chh/funk

A minimal functional programming library for PHP

dev-master 2012-10-13 20:29 UTC

This package is not auto-updated.

Last update: 2020-04-03 16:26:47 UTC


README

Funk is a minimal functional library for PHP.

It's a collection of some things, I've felt the need for in many projects:

  • Dealing with Currying, memoizing and limiting calls to functions (Funk\Func).
  • Common collection operators which deal in a uniform way with both arrays and Iterators (Funk\Collection).
  • A tight wrapper around casting operations, which also deals with casting objects to scalars (Funk\Type).

Install

Install with Composer:

php composer.phar require chh/funk:*@dev

Then require vendor/autoload.php in your application.

Collection

The Funk\Collection class wraps a PHP iterable value and provides methods to manipulate it. The collection provides nearly all operations using Iterators and exposes this iterator via getIterator (also implements IteratorAggregate). That means that nearly all operations are lazy evaluated.

You can see this in action, if you wrap a PDO statement in a collection and then call map. This wraps the PDO Statement in a special "MappingIterator", which applies the callback function on each element and yields the callback's return value. But this happens only when the "MappingIterator" is iterated, until then nothing happens.

Example:

<?php

use Funk\Collection,
    Funk\Collection\Operator as op;

echo (new Collection(range(0, 20)))
    ->keep(function($x) { return $x > 5; })
    ->remove(op::gt(7))
    ->map(function($val) { return strval($val); })
    ->join(' ');

Everywhere where the argument is predicate the operation takes several different values with different characteristics:

  • An operator shortcut, which is an instance of the Operator class. Instances can be conveniently created by calling the operator as static method on this class. Valid operators include: is, eq, gt, gte, lt and lte.
  • Value, which is then compared against the current iterator's value by using ===.
  • Callback, the return value is used.
  • Null, which translates to $value == true.

__construct($iterable = null)

dup()

extend($value)

append($value)

map($fn)

reduce($callback, $initial = null)

count()

match($pattern)

asArray($assoc = true)

slice($offset, $count = -1)

join($glue = '')

tap($callback, $arguments = array())

all($predicate = null)

some($predicate = null)

compact($callback = null)

attr($attribute)

item($offset)

invoke($method, $arguments = array())

isEmpty($predicate = null)

reverse()

keep($predicate)

remove($predicate)

Casting

Example:

<?php

use Funk\Type;

class Foo
{
    function __toInt()
    {
        return 42;
    }
}

echo Type::intval(new Foo) + 1;
# Output:
# 43