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Subject: [PHP-DEV] Uniform Function Call Syntax
Thread-Topic: Uniform Function Call Syntax
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Date: Fri, 4 Apr 2025 01:52:01 +0000
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From: yakov.lipkovich@gmail.com (Yakov Lipkovich)

Hello,=0A=
=0A=
I would like to gather interest in adding Uniform Function Call Syntax (UFC=
S) to the PHP language. In short, it allows to call any static function `f(=
$a)` as `$a->f(...)`. The `...` is required because not all functions have =
the desired parameter in the first position. Outlined below are some benefi=
ts of this syntax.=0A=
=0A=
It allows for chaining of function calls that otherwise would look ugly. A =
common pattern is filtering and mapping arrays:=0A=
```php=0A=
$arr =3D [1, 2, -3, 4, 0, 5];=0A=
$filtered =3D \array_filter($arr, fn ($x) =3D> $x > 0);=0A=
$result =3D \array_map(fn ($x) =3D> $x * 2, $filtered);=0A=
\var_dump($result);=0A=
```=0A=
This can be written more eloquently:=0A=
```php=0A=
[1, 2, -3, 4, 0, 5]=0A=
        ->\array_filter(..., fn ($x) =3D> $x > 0)=0A=
        ->\array_map(fn ($x) =3D> $x * 2, ...)=0A=
        ->\var_dump(...);=0A=
```=0A=
=0A=
Another use case is for extension functions:=0A=
```php=0A=
class Cat=0A=
{=0A=
        public function __construct(public string $name) {}=0A=
       =0A=
        public function meow(): self=0A=
        {=0A=
                echo "{$this->name} meowed\n";=0A=
                return $this;=0A=
        }=0A=
       =0A=
        public function lickPaw(): self=0A=
        {=0A=
                echo "{$this->name} licked paw\n";=0A=
                return $this;=0A=
        }=0A=
}=0A=
=0A=
class CatExtension=0A=
{=0A=
        public static function scratch(Cat $cat): Cat=0A=
        {=0A=
                echo "{$cat->name} scratched\n";=0A=
                return $cat;=0A=
        }=0A=
}=0A=
=0A=
$cat =3D (new Cat('Tabby'))=0A=
        ->meow()=0A=
        ->(CatExtension::scratch)(...)=0A=
        ->lickPaw();=0A=
```=0A=
=0A=
For my proposal, only static functions need to be supported, but I don't se=
e why non-static functions can't be supported. One thing I'm unsure of is w=
hat happens if an imported static function has the same name as a member fu=
nction.=0A=
=0A=
The Wikipedia page has a bit more details, as well as examples of languages=
 which implement this syntax: https://en.wikipedia.org/wiki/Uniform_Functio=
n_Call_Syntax.=0A=
=0A=
Please let me know your questions, opinions, and feedback.=0A=
=0A=
Regards,=0A=
=0A=
Yakov=