Re: [RFC] Desire to move RFC add_str_begin_and_end_functions to a vote

From: Date: Fri, 28 Jun 2019 20:54:49 +0000
Subject: Re: [RFC] Desire to move RFC add_str_begin_and_end_functions to a vote
References: 1 2 3 4 5 6 7 8  Groups: php.internals 
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These are good points. Originally my RFC called for less functions but based on feedback I added the others. My proposal: take the RFC as-is to a vote. If it fails, I will raise another RFC for a vote that will just contain the two basic functions: str_begins and str_ends. Thanks, Will On 2019-06-22 15:56, Ben Ramsey wrote:
On Jun 22, 2019, at 10:32, Nikita Popov <nikita.ppv@gmail.com> wrote:
On Thu, Jun 20, 2019 at 12:32 AM <will@wkhudgins.info> wrote: I sent this earlier this week without [RFC] in the subject line...since some people might have filters to check the subject line I wanted to send this again with the proper substring in the subject line–to make it clear I intend to take this to a vote in two weeks. Apologies for the duplicate email. -Will
On 2019-06-18 14:45, will@wkhudgins.info wrote: Hello all, I submitted this RFC several years ago. I collected a lot of feedback and I have updated the RFC and corresponding github patch. Please see the RFC at https://wiki.php.net/rfc/add_str_begin_and_end_functions and the github patch at https://github.com/php/php-src/pull/2049. I have addressed many concerns (order of arguments, name of functions, multibye support, etc). I plan to move this RFC to a vote in the coming weeks. Thanks, Will
Unfortunately, this looks like a case where the RFC feedback has made the proposal worse, rather than better :( I think it's easier to start with what I think this proposal should be: There should be just two functions, str_starts_with() and str_ends_with() -- and that's it. The important realization to have here is that these functions are a bit of sugar for an operation that is quite common, but can also be easily implemented with existing functions (using strcmp, strpos or substr, depending on what you like). There is no need for us to cover every conceivable combination, just make the common case more convenient and easier to read. With that in mind: * I believe the "starts with" and "ends with" naming is a lot more canonical, used by Python, Ruby, Java, JavaScript and probably lots more. * In my experience case-insensitive "i" variants of strings functions are used much less, by an order of magnitude. With this being sugar in the first place, I don't think there's a need to cover case-insensitive variations (and from a quick look, these don't seem to be first class methods in other languages either). If we do want to have them, I'd suggest making the names str_starts_with_ci() and str_ends_with_ci(), which is more obvious and harder to miss than str_istarts_with() etc. * Having mb_* variants of these functions doesn't really make sense. I realize that there's this knee-jerk reaction about how if it doesn't have "mb" in the name it's not Unicode compatible, but in this case it's even more wrong than usual. The normal str_starts_with() function is perfectly safe to use on UTF-8 strings, the only difference between it and mb_str_starts_with() is that it's going to be implemented a lot more efficiently. The only case that *might* make some sense is the case-insensitive variant here, because that has some genuine reliance on the character encoding. But then again, this can be handled by case-folding the strings first, something that mbstring is going to do internally anyway. I would happily accept a proposal for str_starts_with() + str_ends_with(), but I'm a lot more apprehensive about adding these 8 new functions. Regards, Nikita
I like the idea of simplifying this to the two functions str_starts_with() and str_ends_with(). When I was looking through this the other day, I had trouble coming up with an example of a string with the mb_* versions would ever generate a different result from the non-multibyte versions, since the implementation only needs to count and analyze bytes for uniqueness. Perhaps it would only be an issue with the case-insensitive versions, as Nikita points out? If so, can someone provide some example strings where an mb_starts_with_ci() would return true, while str_starts_with_ci() would return false? I think the case sensitivity versions would be common enough in use cases (i.e. looking to see if a path ends with .CSV vs. .csv, etc.), but maybe the signatures could be revised to pass a third parameter? str_starts_with($haystack, $needle, $case_sensitive = true): bool -Ben


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