[PHP-DEV] [DISCUSS] Should RFCs for new functions include a userland polyfill/reference implementation?

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