On Tue, Jun 25, 2024 at 2:48 AM Larry Garfield <[email protected]> wrote:
>
> On Thu, Jun 20, 2024, at 5:38 PM, Larry Garfield wrote:
>
> > To that end, we're looking for *very high level* feedback on this RFC:
> >
> > https://wiki.php.net/rfc/pattern-matching
>
> Hi folks. Thank you to those who have offered feedback so far. Based on the discussion,
> here's what we're thinking of doing (still subject to change, of course):
>
> * We're going to move as to future-scope. There's enough weirdness
> around it that is independent of pattern matching itself that it will likely require its own
> discussion and RFC, and may or may not involve full pattern support.
>
> * Similarly, we're going to hold off on the weak-mode flag. It sounds like the language
> needs to do more to fix the definition of "weak mode" before it's really viable. :-(
> On the plus side, if the type system itself ever adds support for a "coercion permitted"
> flag, patterns should inherit that naturally, I think.
>
> * Array-application will also be pushed to future-scope. Again, there's enough
> type-system tie in here that is tangential to patterns that we'll pick that fight later.
>
> * Ilija and I have discussed regex patterns a bit further, and it sounds like they’re going
> to be rather complicated to implement. Even assuming we agree on the syntax for it, it would be a
> substantial amount of code to support. (It’s not like types or literals or range where we can
> just drop something pre-existing into a new function.) So we’re going to hold off on this one for
> now, though it does seem like a high-priority follow-up for the future. (Which doesn’t have to be
> us!)
>
> So let's not discuss the above items further at this point.
>
> * I'm going to do some additional research into other languages to see how they handle
> binding vs using variables from scope, and what syntax markers they use and where. Once we have a
> better sense of what is out there and is known to work, we can make a more informed plan for what we
> should do in PHP. (Whether using a variable from scope in the pattern is part of the initial RFC is
> still an open question, but we do need to design it alongside the capture part to ensure they
> don't conflict.) Stay tuned on this front.
>
> * We've removed the dedicated wildcard pattern, as it's equivalent to
> mixed. If there's interest, we're open to having a secondary vote to bring
> it back as a short-hand pattern. It's trivial to implement and we don't have strong
> feelings either way.
>
> * There's not been much discussion of range patterns. Anyone want to weigh in on those?
>
> * The placement of is on match() is still an open question.
>
> * No one has really weighed in on nested patterns for captured variables. Any thoughts there?
>
> * I’ve seen a suggestion for capturing the “rest” of an array when using … That’s an
> interesting idea, and we’ll explore it, though it looks like it may have some interesting
> implications that push it to future scope. It feels like a nice-to-have.
>
> Thanks all.
>
> --Larry Garfield
This morning, while thinking about "new Pattern($pattern)," it
occurred to me: why not create an OOP extension of patterns? It
wouldn't need an RFC or language changes and would allow the
development of patterns to the point where adding it to the core
language may be a no-brainer. You (and other users of it) would have a
pretty good idea of which patterns are actually important and useful
due to actually using them.
It's probably the "long way around" but at that point, you'd basically
just be pulling in the extension and discussing syntax as the behavior
would be well-defined and battle-tested.
Robert Landers
Software Engineer
Utrecht NL