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Date: Fri, 22 Aug 2025 15:09:11 -0500
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Subject: Re: [PHP-DEV] [RFC] Add clamp function
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From: larry@garfieldtech.com ("Larry Garfield")

On Fri, Aug 22, 2025, at 12:45 PM, Kyle Katarn wrote:

> About "What determines comparability", it follows the usual rules of 
> PHP: https://www.php.net/manual/en/language.operators.comparison.php
>
> So it's equivalent to ($value < $min) ? $min : (($value > $max) ? $max 
> : $value) and also equivalent to min($max, max($min, $value))
>
> About clamp(new Point(1, 2), new Point(0, 0), new Point(5, 5));
>
> If Point is a comparable value (simple DTO for example), it should 
> return $value, like when doing ($value < $min) ? $min : (($value > 
> $max) ? $max : $value) we could add a test for such case, but I think 
> that for consistency, whatever currently works in min() should work in 
> clamp()
>
> Following the link of the implementation, there is also a link to the 
> documentation where I already explained the comparison rules following 
> the example of what was done in the documentation for min() and max(): 
> https://github.com/php/doc-en/pull/4814

Please make sure the above is captured in the RFC.

Though apparently what PHP currently does with Point comparisons in min/max is... weird.  I don't even know what the logic here is. :)

https://3v4l.org/pTmiV

(No need to change it in this RFC, just note explicitly that the expected behavior is identical to that min(max()) construct, regardless of type.)

--Larry Garfield