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Subject: Re: [PHP-DEV] Optional interfaces
Date: Fri, 15 Nov 2024 21:27:14 -0300
Message-ID: <BFEF1623-CB82-48DC-8F63-4A649A277222@gmail.com>
References: <b98dc200-02b7-468e-a96d-a38ce10656ed@app.fastmail.com>
Cc: internals@lists.php.net
In-Reply-To: <b98dc200-02b7-468e-a96d-a38ce10656ed@app.fastmail.com>
To: Rob Landers <rob@bottled.codes>
From: deleugyn@gmail.com (=?utf-8?Q?Marco_Aur=C3=A9lio_Deleu?=)


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> On 15 Nov 2024, at 20:42, Rob Landers <rob@bottled.codes> wrote:
>=20
> =EF=BB=BF
>> On Sat, Nov 16, 2024, at 00:34, Juris Evertovskis wrote:
>> Hey all,
>>=20
>> =20
>>=20
>> If you try to implement an interface that does not exist, you get the =E2=
=80=98Interface =E2=80=9C%s=E2=80=9D not found=E2=80=99 error. Usually that=E2=
=80=99s useful as it points to a code error.
>>=20
>> =20
>>=20
>> However, sometimes we want our code to be compatible with an optional lib=
rary. For example, my Expression class might be compatible with some ORM, bu=
t it would also usable without it or with another ORM. This can already be a=
ccomplished, but the solutions seems very workaroundish: https://stackoverfl=
ow.com/questions/57996429/implements-interface-only-if-exists
>>=20
>> =20
>>=20
>> Maybe the PHP itself should allow marking some interfaces as optional =E2=
=80=94 such that they are discarded from the list if the interface class doe=
s not exist? Here=E2=80=99s one way the syntax could look like:
>>=20
>> =20
>>=20
>>     class Expression implements MyInterface, ?OptionalInterface {}
>>=20
>> =20
>>=20
>>     interface EventDispatcherInterface extends ?PsrEventDispatcherInterfa=
ce {}
>>=20
>> =20
>>=20
>> BR,
>>=20
>> Juris
>>=20
>=20
> Hey Juris,
>=20
> Is there some reason you cannot do this:
>=20
> https://3v4l.org/hF1vr
>=20
> =E2=80=94 Rob

That seems to match what he shared on SO link?

I think I opened this email with a strong negative feeling towards what woul=
d be optional interface, but to be honest a syntax sugar where implements ?M=
yInterface becomes something pretty close to what Rob shared doesn=E2=80=99t=
 sound bad, it=E2=80=99s just convenience. Unfortunately PHP is not keen on b=
eing open to those.

Overall, I dig it.=

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<html><head><meta http-equiv=3D"content-type" content=3D"text/html; charset=3D=
utf-8"></head><body dir=3D"auto"><div dir=3D"ltr"><br></div><div dir=3D"ltr"=
><blockquote type=3D"cite">On 15 Nov 2024, at 20:42, Rob Landers &lt;rob@bot=
tled.codes&gt; wrote:<br><br></blockquote></div><blockquote type=3D"cite"><d=
iv dir=3D"ltr">=EF=BB=BF<title></title><div>On Sat, Nov 16, 2024, at 00:34, J=
uris Evertovskis wrote:<br></div><blockquote type=3D"cite" id=3D"qt" style=3D=
"overflow-wrap:break-word;"><div class=3D"qt-WordSection1"><p class=3D"qt-Ms=
oNormal">Hey all,<br></p><p class=3D"qt-MsoNormal">&nbsp;<br></p><p class=3D=
"qt-MsoNormal">If you try to implement an interface that does not exist, you=
 get the =E2=80=98Interface =E2=80=9C%s=E2=80=9D not found=E2=80=99 error. U=
sually that=E2=80=99s useful as it points to a code error.<br></p><p class=3D=
"qt-MsoNormal">&nbsp;<br></p><p class=3D"qt-MsoNormal">However, sometimes we=
 want our code to be compatible with an optional library. For example, my Ex=
pression class might be compatible with some ORM, but it would also usable w=
ithout it or with another ORM. This can already be accomplished, but the sol=
utions seems very workaroundish: <a href=3D"https://stackoverflow.com/questi=
ons/57996429/implements-interface-only-if-exists">https://stackoverflow.com/=
questions/57996429/implements-interface-only-if-exists</a><br></p><p class=3D=
"qt-MsoNormal">&nbsp;<br></p><p class=3D"qt-MsoNormal">Maybe the PHP itself s=
hould allow marking some interfaces as optional =E2=80=94 such that they are=
 discarded from the list if the interface class does not exist? Here=E2=80=99=
s one way the syntax could look like:<br></p><p class=3D"qt-MsoNormal">&nbsp=
;<br></p><p class=3D"qt-MsoNormal">&nbsp;&nbsp;&nbsp; class Expression imple=
ments MyInterface, ?OptionalInterface {}<br></p><p class=3D"qt-MsoNormal">&n=
bsp;<br></p><p class=3D"qt-MsoNormal">&nbsp;&nbsp;&nbsp; interface EventDisp=
atcherInterface extends ?PsrEventDispatcherInterface {}<br></p><p class=3D"q=
t-MsoNormal">&nbsp;<br></p><p class=3D"qt-MsoNormal">BR,<br></p><p class=3D"=
qt-MsoNormal">Juris<br></p></div></blockquote><div><br></div><div>Hey Juris,=
<br></div><div><br></div><div>Is there some reason you cannot do this:<br></=
div><div><br></div><div><a href=3D"https://3v4l.org/hF1vr">https://3v4l.org/=
hF1vr</a><br></div><div><br></div><div id=3D"sig121229152">=E2=80=94 Rob<br>=
</div></div></blockquote><br><div>That seems to match what he shared on SO l=
ink?</div><div><br></div><div>I think I opened this email with a strong nega=
tive feeling towards what would be optional interface, but to be honest a sy=
ntax sugar where implements ?MyInterface becomes something pretty close to w=
hat Rob shared doesn=E2=80=99t sound bad, it=E2=80=99s just convenience. Unf=
ortunately PHP is not keen on being open to those.</div><div><br></div><div>=
Overall, I dig it.</div></body></html>=

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