On 05/06/2018 08:22, Rudolph Gottesheim wrote:
There's always a lot of talk about types in the PHP community.
Specifically, many developers want property types, generics, function
signature types, union and intersection types, and more. Those talks
(and RFCs) always end with the same result: "We can't do it because
performance issues."
Has there ever been a discussion about adding some of those features
syntactically, but ignoring them during runtime? At least until
someone finds a performant way to check them at runtime. That way we
could have advanced type checking in our editors at least.
Hi,
I believe this is part of the original aim of Hack-Lang: the additional
type features of that language are not part of the run-time, but checked
by a static analysis tool offline. A number of languages have similar
setups - Python and Dart both have the types as offline and/or
development-mode-only features. Indeed, PHP seems to have gone a very
unusual route in having a dynamic language with type constraints which
are effectively always-on assertions.
One of the problems with moving PHP to this offline-checking model is
that people will expect new type constraints to work like existing ones,
so may be caught out by them not being checked at run-time. Worse,
static checks may not be able to detect certain violations; I don't know
much about Hack's model, but I understand it includes both different
levels of strictness, and restrictions on dynamic language features -
things like references, "variable variables", and non-object callables.
I do think it's an interesting question to think about though.
Regards,
--
Rowan Collins
[IMSoP]
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