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Date: Thu, 28 Aug 2025 09:37:43 +0200
To: Hans Krentel <hanskrentel@yahoo.de>
Cc: ocramius@gmail.com, Kyle Katarn <kylekatarnls@gmail.com>, PHP Internals
 <internals@lists.php.net>
Subject: Re: [PHP-DEV] [RFC] [Discussion] Add clamp function
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From: tim@bastelstu.be (=?UTF-8?Q?Tim_D=C3=BCsterhus?=)

Hi

Am 2025-08-28 08:35, schrieb Hans Krentel:
> This also highlights a minor but important clarification for the
> documentation. To make the behavior perfectly unambiguous, I suggest
> a small edit to explicitly state the bounds are inclusive.

This is a good point and I agree that it should be spelled out 
explicitly. However to me this also raises the question if the interval 
boundaries should be configurable to switch between closed intervals and 
(half-)open intervals. For many applications of continuous values a 
right-open interval (excluding the upper boundary) is more useful, since 
this makes it easy to generate non-overlapping ranges (e.g. to clamp to 
a given day when passing DateTimeImmutable). This would also provide an 
additional value-add over the min-max construction, where the boundaries 
would need to be calculated manually, which is super complicated to do 
in userland for floats.

There's precedent in ext/random with the Randomizer::getFloat() method 
that takes a Random\IntervalBoundary enum to decide on the the 
interpretation of the boundary values. Translated to `clamp()` this 
could mean:

     $value = 1.0;
     clamp($value, 0.0, 1.0, IntervalBoundary::ClosedOpen); // 
0.999999999999999888978

Best regards
Tim Düsterhus