An exercise of implementing a higher order if.

readme.md

Higher Order If

Because of short closures, I ended up wondering if Higher Order Ifs are nice to read.

I don't really recommend this, it's just a fun exercise to help me figure out how Laravel did the Higher Order stuff. 😅

public static function boot()
{
    static::created(function ($user) {
       if ($user->isSuperAdmin()) {
            $task->activate();
        }
    });
}

to

# Using the "Iffable"
public static function boot()
{
    static::created(fn ($user) => $user->if->isSuperAdmin()->activate());
}

# or
public static function boot()
{
    static::created(fn ($user) => $user->if()->isSuperAdmin()->activate());
}

HigherOrderIfProxy.php

<?php

namespace App;

use Illuminate\Support\Traits\ForwardsCalls;

class HigherOrderIfProxy
{
    use ForwardsCalls;

    public function __construct($target)
    {
        $this->target = $target;
    }

    public function __call($method, $parameters = [])
    {
        if ($this->forwardCallTo($this->target, $method, $parameters)) {
        return $this->target;
        }

        return new class {
            public function __call($method, $parameters =[])
            {
                // do nothing!!!
            }
        };
    }
}

HigherOrderIfProxyTest.php

<?php

namespace Tests\Feature;

use App\HigherOrderIfProxy;
use PHPUnit\Framework\TestCase;

class HigherOrderIfProxyTest extends TestCase
{
    function test_do()
    {
        $mock = new MockClass;
        $hasRan = false;

        $this->assertFalse($hasRan);

        $mock->do(function () use (&$hasRan) {
            $hasRan = true;
        });

        $this->assertTrue($hasRan);
    }

    function test_if_passes()
    {
        $mock = new MockClass;
        $hasRan = false;

        $this->assertFalse($hasRan);

        $mock->if()->isTrue()->do(function () use (&$hasRan) {
            $hasRan = true;
        });

        $this->assertTrue($hasRan);
    }

    function test_if_fails()
    {
        $mock = new MockClass;
        $hasRan = false;

        $this->assertFalse($hasRan);

        $mock->if()->isFalse()->do(function () use (&$hasRan) {
            $hasRan = true;
        });

        $this->assertFalse($hasRan);
    }
}

class MockClass
{
    public function if($closure = null)
    {
        return new HigherOrderIfProxy($this);
    }

    public function isTrue()
    {
        return true;
    }

    public function isFalse()
    {
        return false;
    }

    public function do($closure)
    {
        $closure->__invoke();
    }
}

Iffable.php

<?php

namespace App;

trait Iffable
{
    public function getIfAttribute()
    {
        return new HigherOrderIfProxy($this);
    }
    
    public function if()
    {
        return new HigherOrderIfProxy($this);
    }
}