[RFC] Add clamp function #19434

kylekatarnls · 2025-08-09T16:17:34Z

Follow-up #7191

Implementation for the RFC: https://wiki.php.net/rfc/clamp_v2 (see also https://wiki.php.net/rfc/clamp)

clamp(2, min: 1, max: 3) // 2
clamp(0, min: 1, max: 3) // 1
clamp(6, min: 1, max: 3) // 3
clamp(2, 1.3, 3.4) // 2
clamp(2.5, 1, 3) // 2.5
clamp(2.5, 1.3, 3.4) // 2.5
clamp(0, 1.3, 3.4) // 1.3
clamp(M_PI, -INF, INF) // 3.141592653589793
clamp(NAN, 4, 6) // NAN
clamp("a", "c", "g") // "c"
clamp("d", "c", "g") // "d"
clamp(new \DateTimeImmutable('2025-08-01'), new \DateTimeImmutable('2025-08-15'), new \DateTimeImmutable('2025-09-15'))->format('Y-m-d') // 2025-08-15
clamp(new \DateTimeImmutable('2025-08-20'), new \DateTimeImmutable('2025-08-15'), new \DateTimeImmutable('2025-09-15'))->format('Y-m-d') // 2025-08-20

clamp(4, 8, 6)
// Throws ValueError: clamp(): Argument #2 ($min) must be smaller than or equal to argument #3 ($max)

clamp(4, NAN, 6)
// Throws ValueError: clamp(): Argument #2 ($min) cannot be NAN

clamp(4, 6, NAN)
// Throws ValueError: clamp(): Argument #3 ($max) cannot be NAN

Documentation: php/doc-en#4814

ext/standard/tests/math/clamp.phpt

medabkari · 2025-08-09T16:37:33Z

The RFC page status is set to Withdrawn, update it to Draft if you have access.

ext/standard/basic_functions_arginfo.h

kylekatarnls · 2025-08-18T11:30:17Z

Hello @kocsismate and @bukka, any news about this proposal to reconsider clamp RFC?

TimWolla · 2025-08-18T12:27:41Z

@kylekatarnls RFCs are discussed on the mailing list and then need to be voted on. See https://wiki.php.net/rfc/howto for an explanation of the process.

kylekatarnls · 2025-08-18T13:46:07Z

Thanks. I'd like to participate there, but I failed to create a wiki account, the captcha stuff is asking me "To which email address do you have to send an email to now?" and re-reading the whole page, I tried internals@lists.php.net but it's not that, now, I've no idea what it's expecting from me. 😞 Life is hard for humans who failed the Turing test.

TimWolla · 2025-08-18T13:48:05Z

I tried internals@lists.php.net but it's not that, now, I've no idea what it's expecting from me. 😞

That is accurate:

https://github.com/php/web-wiki/blob/0fbb083c530dfa960a73c8cca82193fe4004f00e/dokuwiki/lib/plugins/phpreg/action.php#L87

What error message did you receive?

kylekatarnls · 2025-08-18T15:59:01Z

Thanks for pointing me to the source code of the wiki, my error was The user could not be created. which from source code can have multiple reasons, but mine was that I already have an account (probably created a decade ago 😄) All good now 👍

ext/standard/tests/math/clamp.phpt

ext/standard/math.c

Co-authored-by: thinkverse <hallberg.kim@gmail.com>

ndossche · 2025-11-19T22:25:54Z

ext/standard/math.c

+	Z_FLF_PARAM_ZVAL(2, zmin);
+	Z_FLF_PARAM_ZVAL(3, zmax);
+
+	if (EXPECTED(Z_TYPE_P(zmin) == IS_DOUBLE) && UNEXPECTED(zend_isnan(Z_DVAL_P(zmin)))) {


The current code duplicates the code into the two different implementations.
It would be great to factor this out to a separate function.

Is it all good? I used define assuming it's the most efficient way to share code without affecting runtime performances. Also is the position (just before the actual function) correct regarding conventions for the repository?

I used define assuming it's the most efficient way to share code without affecting runtime performances.

No define, please. Just use a static function for the shared logic and the compiler will figure out whether or not inlining is reasonable (or whether it can just be a tail call or whatever).

Also is the position (just before the actual function) correct regarding conventions for the repository?

Position is fine.

Fully agree to use a proper function instead of defines.
You can pass the implicitly-defined zval *return_value variable to your helper.

ext/standard/math.c

github-actions bot added Extension: standard ABI break labels Aug 9, 2025

kylekatarnls commented Aug 9, 2025

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kylekatarnls force-pushed the feature/clamp branch from a6d8707 to d6f035f Compare August 9, 2025 16:27

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kylekatarnls marked this pull request as ready for review August 10, 2025 09:02

kylekatarnls requested review from bukka and kocsismate as code owners August 10, 2025 09:02

kylekatarnls mentioned this pull request Aug 10, 2025

[RFC] Add clamp function #7191

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kylekatarnls force-pushed the feature/clamp branch from f61c646 to 47446f8 Compare August 10, 2025 09:22

kylekatarnls commented Aug 10, 2025

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This was referenced Aug 10, 2025

Document clamp function php/doc-en#4814

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Document clamp function php/doc-fr#2237

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kylekatarnls force-pushed the feature/clamp branch from 47446f8 to 37cbb4a Compare August 11, 2025 11:47

TimWolla added the RFC label Aug 12, 2025

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alexandre-daubois reviewed Nov 19, 2025

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kylekatarnls mentioned this pull request Nov 19, 2025

[8.6] Add clamp function symfony/polyfill#554

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kylekatarnls force-pushed the feature/clamp branch from 3450a45 to 386cbd4 Compare November 19, 2025 12:38

kylekatarnls force-pushed the feature/clamp branch from 386cbd4 to 240218d Compare November 19, 2025 15:28

kylekatarnls and others added 3 commits November 19, 2025 17:26

Implement clamp function

04dcbf8

Co-authored-by: thinkverse <hallberg.kim@gmail.com>

Improve NAN handling

925a38c

Fix object support for frameless clamp function

c165218

kylekatarnls force-pushed the feature/clamp branch 2 times, most recently from 4606ae5 to 77b8827 Compare November 19, 2025 17:23

ndossche reviewed Nov 19, 2025

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TimWolla reviewed Nov 19, 2025

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Add tests for null and not-comparable cases

4f07c5d

kylekatarnls force-pushed the feature/clamp branch 2 times, most recently from e1bcf76 to 4f07c5d Compare November 20, 2025 10:53

Use a common function for normal and frameless implementations

0a85158

[RFC] Add clamp function #19434

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[RFC] Add clamp function #19434

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