I=E2=80=99m talking about the infi=
nite nulls=20
> > IN the array. You can write a for loop of all possible keys until th=
e=20
> > end of the universe, and all you will get is null. This is fairly ea=
sy=20
> > to prove. I'll wait... :p
> >=20
> What about the difference between an empty array an an array that=20
> contains a null (Ilija's example)?
>=20
> echo count([]);
> echo count([null]);
> echo count([null, null]);
> echo count([null, null, null]);
> echo count([null, null, null, null]);
> ...
>=20
> You're arguing that these are all the same array?
>=20

If you are accessing them by index, yes, they are all the same array. Th=
ere is no observable difference. I think we already covered that count()=
 would show the difference between them since it=E2=80=99s actually a co=
unt of known indices:

for($i =3D 0; $i < 4; $i++) var_dump([]);

Will output 4 nulls.=20


=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 Wed, Jun 26, 2024, at 00:19, Morgan wrote:<br></div><b=
lockquote type=3D"cite" id=3D"qt" style=3D""><div>On 2024-06-26 08:24, R=
ob Landers wrote:<br></div><div>&gt; On Tue, Jun 25, 2024, at 20:23, Ili=
ja Tovilo wrote:<br></div><div><br></div><div>&gt;&gt; If null array val=
ues were indeed unobservable, then [] would be =3D=3D=3D to<br></div><di=
v>&gt;&gt; [null] (or at least =3D=3D), and a foreach over [null] would =
result in 0<br></div><div>&gt;&gt; iterations. But neither of those are =
the case.<br></div><div>&gt;&nbsp;<br></div><div>&gt; I think there is a=
 difference between an empty array and a null, and&nbsp;<br></div><div>&=
gt; that is (hopefully) self-evident. I=E2=80=99m talking about the infi=
nite nulls&nbsp;<br></div><div>&gt; IN the array. You can write a for lo=
op of all possible keys until the&nbsp;<br></div><div>&gt; end of the un=
iverse, and all you will get is null. This is fairly easy&nbsp;<br></div=
><div>&gt; to prove. I'll wait... :p<br></div><div>&gt;&nbsp;<br></div><=
div>What about the difference between an empty array an an array that&nb=
sp;<br></div><div>contains a null (Ilija's example)?<br></div><div><br><=
/div><div>echo count([]);<br></div><div>echo count([null]);<br></div><di=
v>echo count([null, null]);<br></div><div>echo count([null, null, null])=
;<br></div><div>echo count([null, null, null, null]);<br></div><div>...<=
br></div><div><br></div><div>You're arguing that these are all the same =
array?<br></div><div><br></div></blockquote><div><br></div><div>If you a=
re accessing them by index, yes, they are all the same array. There is n=
o observable difference. I think we already covered that count() would s=
how the difference between them since it=E2=80=99s actually a count of k=
nown indices:<br></div><div><br></div><div>for($i =3D 0; $i &lt; 4; $i++=
) var_dump([]);<br></div><div><br></div><div>Will output 4 nulls.&nbsp;<=
/div><div><br></div><div><br></div><div id=3D"sig121229152">=E2=80=94 Ro=
b<br></div></body></html>
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