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Subject: [PHP-DEV] Optional interfaces
Date: Sat, 16 Nov 2024 01:34:02 +0200
Message-ID: <0a2f01db37b6$daba4e60$902eeb20$@glaive.pro>
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From: juris@glaive.pro ("Juris Evertovskis")

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Hey all,

 

If you try to implement an interface that does not exist, you get the
'Interface "%s" not found' error. Usually that's useful as it points to a
code error.

 

However, sometimes we want our code to be compatible with an optional
library. For example, my Expression class might be compatible with some ORM,
but it would also usable without it or with another ORM. This can already be
accomplished, but the solutions seems very workaroundish:
https://stackoverflow.com/questions/57996429/implements-interface-only-if-ex
ists

 

Maybe the PHP itself should allow marking some interfaces as optional - such
that they are discarded from the list if the interface class does not exist?
Here's one way the syntax could look like:

 

    class Expression implements MyInterface, ?OptionalInterface {}

 

    interface EventDispatcherInterface extends ?PsrEventDispatcherInterface
{}

 

BR,

Juris


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link=3D"#467886" vlink=3D"#96607D" style=3D'word-wrap:break-word'><div =
class=3DWordSection1><p class=3DMsoNormal>Hey all,<o:p></o:p></p><p =
class=3DMsoNormal><o:p>&nbsp;</o:p></p><p class=3DMsoNormal>If you try =
to implement an interface that does not exist, you get the =
&#8216;Interface &#8220;%s&#8221; not found&#8217; error. Usually =
that&#8217;s useful as it points to a code error.<o:p></o:p></p><p =
class=3DMsoNormal><o:p>&nbsp;</o:p></p><p class=3DMsoNormal>However, =
sometimes we want our code to be compatible with an optional library. =
For example, my Expression class might be compatible with some ORM, but =
it would also usable without it or with another ORM. This can already be =
accomplished, but the solutions seems very workaroundish: <a =
href=3D"https://stackoverflow.com/questions/57996429/implements-interface=
-only-if-exists">https://stackoverflow.com/questions/57996429/implements-=
interface-only-if-exists</a><o:p></o:p></p><p =
class=3DMsoNormal><o:p>&nbsp;</o:p></p><p class=3DMsoNormal>Maybe the =
PHP itself should allow marking some interfaces as optional &#8212; such =
that they are discarded from the list if the interface class does not =
exist? Here&#8217;s one way the syntax could look like:<o:p></o:p></p><p =
class=3DMsoNormal><o:p>&nbsp;</o:p></p><p =
class=3DMsoNormal>&nbsp;&nbsp;&nbsp; class Expression implements =
MyInterface, ?OptionalInterface {}<o:p></o:p></p><p =
class=3DMsoNormal><o:p>&nbsp;</o:p></p><p =
class=3DMsoNormal>&nbsp;&nbsp;&nbsp; interface EventDispatcherInterface =
extends ?PsrEventDispatcherInterface {}<o:p></o:p></p><p =
class=3DMsoNormal><o:p>&nbsp;</o:p></p><p =
class=3DMsoNormal>BR,<o:p></o:p></p><p =
class=3DMsoNormal>Juris<o:p></o:p></p></div></body></html>
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