> Greetings internals,
>
> I present to you a proposal for a new basic math function: clamp.
>
> The main goal of this function is to contain a number inside a given bound.
> And return the number if it is inside of that bound, and if not, and the
> number is outside of the given bound, the nearest bound is returned.
>
> Now, does this need an RFC? The behaviour can be implemented in userland
> in a number of ways, one of which is to compare the values in a if statement.
> Another is to use the min and max math functions.
>
> max($min, min($max, $num));
>
> I don’t have any schpeel as to why this should be in core, only that I
> thought it already was.
> Considering it is part of other languages standard math library, and it is a
> useful function.
>
> Can see this being useful in image manipulation, server-side rendering and
> math just to name few.
>
> The proposed signature follows the convention of other math related functions.
>
> function clamp(int|float $num, int|float $min, int|float $max): int|float {}
>
> This function is very easy to implement, has no side effects or backward
> compatibility issues, unless a userland implementation already has the
> function declared,
> in which case PHP will throw a fatal error since the function cannot be
> redeclared.
>
> I've implemented this feature a few months ago already.
> - Link: https://github.com/thinkverse/php-src/pull/1
> <https://github.com/thinkverse/php-src/pull/1>
>
> What are your opinions on this function?
>
> Regards,
> Kim Hallberg.
+1 from me as well.
We recently added `str_contains`/`starts_with`/`ends_with`, which were
welcome additions. I think `clamp` would be a nice addition too.
I found three user-land `clamp` function declarations on a search on
GitHub public repos.
-
[doubleleft/hook](https://github.com/doubleleft/hook/blob/master/src/bootstrap/helpers.php#L129)
- 764 stars, Last activity in 2016.
-
[GetSimpleCMS/GetSimpleCMS](https://github.com/GetSimpleCMS/GetSimpleCMS/blob/master/admin/inc/basic.php#L2489)
- 336 stars, Has recent activity.
-
[shish/shimmie2](https://github.com/shish/shimmie2/blob/master/core/polyfills.php#L477)
- 267 stars, Has recent activity.
I think it's safe to say that these libraries will be updated to
accommodate the `clamp` function in PHP core; I'd even happily send
pull requests to them. `doubleleft/hook` probably wouldn't be updated
because it doesn't show recent activity, but that's an acceptable BC
impact for a nice addition IMO.
Thank you,
---
Ayesh.
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