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Date: Sun, 25 Aug 2024 10:04:20 -0400
To: Bilge <bilge@scriptfusion.com>
Cc: "=?utf-8?Q?internals=40lists.php.net?=" <internals@lists.php.net>
Message-ID: <E7303985-17AE-461E-94F1-A14B24DC07A7@getmailspring.com>
In-Reply-To: <0c8ed5d6-5507-4c41-8d7f-05d14ba8aa4c@scriptfusion.com>
References: <0c8ed5d6-5507-4c41-8d7f-05d14ba8aa4c@scriptfusion.com>
Subject: Re: [PHP-DEV] [RFC] Default expression
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From: john@coggeshall.org (John Coggeshall)

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On Aug 24 2024, at 12:49 pm, Bilge <bilge@scriptfusion.com> wrote:
> Hi gang,
>
> New RFC just dropped: https://wiki.php.net/rfc/default_expression. I
> think some of you might enjoy this one. Hit me with any feedback.
>

Seems like you are missing an option for your theme example, which would be to simply extend the Config class?
While I can see the value in the concept of default , I think it's a mistake to allow default to be used as a generic operand as shown in the RFC appendix. It seems to me that the whole point of something like default is to not have to worry about what the upstream API wanted for that value, but the second you start allowing operations where default is an operand you've reintroduced the problem you were trying to avoid if the upstream API were to change the type of what default ultimately resolves to. Worse actually because now I have no idea what default is when I read code without having to dig up the upstream API.
Other thoughts here are what happens when default resolves to an object or enumeration or something complex? Your original example had CuteTheme , so can you call a method of default ?? I could entirely see someone doing something like this for example:
enum Foo:string {
// cases

public function buildSomeValidBasedOnCase(): int { // ... }
}

F(MyClass::makeBasedOnValue(default->buildSomeValidBasedOnCase()))
IMO most operators listed in the appendix should be disallowed. I can see the value of default | JSON_PRETTY_PRINT, but I am pretty strongly opposed to the idea of introducing a "conditional based on the default value of an upstream API call" concept of default >=1 .


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<br><br><div class=3D=22gmail=5Fquote=5Fattribution=22>On Aug 24 2024, at=
 12:49 pm, Bilge &lt;bilge=40scriptfusion.com&gt; wrote:</div><blockquote=
><div><div>Hi gang,</div><br><div>New R=46C just dropped: https://wiki.ph=
p.net/rfc/default=5Fexpression. I</div><div>think some of you might enjoy=
 this one. Hit me with any feedback.</div><br></div></blockquote><div><br=
><div>Seems like you are missing an option for your theme example, which =
would be to simply extend the <code>Config</code>&nbsp; class=3F</div><br=
><div>While I can see the value in the concept of <code>default</code>&nb=
sp;, I think it's a mistake to allow <code>default</code>&nbsp; to be use=
d as a generic operand as shown in the R=46C appendix. It seems to me tha=
t the whole point of something like <code>default</code>&nbsp; is to not =
have to worry about what the upstream API wanted for that value, but the =
second you start allowing operations where <code>default</code>&nbsp; is =
an operand you've reintroduced the problem you were trying to avoid if th=
e upstream API were to change the type of what <code>default</code>&nbsp;=
 ultimately resolves to. Worse actually because now I have no idea what <=
code>default</code>&nbsp; is when I read code without having to dig up th=
e upstream API.</div><br><div>Other thoughts here are what happens when <=
code>default</code>&nbsp; resolves to an object or enumeration or somethi=
ng complex=3F Your original example had <code>CuteTheme</code>&nbsp;, so =
can you call a method of <code>default</code>&nbsp;=3F=3F I could entirel=
y see someone doing something like this for example:</div><br><div>enum =46=
oo<span data-emoji-typing=3D=22true=22>:string</span>&nbsp;=7B</div><div>=
&nbsp;&nbsp;&nbsp; // cases</div><br><div>&nbsp;&nbsp;&nbsp; public funct=
ion buildSomeValidBasedOnCase(): int =7B // ... =7D</div><div>=7D</div><b=
r><div>=46(MyClass:<span data-emoji-typing=3D=22true=22>:makeBasedO</span=
>nValue(default-&gt;buildSomeValidBasedOnCase()))</div><br><div>IMO most =
operators listed in the appendix should be disallowed. I can see the valu=
e of <code>default =7C JSON=5FPRETTY=5FPRINT,</code>&nbsp; but I am prett=
y strongly opposed to the idea of introducing a =22conditional based on t=
he default value of an upstream API call=22 concept of <code>default &gt;=
=3D1</code>&nbsp;.</div><br><br></div>
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