Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:129943
Feedback-ID: id5114917:Fastmail
Message-ID: <007ae3ff-2b9c-46da-9513-0c147958b806@rwec.co.uk>
Date: Tue, 27 Jan 2026 15:23:37 +0000
Precedence: list
MIME-Version: 1.0
User-Agent: Mozilla Thunderbird
Subject: Re: [PHP-DEV] [RFC] Deprecate Fuzzy Type Casts and Allow Stringable
 in Strict Mode
To: internals@lists.php.net
References: <CAMU7ir+1VfQCiSVG0BjN5V+upNU2kU+a_rKDXO1=Ahu3ndmOGg@mail.gmail.com>
 <CANS-=pfCasTNSAMSdL8ajJMnrwNpfvbEOoQTQhAQ=X73iG+_tw@mail.gmail.com>
 <CAMU7irLgsMCzHsQDD6Ok2zJZsNyV7LF-PHotzqvSGRAkN9bovg@mail.gmail.com>
 <CANS-=pd2+iqav=VKgON6R6XAs4rodNf+5gCgH=7EUPbTum3wWA@mail.gmail.com>
 <411b1964-eacd-475f-a9f5-2a954b6d30df@app.fastmail.com>
Content-Language: en-GB
In-Reply-To: <411b1964-eacd-475f-a9f5-2a954b6d30df@app.fastmail.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
From: imsop.php@rwec.co.uk ("Rowan Tommins [IMSoP]")

On 27/01/2026 12:13, Rob Landers wrote:
>
> I kinda like this idea, but it would be nice to follow the same rules 
> we have with function calls, thus
>
> int|null $var = "123test"; (https://3v4l.org/C0uaK/rfc#vgit.master)


This comes back to my point about the two-part definition.

You are suggesting that "int|null" should only affect the *input 
interpretation*: "allow null as a valid input, but error on invalid input".

Lynn is suggesting "int|null" should also affect the *output 
behaviour*: "use null as the default output for any invalid input".


This is why I keep thinking about a *family* of cast operations, where 
the *input interpretation* is standardised, but the *output behaviour* 
is selectable by the user.

My current best thought is a generic-style syntax:

must_cast<int>( 'hello' ) // TypeError
try_cast<int>( 'hello', 0 ) // int(0)
can_cast<int>( 'hello' ) // bool(false)

must_cast<int>( null ) // TypeError
try_cast<int>( null, 0 ) // int(0)
can_cast<int>( null ) // bool(false)

must_cast<int|null>( 'hello' ) // TypeError
try_cast<int|null>( 'hello', null ) // null
can_cast<int|null>( 'hello' ) // bool(false)

must_cast<int|null>( null ) // null
try_cast<int|null>( null, null ) // null
can_cast<int|null>( null ) // bool(true)


-- 
Rowan Tommins
[IMSoP]