Hi
Am 2025-11-04 03:08, schrieb Ben Ramsey:
In general, I support this RFC. I’d like to see examples from other
programming languages, though. You mention C# and Hack above. Can you
elaborate in the RFC on how they implement this functionality? What
about other programming languages? I know some (Rust maybe?) are scoped
to blocks by default.
Please have a look at Seifeddine's previous reply to Edmond
(https://news-web.php.net/php.internals/129076) and my reply to Arnaud
that I just sent (https://news-web.php.net/php.internals/129087).
There are two things to consider when comparing against other
programming languages. PHP's semantics do not exactly fit any of these,
which means that transferring some concept from another programming
language directly does not work.
1. Scoping:
Many programming languages with explicit variable declarations are block
scoped. This includes Rust (which you correctly mentioned), but also C,
C++, Java, JavaScript (with let and const). Some of them allow shadowing
variables from the scope and some don't.
2. Handling of Lifetimes:
As I mentioned in my reply to Arnaud, PHP is pretty unique in the list
of programming languages with automated memory management in that it
does not primarily use an “unpredictable” garbage collector for memory
management, but instead uses reference counting with reliable destructor
semantics (that are documented). This is different from e.g. Java where
the so-called “finalizers” run at an unpredictable point in time when
the GC feels like cleaning up an object. PHP's semantics are close to
those of C++ (where this kind of memory management is called RAII) or
Rust.
For this reason, PHP just needs some generic “syntactic sugar” for
`unset()` that is compatible with all existing functionality using
`__destruct()` for those RAII semantics.
Best regards
Tim Düsterhus
