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Date: Thu, 11 Aug 2022 14:02:26 -0500
To: "php internals" <internals@lists.php.net>
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Subject: Re: [PHP-DEV] [Concept] Extension methods
From: larry@garfieldtech.com ("Larry Garfield")

On Thu, Aug 11, 2022, at 1:59 PM, Alex Wells wrote:

>>> Well, pipe operator is another option, but it=E2=80=99s got it=E2=80=
=99s downsides=20
>>> compared to extension methods:
>>> - it's less versatile: extension methods are required to specify a=20
>>> type they=E2=80=99re extending, meaning they are methods, not functi=
ons. Hence,=20
>>> two different `map` method extensions can be imported in a single fi=
le=20
>>> (given they=E2=80=99re for different types - say one for `Collection=
`, the=20
>>> other for `array`), unlike regular functions. I believe it=E2=80=99s=
 common=20
>>> place to use both `Collection::map` and `array::map` in a single fil=
e,=20
>>> but that wouldn=E2=80=99t be possible or would require aliasing
>>> - it=E2=80=99s uglier: since it just uses functions, to avoid clashe=
s between=20
>>> same method names, prefixes would be required
>>=20
>> Flipside: Pipe works on arrays and strings, which this would not.  An=
d arrays and strings are among the most common things to be chained in t=
his way.  (Most Collection objects are just alternate OOPy syntax around=
 array_map and array_filter, at the end of the day.)  Pipe also doesn't =
give the impression that the method is "part of" the object (it's not), =
whereas extensions do, despite being effectively just an alternate synta=
x for a public function that takes the object as an argument.
>>=20
>> And functions can be easily namespaced.
>>=20
>> --Larry Garfield
>>=20
>> --
>> PHP Internals - PHP Runtime Development Mailing List
>> To unsubscribe, visit: https://www.php.net/unsub.php
>>=20
>
> Why would this not work on arrays and strings? The intention is the=20
> exact opposite: allow extension on (almost) all types allowed in PHP.=20
> That includes all scalars, object, iterable, array, mixed, all classes=
,=20
> interfaces & enums.=20

How feasible is that to implement?

> Regarding the impression, I agree. I=E2=80=99m not sure if this is a p=
roblem=20
> though, as this isn=E2=80=99t a problem in other languages. I=E2=80=99=
m aware it=E2=80=99s not=20
> a correct to compare PHP with other languages, but in this context PHP=20
> is facing a question that wasn=E2=80=99t much different for other lang=
uages.=20
> This is also easily solvable by introducing an extension member access=20
> operator - something like `->>`. Alternatively, an IDE can just=20
> highlight a method as being from an extension.

Numerous languages also included a pipe operator to handle this use case=
, so... =C2=AF\_(=E3=83=84)_/=C2=AF

--Larry Garfield