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Date: Tue, 16 Dec 2025 08:08:05 +0000
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CC: Matthew Weier O'Phinney <mweierophinney@gmail.com>,
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Subject: Re: [PHP-DEV] [RFC] Context Managers
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From: imsop.php@rwec.co.uk ("Rowan Tommins [IMSoP]")

(Replying to a few of you in one go, I hope the formatting is clear)=20

>>> we have changed the RFC to use =3D> instead=2E  So the new syntax is
>>>
>>> using (new CM() =3D> $cVar) {
>>>   // Do stuff here=2E
>>> }
>>>
>>
>> Going to be controversial here, but this is confusing, because it opera=
tes
>> in the exact opposite of every other usage of =3D> we have=2E=20
>
> I agree with Matthew=2E
>
> I think it makes more sense to reverse them, like this:
>
>     using ($cVar =3D> new CM()) {
>         // Do stuff here=2E
>     }


It took me a long time to figure out what you were both saying here, becau=
se to me the direction of the arrow seems to consistently indicate data flo=
w: you call the function, and data comes out; you enter the context, and a =
variable comes out=2E

But I think I see it now: you're treating the context variable like an arr=
ay key, that is somehow "bound to" the result=2E Except that's not what's h=
appening, otherwise we could just use "=3D"=2E


>I also agree with Matthew but the reversed proposed here looks very very
>awkward to me=2E I think the most natural thing is the =E2=80=9Cas=E2=80=
=9D but I may have
>missed the discussion on why it had to be changed=2E
>
>Thinking of foreach ($array as $value), an item from the array (left) is
>assigned to $value (right)=2E


This is the way to read the "as" syntax, yes; as I've said in a few places=
, a Context Manager is like an iterator that goes around once=2E


> That seems symmetrical to using (new Manager as
>$manager) where the instance (left) is assigned to the variable (right)=
=2E


This, however, is why it was changed: that is *not* what is happening=2E T=
he Context Manager is not assigned to the variable, it *produces a value* w=
hich is assigned to the variable=2E=20

Again, look at the foreach equivalence: you wouldn't write "foreach(new My=
Iterator as $iterator)", because it's not the iterator that ends up in the =
variable, it's the *items produced by* the iterator=2E=20

So you have "foreach(new MyIterator as $item)" and "using(new MyContextMan=
ager as $contextVar)"=2E=20

But evidently that is not obvious to readers=2E



My favourite among my own suggestions was "using($cValue from new CM())", =
but Larry didn't like the reversed order=2E I also suggested 'using(new CM(=
) for $cValue)", but I don't think that's as clear=2E=20

Perhaps there is some other word we can use? I suspect it would not need t=
o be fully reserved, as it's used in a very restricted context=2E

Or, perhaps there's something other than "using" that clues the reader int=
o "this object will be used to produce an arbitrary value" in the same way =
as "foreach=2E=2E=2Eas" does?


Rowan Tommins
[IMSoP]