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Date: Thu, 11 Aug 2022 22:21:26 +0300
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To: Larry Garfield <larry@garfieldtech.com>
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Subject: Re: [PHP-DEV] [Concept] Extension methods
From: autaut03@gmail.com (Alex Wells)

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> On 11 Aug 2022, at 22:02, Larry Garfield <larry@garfieldtech.com> =
wrote:
>=20
> On Thu, Aug 11, 2022, at 1:59 PM, Alex Wells wrote:
>=20
>>>> Well, pipe operator is another option, but it=E2=80=99s got it=E2=80=99=
s 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 =
functions. Hence,=20
>>>> two different `map` method extensions can be imported in a single =
file=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 =
file,=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 =
clashes between=20
>>>> same method names, prefixes would be required
>>>=20
>>> Flipside: Pipe works on arrays and strings, which this would not. =
And arrays and strings are among the most common things to be chained in =
this 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 =
syntax 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
>>=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
>=20
> How feasible is that to implement?
>=20
>> Regarding the impression, I agree. I=E2=80=99m not sure if this is a =
problem=20
>> though, as this isn=E2=80=99t a problem in other languages. I=E2=80=99m=
 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 =
languages.=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.
>=20
> Numerous languages also included a pipe operator to handle this use =
case, so... =C2=AF\_(=E3=83=84)_/=C2=AF
>=20
> --Larry Garfield
>=20
> --
> PHP Internals - PHP Runtime Development Mailing List
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<https://www.php.net/unsub.php>
Well.. I think it=E2=80=99s the rest of the feature that is hard. =
Checking for types should be relatively trivial, as one could use the =
same logic for extension methods as is used when checking if an argument =
can be passed into a typed function parameter, but with strict_types=3D1. =
So for classes, enums & interfaces it=E2=80=99s instanceof; scalars and =
array - an exact type match with an exception of int value for float =
type; iterable/object/mixed also checked as a function parameter. It=E2=80=
=99s likely I=E2=80=99m missing some edge cases though :)=

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