PHP code example of widmogrod / php-functional

    
        
<?php
require_once('vendor/autoload.php');

/* Start to develop here. Best regards https://php-download.com/ */

    

widmogrod / php-functional example snippets

use Widmogrod\Functional as f;
use Widmogrod\Primitive\Listt;

$list = f\fromIterable([
   ['id' => 1, 'name' => 'One'],
   ['id' => 2, 'name' => 'Two'],
   ['id' => 3, 'name' => 'Three'],
]);

$result = $list->map(function($a) {
    return $a['id'] + 1;
});

assert($result === f\fromIterable([2, 3, 4]));

use Widmogrod\Functional as f;
use Widmogrod\Primitive\Listt;

$listA = f\fromIterable([
    function($a) {
        return 3 + $a;
    },
    function($a) {
        return 4 + $a;
    },
]);
$listB = f\fromIterable([
    1, 2
]);

$result = $listA->ap($listB);

assert($result === f\fromIterable([4, 5, 5, 6]));

use Widmogrod\Monad\Maybe;
use Widmogrod\Primitive\Listt;

$data = [
    ['id' => 1, 'meta' => ['images' => ['//first.jpg', '//second.jpg']]],
    ['id' => 2, 'meta' => ['images' => ['//third.jpg']]],
    ['id' => 3],
];

// $get :: String a -> Maybe [b] -> Maybe b
$get = function ($key) {
    return f\bind(function ($array) use ($key) {
        return isset($array[$key])
            ? Maybe\just($array[$key])
            : Maybe\nothing();
    });
};

$result = f\fromIterable($data)
    ->map(Maybe\maybeNull)
    ->bind($get('meta'))
    ->bind($get('images'))
    ->bind($get(0));

assert(f\valueOf($result) === ['//first.jpg', '//third.jpg', null]);

use Widmogrod\Functional as f;
use Widmogrod\Monad\Either;

function read($file)
{
    return is_file($file)
        ? Either\Right::of(file_get_contents($file))
        : Either\Left::of(sprintf('File "%s" does not exists', $file));
}

$concat = f\liftM2(
    read(__DIR__ . '/e1.php'),
    read('aaa'),
    function ($first, $second) {
        return $first . $second;
    }
);

assert($concat instanceof Either\Left);
assert($concat->extract() === 'File "aaa" does not exists');

use Widmogrod\Monad\IO as IO;
use Widmogrod\Functional as f;

// $readFromInput :: Monad a -> IO ()
$readFromInput = f\mcompose(IO\putStrLn, IO\getLine, IO\putStrLn);
$readFromInput(Monad\Identity::of('Enter something and press <enter>'))->run();

use Widmogrod\Monad\Writer as W;
use Widmogrod\Functional as f;
use Widmogrod\Primitive\Stringg as S;

$data = [1, 10, 15, 20, 25];

$filter = function($i) {
    if ($i % 2 == 1) {
        return W::of(false, S::of("Reject odd number $i.\n"));
    } else if($i > 15) {
      return W::of(false, S::of("Reject $i because it is bigger than 15\n"));
    }

    return W::of(true);
};

list($result, $log) = f\filterM($filter, $data)->runWriter();

use Widmogrod\Monad\Reader as R;
use Widmogrod\Functional as f;

function hello($name) {
    return "Hello $name!";
}

function ask($content)
{
    return R::of(function($name) use($content) {
        return $content.
               ($name == 'World' ? '' : ' How are you?');
    });
}

$r = R\reader('hello')
      ->bind('ask')
      ->map('strtoupper');

assert($r->runReader('World') === 'HELLO WORLD!')

assert($r->runReader('World') === 'HELLO GILLES! HOW ARE YOU?')

$state = [
    'productsCount' => 0,
    'products' => [],
];

$scenario =
    Given('Product in cart', $state)
        ->When("I add product 'coca-cola'")
        ->When("I add product 'milk'")
        ->Then("The number of products is '2'");

$result = $scenario->Run([
    "/^I add product '(.*)'/" => function ($state, $productName) {
        $state['productsCount'] += 1;
        $state['products'][] = $productName;

        return $state;
    },
], [
    "/^The number of products is '(\d+)'/" => function ($state, int $expected) {
        return $state['productsCount'] === $expected;
    },
]);

$calc = mul(
    sum(int(2), int(1)),
    sum(int(2), int(1))
);

$expected = '((2+1)^2)';

$result = foldFree(compose(interpretPrint, optimizeCalc), $calc, Identity::of);
$this->assertEquals(
    Identity::of(Stringg::of($expected)),
    $result
);

$result = Identity::of(1)
    ->bind(function ($a) {
        return Identity::of(3)
            ->bind(function ($b) use ($a) {
                return Identity::of($a + $b)
                    ->bind(function ($c) {
                        return Identity::of($c * $c);
                    });
            });
    });

$this->assertEquals(Identity::of(16), $result);

$result = doo(
    let('a', Identity::of(1)),
    let('b', Identity::of(3)),
    let('c', in(['a', 'b'], function (int $a, int $b): Identity {
        return Identity::of($a + $b);
    })),
    in(['c'], function (int $c): Identity {
        return Identity::of($c * $c);
    })
);

assert($result === Identity::of(16));

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