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Date: Fri, 07 Mar 2025 09:39:33 +0000
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Subject: Re: [PHP-DEV] PHP True Async RFC
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From: imsop.php@rwec.co.uk ("Rowan Tommins [IMSoP]")



On 6 March 2025 19:07:34 GMT, Larry Garfield <larry@garfieldtech=2Ecom> wr=
ote:
>It is literally the same argument for "pass the DB connection into the co=
nstructor, don't call a static method to get it" or "pass in the current us=
er object to the method, don't call a global function to get it=2E"  These =
are decades-old discussions with known solved problems, which all boil down=
 to "pass things explicitly=2E"

I think the counterargument to this is that you wouldn't inject a service =
that implemented a while loop, or if statement=2E I'm not even sure what mo=
cking a control flow primitive would mean=2E

Similarly, we don't pass around objects representing the "try context" so =
that we can call "throw"as a method on them=2E I'm not aware of anybody com=
plaining that they can't mock the throw statement as a consequence, or want=
ing to work with multiple "try contexts" at once and choose which one to th=
row into=2E

A lexically scoped async{} statement feels like it could work similarly: t=
he language primitive for "run this code in a new fiber" (and I think it sh=
ould be a primitive, not a function or method) would look up the stack for =
an open async{} block, and that would be the "nursery" of the new fiber=2E =
[You may not like that name, but it's a lot less ambiguous than "context", =
which is being used for at least two different things in this discussion=2E=
]

Arguably this is even needed to be "correct by construction" - if the user=
 can pass around nurseries, they can create a child fiber that outlives its=
 parent, or extend the lifetime of one nursery by storing a reference to it=
 in a fiber owned by a different nursery=2E If all they can do is spawn a f=
iber in the currently active nursery, the child's lifetime guaranteed to be=
 no longer than its parent, and that lifetime is defined rigidly in the sou=
rce code=2E

Rowan Tommins
[IMSoP]