Re: [DISCUSS] Should RFCs for new functions include a userland polyfill/reference implementation?

Hi Larry, Thanks for the feedback! I completely agree with the "recommended where relevant, but not required" approach. Making it a strict requirement would be an unnecessary blocker for features that simply can't be polyfilled. Your point about benchmarking is spot on. Having a userland implementation gives us a clear baseline to prove that the C implementation actually offers a tangible performance benefit, which is often a key argument in many RFCs. And as you mentioned, it acts as a perfect executable specification to clarify the expected behavior. Given this, do you think it would be worth adding a short note or recommendation to the RFC HOWTO document? Just as a gentle encouragement for future RFC authors to include a userland polyfill (or equivalent PHP logic) when feasible. Best regards, Sepehr در تاریخ سه‌شنبه ۲۵ اوت ۲۰۲۶، ۱۹:۴۴ سپهر محمودی <sepehrphpr@gmail.com> نوشت: > > > در تاریخ سه‌شنبه ۲۵ اوت ۲۰۲۶، ۱۹:۰۸ Larry Garfield > <larry@garfieldtech.com> > نوشت: > >> On Tue, Aug 25, 2026, at 6:18 AM, سپهر محمودی wrote: >> > Hi internals, >> > >> > While reviewing various RFCs that introduce new functions, I noticed an >> > inconsistency: some authors include a userland polyfill (reference >> > implementation) in their RFCs, while others do not. >> > >> > I wanted to open a discussion on whether we should strongly encourage >> > RFC authors to provide a PHP userland implementation when proposing new >> > standard library functions, **where technically feasible**. >> > >> > Of course, I understand that this isn't possible for every new >> > function—especially those that interact with low-level OS APIs, memory >> > management, or internal engine features. However, for functions dealing >> > with arrays, strings, math, or general logic, I believe this has a >> > couple of major benefits: >> > >> > 1. It clarifies the exact intended behavior, including edge cases and >> > type coercions, making the proposal easier to understand without diving >> > into the C implementation. >> > 2. It immensely helps the community (e.g., the Symfony polyfill team) >> > to quickly and accurately port the function to older PHP versions once >> > the RFC is accepted. >> > >> > Should we consider adding this as a standard recommendation (e.g., >> > "Reference Implementation") in the official RFC template for applicable >> > functions? >> > >> > I would love to hear your thoughts on this. >> > >> > Best regards, >> > Sepehr >> >> Interesting idea. I think "recommended where relevant, but not required" >> is a reasonable policy to have. As noted, many RFCs don't have >> polyfillable features. For those where it is feasible, I think the "make >> it clear what the logic is" angle is the most compelling. (I often do that >> in the non-polyfill RFCs to help clarify the behavior.) And it would also >> give us a target to benchmark against to see if putting it in C really has >> a performance benefit. >> >> --Larry Garfield >> > > ---------- > > I'm really glad to see Larry's positive feedback. Looking forward to > hearing more thoughts from everyone else on this. > > Best, > Sepehr > >