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Subject: Re: [PHP-DEV] [Concept] Flip relative function lookup order (global, then
 local)
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From: rob@bottled.codes ("Rob Landers")

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On Fri, Aug 23, 2024, at 21:41, Rowan Tommins [IMSoP] wrote:
>=20
>=20
> On 23 August 2024 18:32:41 BST, Ilija Tovilo <tovilo.ilija@gmail.com> =
wrote:
> >IMO, 1. is too drastic. As people have mentioned, there are tools to
> >automate disambiguation. But unless we gain some other benefit from
> >dropping the lookup entirely, why do it?
>=20
> I can think of a few disadvantages of "global first":
>=20
> - Fewer code bases will be affected, but working out which ones is har=
der. The easiest migration will probably be to make sure all calls to na=
mespaced functions are fully qualified, as though it was "global only".
> - Even after the initial migration, users will have to watch out for n=
ew conflicting global functions. Again, this can be avoided by just pret=
ending it's "global only".=20
> - The engine won't be able to optimise calls where the name exists loc=
ally but not globally, because a userland global function could be defin=
ed at any time.
> - Unlike with the current way around, there's unlikely to be a use cas=
e for shadowing a namespaced name with a global one; it will just be a g=
otcha that trips people up occasionally.
>=20
> None of these seem like showstoppers to me, but since we can so easily=
 go one step further to "global only", and avoid them, why wouldn't we?=20
>=20
> Your answer to that seems to be that you think "global only" is a bigg=
er BC break, but I wonder how much difference it really makes. As in, ho=
w many codebases are using unqualified calls to reference a namespaced f=
unction, but *not* shadowing a global name?

I can think of more than one one-off script where I have written somethi=
ng like this:

namespace blah;

function read_and_process_file(): array {
}

function do_something(array $file): void { }

$file =3D read_and_process_file();
var_dump($file);
// die(); // debug
do_something($file);

If it were global only, then how would I call those files? namespace\rea=
d_and_process_file()?

That seems worse ergonomics and not better, for very little gain.


>=20
> Regards,
> Rowan Tommins
> [IMSoP]
>=20

=E2=80=94 Rob
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<!DOCTYPE html><html><head><title></title><style type=3D"text/css">p.Mso=
Normal,p.MsoNoSpacing{margin:0}</style></head><body><div>On Fri, Aug 23,=
 2024, at 21:41, Rowan Tommins [IMSoP] wrote:<br></div><blockquote type=3D=
"cite" id=3D"qt" style=3D""><div><br></div><div><br></div><div>On 23 Aug=
ust 2024 18:32:41 BST, Ilija Tovilo &lt;<a href=3D"mailto:tovilo.ilija@g=
mail.com">tovilo.ilija@gmail.com</a>&gt; wrote:<br></div><div>&gt;IMO, 1=
. is too drastic. As people have mentioned, there are tools to<br></div>=
<div>&gt;automate disambiguation. But unless we gain some other benefit =
from<br></div><div>&gt;dropping the lookup entirely, why do it?<br></div=
><div><br></div><div>I can think of a few disadvantages of "global first=
":<br></div><div><br></div><div>- Fewer code bases will be affected, but=
 working out which ones is harder. The easiest migration will probably b=
e to make sure all calls to namespaced functions are fully qualified, as=
 though it was "global only".<br></div><div>- Even after the initial mig=
ration, users will have to watch out for new conflicting global function=
s. Again, this can be avoided by just pretending it's "global only".&nbs=
p;<br></div><div>- The engine won't be able to optimise calls where the =
name exists locally but not globally, because a userland global function=
 could be defined at any time.<br></div><div>- Unlike with the current w=
ay around, there's unlikely to be a use case for shadowing a namespaced =
name with a global one; it will just be a gotcha that trips people up oc=
casionally.<br></div><div><br></div><div>None of these seem like showsto=
ppers to me, but since we can so easily go one step further to "global o=
nly", and avoid them, why wouldn't we?&nbsp;<br></div><div><br></div><di=
v>Your answer to that seems to be that you think "global only" is a bigg=
er BC break, but I wonder how much difference it really makes. As in, ho=
w many codebases are using unqualified calls to reference a namespaced f=
unction, but *not* shadowing a global name?<br></div></blockquote><div><=
br></div><div>I can think of more than one one-off script where I have w=
ritten something like this:<br></div><div><br></div><div>namespace blah;=
<br></div><div><br></div><div>function read_and_process_file(): array {<=
br></div><div>}<br></div><div><br></div><div>function do_something(array=
 $file): void { }</div><div><br></div><div>$file =3D read_and_process_fi=
le();<br></div><div>var_dump($file);<br></div><div>// die(); // debug<br=
></div><div>do_something($file);<br></div><div><br></div><div>If it were=
 global only, then how would I call those files? namespace\read_and_proc=
ess_file()?<br></div><div><br></div><div>That seems worse ergonomics and=
 not better, for very little gain.</div><div><br></div><div><br></div><b=
lockquote type=3D"cite" id=3D"qt" style=3D""><div><br></div><div>Regards=
,<br></div><div>Rowan Tommins<br></div><div>[IMSoP]<br></div><div><br></=
div></blockquote><div><br></div><div id=3D"sig121229152">=E2=80=94 Rob<b=
r></div></body></html>
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