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Date: Fri, 07 Nov 2025 22:58:34 +0000
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Subject: =?US-ASCII?Q?Re=3A_=5BPHP-DEV=5D_Pre-RFC_proposal=3A_opt-in_?=
 =?US-ASCII?Q?implicit_interfaces_/_structural_typing?=
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From: imsop.php@rwec.co.uk ("Rowan Tommins [IMSoP]")

On 7 November 2025 21:34:56 GMT, Larry Garfield <larry@garfieldtech=2Ecom> =
wrote:
>__toString() is *old*=2E  It may go all the way back to 5=2E0, but it was=
 there at least as of 5=2E2=2E  The problem is that there was no way to typ=
e against it=2E=20

I know all that=2E I've just never understood why you would *want* to type=
 against it=2E  The only thing you can do with that knowledge is turn the o=
bject into a string, so why not just ask for a string in the first place?

But I apologise for drifting off topic; the relevant point is that it work=
s exactly how the proposed implicit interfaces would, so whatever reasoning=
 was used for it might serve a useful example for other potential uses=2E I=
f nothing else, being able to say "it's a built-in implicit interface" woul=
d be less confusing than explaining it as a magical special case=2E

Who knows, maybe there are people wishing they could type against other ma=
gic methods, who could do so by declaring their own implicit interfaces=2E


As I say, I'm personally much more interested in highly explicit code, so =
am more likely to go completely the opposite direction: use an *empty inter=
face*, where the only thing you're doing is "tagging" a class as intended f=
or a particular purpose=2E

But, I know there are people who like "duck typing", and implicit interfac=
es or structural typing give a way to formalise that, so I can see value fo=
r those people=2E



Rowan Tommins
[IMSoP]