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Date: Sat, 31 May 2025 20:36:52 +0900
Message-ID: <CAEPPVa1wmho-YngwYyivUcPny8JCOxfrBDhnnNToicsjQNku0w@mail.gmail.com>
Subject: Re: [PHP-DEV] Adding in a case-insensitive version of str_contains
To: php internals <internals@lists.php.net>
Cc: Nikita Popov <php@npopov.com>, Kamil Tekiela <tekiela246@gmail.com>, 
	Adam Cable <adamcable@gmail.com>
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From: youkidearitai@gmail.com (youkidearitai)

2025=E5=B9=B45=E6=9C=8831=E6=97=A5(=E5=9C=9F) 19:41 Nikita Popov <php@npopo=
v.com>:
>
> On Thu, May 29, 2025, at 23:00, Kamil Tekiela wrote:
>
> As I understand, it was a conscious decision not to add this function
> when str_contains was created. The reason is that case sensitivity is
> locale-dependent, and for such use cases, mbstring extension is better
> [1] & [2]. Do you think that locale is a concern here, and if not,
> why? Would it be a good idea to add mb_str_icontains instead?
>
> If you're going to propose an RFC for this, it would be a good idea to
> explain what the real life use case for it is. While str_contains is
> very useful for checking the existence of a byte-string within another
> byte-string, a case-sensitive check doesn't seem to have much use.
>
> [1]: https://stackoverflow.com/a/63121809/1839439
> [2]: https://wiki.php.net/rfc/str_contains#case-insensitivity_and_multiby=
te_strings
>
>
> To make it a bit more explicit: The proposed str_icontains function does =
not support UTF-8. It would only be case-insensitive on ASCII characters. D=
o we really want to add new functions that do not properly handle UTF-8?
>
> I think that thanks to https://wiki.php.net/rfc/strtolower-ascii (which r=
emoved C locale support from this family of functions), there actually is a=
 pretty viable way forward to make the non-mbstring case-insensitive string=
 functions useful again: Make them work on UTF-8. (In the sense of using Un=
icode case folding and case mapping on UTF-8, while still returning code un=
it offsets. This would make them superior to both the current stri* functio=
ns, and the mb_stri* functions.)
>
> Regards,
> Nikita

Hi,

I agree that it's important to think about it in UTF-8.

I think about UTF-8 support case folding function in past few days.
Maybe... It is like below?

```
grapheme_setlocale($locale);
grapheme_icontains($haystack, $needle);
```

First, grapheme_* function supports locale.
Second, add grapheme_icontains function for case insensitive version
for str_contains. .

What do you think?

Regards
Yuya

--=20
---------------------------
Yuya Hamada (tekimen)
- https://tekitoh-memdhoi.info
- https://github.com/youkidearitai
-----------------------------