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Date: Mon, 26 Jan 2026 11:53:50 +0100
Message-ID: <CA+hqhpdOJf-FjZMrxbuq0LvT2UdRwK-_ECSBrSnM7hG0G1HwEg@mail.gmail.com>
Subject: Re: [PHP-DEV] [RFC] Pattern Matching
Cc: internals@lists.php.net
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From: weirdan@gmail.com (Bruce Weirdan)

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On Mon, Jan 26, 2026 at 5:48=E2=80=AFAM Morgan <weedpacket@varteg.nz> wrote=
:

> On 2026-01-26 07:44, Larry Garfield wrote:
> >
> > With per-arm, you can opt-in to pattern matching individually, at the
> cost of having to remember to repeat the keyword on every line.  With
> per-block, you only have to add the keyword once at the cost of not being
> able to selectively use patterns or identity matching.
> >
> > Which tradeoff is better is the option question.  (Ilija and I disagree
> on which to go with.)  Or, if someone can suggest a way to allow automati=
c
> detection reliably, that would also be most welcome. :-)
> >
>
> If it had to be one or the other [...]


Does it have to be one of the other though? Can't we have both?

```php
$result =3D match ($somevar) {
    is Foo =3D> 'foo', // This matches against the pattern `Foo`, which is =
a
class name.
    Bar =3D> 'bar',     // This matches =3D=3D=3D against the constant `Bar=
`, whose
value is whatever.
};
```php

```php
$result =3D match ($somevar) is {
    Foo =3D> 'foo', // This matches against the pattern `Foo`, which is a
class name.
    Bar =3D> 'bar', // This matches against the pattern `Bar`, which is als=
o
a class name
};
```

```php
$result =3D match ($somevar) is {
    is Foo =3D> 'foo', // This is an error (?)
};
```php

We already have somewhat similar behaviour with `readonly` (for properties)
and `abstract` (for methods) class modifiers. When you specify it on a
class, it applies to all members, but you can also specify it on an
individual member.





--=20
  Best regards,
      Bruce Weirdan                                     mailto:
weirdan@gmail.com

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<div dir=3D"ltr"><div dir=3D"ltr"><br></div><br><div class=3D"gmail_quote g=
mail_quote_container"><div dir=3D"ltr" class=3D"gmail_attr">On Mon, Jan 26,=
 2026 at 5:48=E2=80=AFAM Morgan &lt;<a href=3D"mailto:weedpacket@varteg.nz"=
>weedpacket@varteg.nz</a>&gt; wrote:<br></div><blockquote class=3D"gmail_qu=
ote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,20=
4);padding-left:1ex">On 2026-01-26 07:44, Larry Garfield wrote:<br>
&gt; <br>
&gt; With per-arm, you can opt-in to pattern matching individually, at the =
cost of having to remember to repeat the keyword on every line.=C2=A0 With =
per-block, you only have to add the keyword once at the cost of not being a=
ble to selectively use patterns or identity matching.<br>
&gt; <br>
&gt; Which tradeoff is better is the option question.=C2=A0 (Ilija and I di=
sagree on which to go with.)=C2=A0 Or, if someone can suggest a way to allo=
w automatic detection reliably, that would also be most welcome. :-)<br>
&gt; <br>
<br>
If it had to be one or the other [...]</blockquote><div><br></div><div>Does=
 it have to be one of the other though? Can&#39;t we have both?<br><br></di=
v><div>```php</div><div>$result =3D match ($somevar) {<br>
=C2=A0 =C2=A0 is Foo =3D&gt; &#39;foo&#39;, // This matches against the pat=
tern `Foo`, which is a class name.<br>
=C2=A0 =C2=A0 Bar =3D&gt; &#39;bar&#39;,=C2=A0 =C2=A0 =C2=A0// This matches=
 =3D=3D=3D against the constant `Bar`, whose value is whatever.<br>
};</div><div>```php</div><div><br></div><div>```php<br>$result =3D match ($=
somevar) is {<br>=C2=A0 =C2=A0 Foo =3D&gt; &#39;foo&#39;, // This matches a=
gainst the pattern `Foo`, which is a class name.<br>
=C2=A0 =C2=A0 Bar =3D&gt; &#39;bar&#39;, // This matches against the patter=
n `Bar`, which is also a class name<br>
};</div><div>```</div><div><br></div><div><div>```php</div><div>$result =3D=
 match ($somevar) is {<br>
=C2=A0 =C2=A0 is Foo =3D&gt; &#39;foo&#39;, // This is an error (?)<br>};</=
div><div>```php</div><div><br></div><div>We already have somewhat similar b=
ehaviour with `readonly` (for properties) and `abstract` (for methods) clas=
s modifiers. When you specify it on a class, it applies to all members, but=
 you can also specify it on an individual=C2=A0member.</div><div><br></div>=
<br></div><div><br></div></div><div><br clear=3D"all"></div><br><span class=
=3D"gmail_signature_prefix">-- </span><br><div dir=3D"ltr" class=3D"gmail_s=
ignature">=C2=A0 Best regards,<br>=C2=A0 =C2=A0 =C2=A0 Bruce Weirdan=C2=A0 =
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0=C2=A0 mailto:<a href=3D"mailt=
o:weirdan@gmail.com" target=3D"_blank">weirdan@gmail.com</a></div></div>

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