On 06/10/2016 11:57 AM, Rowan Collins wrote:
On 10/06/2016 17:16, Larry Garfield wrote:
That seems like a worthwhile trade-off for a <1% performance difference
in a real-world application.
The problem is that the performance hit is felt even for code that
doesn't "opt in" to this feature. For an application that makes no use
of the feature, it is all cost and no benefit.
I think PHP is at a cross-roads, and (if you'll forgive the stretched
analogy) at risk of going off-road and getting stuck in the mud.
Option 1 is that the language remains inherently loose-typed, with a
few entirely optional features to provide type safety in specific
cases. If this is the aim, then the optional features should be as
unobtrusive as possible for the "default" loose-typed approach. Any
performance hit on untyped properties is a big deal under this
interpretation.
Option 2 is that the language embraces "gradual typing" as a core
tenet of the language, with loose typing considered a "fallback". If
this is the aim, then there should be a coherent roadmap of what the
type system is going to look like. In this case, performance issues
might be considered an inevitable cost of improving the language; they
might also be reduced as the Engine is adapted to implement the roadmap.
Option 1 seems more appealing, because it is easier to get agreement
for, but if we keep piling on the special cases, we're going to end up
with the worst of both worlds. I see the technical problems with
creating a reference to a typed property as a sign of this: we are
creating more of the frustrating inconsistencies that PHP is infamous
for, because we're trying to have our cake and eat it.
For the record, I'm not entirely sure which way I want the language to
go, but I think it's a decision that needs to be made, and soon.
Regards,
This is a very accurate and well-stated assessment. I agree with the
possible paths.
From the code I see in the wild, it feels like the gradually/mostly
typed camp has already won in terms of production code. Most of the PHP
Rennaissance-era systems (the stuff that came out in the last 5-6 years
or so) is class-heavy and as type safe as PHP has allowed, most of the
time. The exceptions are the highly functional bits, where the language
doesn't offer as much support as it does for class-family typing.
There's almost certainly some projecting going on here as I'm a
mostly-typed fan myself, but my sense is that the PHP user-space
community has already decided they want a robust typing system they can
use in most (but not all) cases. The engine should embrace that and
catch up, with a well thought-out approach to typing. If it takes a bit
longer to get certain features as a result of that attention to a
coherent roadmap, I am happy to make that trade-off.
--Larry Garfield
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