Functional PHP: Functional primitives for PHP

Works with arrays and everything implementing interface Traversable
Consistent interface: first parameter is always the collection, than the callback. Callbacks always get value, key, collection passed
Calls 5.3 closures as well as traditional callbacks
C implementation for performance but compatible userland implementation is packaged if you can’t install PHP extensions
All functions reside in namespace Functional to not conflict with any other extension or library

TODO

Native implementation of Functional\pluck() shows slightly different behavior when dealing with private/protected properties
Implement Functional\curry() and related objects natively
Test reference handling
Add package.xml to build with pecl

Installation

Install native extension

cd functional-php/extension/
phphize
./configure
make
sudo make install

Use userland extension

<?php
include 'path/to/functional-php/src/Functional/_import.php';

Everytime you want to work with Functional PHP and not reference the fully qualified name, add use Functional as F; on top of your PHP file.

Overview

Functional\curry()

Functional\curry(callback $callback, [mixed $arg1, [mixed $arg2], ...])

<?php
use Functional as F;

$items = F\each(array('a1', 'a2'), F\curry('str_replace', 'a', 'b', F\arg(1))); // b1, b2

Functional\all() & Functional\invoke()

Functional\all(array|Traversable $collection, callable $callback)

Functional\invoke(array|Traversable $collection, string $methodName[, array $methodArguments])

<?php
use Functional as F;

// If all users are active, set them all inactive
if (F\all($users, function($user, $collectionKey, $collection) {return $user->isActive();})) {
    F\invoke($users, 'setActive', array(true));
}

Functional\any()

Functional\any(array|Traversable $collection, callable $callback)

<?php
use Functional as F;

if (F\any($users, function($user, $collectionKey, $collection) use($me) {return $user->isFriendOf($me);})) {
    // One of those users is a friend of me
}

Functional\none()

Functional\none(array|Traversable $collection, callable $callback)

<?php
use Functional as F;

if (F\none($users, function($user, $collectionKey, $collection) {return $user->isActive();})) {
    // Do something with a whole list of inactive users
}

Functional\reject() & Functional\select()

Functional\select(array|Traversable $collection, callable $callback)

Functional\reject(array|Traversable $collection, callable $callback)

<?php
use Functional as F;

$fn = function($user, $collectionKey, $collection) {
    return $user->isActive();
};
$activeUsers = F\select($users, $fn);
$inactiveUsers = F\reject($users, $fn);

Functional\pluck()

Fetch a single property from a collection of objects.

Functional\pluck(array|Traversable $collection, string $propertyName)

<?php
use Functional as F;

$names = F\pluck($users, 'name');

Functional\reduce_left() & Functional\reduce_right()

Applies a callback to each element in the collection and reduces the collection to a single scalar value. Functional\reduce_left() starts with the first element in the collection, while Functional\reduce_right() starts with the last element.

Functional\reduce_left(array|Traversable $collection, callable $callback[, $initial = null]) Functional\reduce_right(array|Traversable $collection, callable $callback[, $initial = null])

<?php
use Functional as F;

// $sum will be 64 (2^2^3)
$sum = F\reduce_left(array(2, 3), function($value, $key, $collection, $reduction) {
    return $reduction ^ $value;
}, 2);

// $sum will be 512 (2^3^2)
$sum = F\reduce_right(array(2, 3), function($value, $key, $collection, $reduction) {
    return $reduction ^ $value;
}, 2);

Additional functions:

Functional\each(array|Traversable $collection, callable $callback) Applies a callback to each element
Functional\map(array|Traversable $collection, callable $callback) Applies a callback to each element in the collection and collects the return value

pierrejoye/functional-php