README

This library provides a set of immutable collection classes that allow for an consistent, object oriented, fluent style of manipulating data collections. It is mainly inspired by LINQ from C# and the Java Stream API.

Installing

composer require jcstrandburg\demeter

Usage

Vanilla PHP:

$x = array_slice(
  array_map(
    function ($x) {return $x * 2;},
    array_filter([1, 2, 3, 4, 5], function ($x) {return $x % 2 == 1;})),
  0, 2);

With Demeter:

use function Jcstrandburg\Demeter\sequence;
use Jcstrandburg\Demeter\Lambda;

$x = sequence([1, 2, 3, 4, 5])
  ->filter(Lambda::isOdd())
  ->map(Lambda::multiplyBy(2))
  ->take(2);

Features

Version History

Unreleased

0.8

Added

• Extensions static class for extension method support

0.7

Changes

• All collection classes now implement IteratorAggregate instead of extending IteratorIterator
• GroupedCollection::getGroupKeys now returns a Collection instead of an array
• It is now possible to safely perform concurrent iterations over the same Sequence or derivations thereof.

For example, if $x = sequence([1,2,3,4]);

Before: $x->zip($x->map(Lambda::plus(1)), Lambda::add())->toArray() == [3,6]

Now: $x->zip($x->map(Lambda::plus(1)), Lambda::add())->toArray() == [3,5,7,9]

Removed

• LazyRewindableIterator has been replaced with an internal implementation

Added

• as_iterator utility function

Deprecated

• as_traversable - use as_iterator instead

0.6

Fixed

• Call the parent constructor from ArrayGroupedCollection

Changed

• Breaking: Convert GroupedCollection to an interface, with the existing implementation becoming ArrayGroupedCollection
• Breaking: Convert Grouping to an interface, with the existing implementation becoming ArrayGrouping
• Make Collection extend Countable
• xrange now returns a Sequence

Added

• Lambda::constant
• Lambda::toArray
• Lambda::getGroupKey
• Sequence::zip
• Sequence::chunk
• Sequence::join
• Sequence::implode

0.5

Changed

• Breaking: Changed the behavior of HashSet so that it acts like a proper set (hashing is used for buckets but not equality comparisons)
• Breaking: Convert Sequence to an interface, with the existing implementation becoming LazySequence
• Breaking: Convert Collection to an interface, with the existing implementation becoming ArrayCollection
• Breaking: Convert Dictionary to an interface, with the existing implementation becoming ArrayDictionary
• Breaking: Functions previously returning HashSet now return Set

Added

• Introduce Set interface which HashSet implements
• Sequence::except and Sequence::intersect
• Lambda utility class
• dictionary and set factory functions

0.4

Added

• HashMap::addMany
• HashMap::removeMany
• Sequence::toDictionary
• Dictionary

0.3

Changed

• sequence and collect now will return their argument unmodified if is already of the correct type

Added

• HashSet
• Sequence::asSet
• Sequence::first
• Sequence::firstOrNull
• Sequence::last
• Sequence::lastOrNull
• Sequence::single
• Sequence::singleOrNull

0.2

Added

• Sequence::groupBy
• GroupedCollection
• Grouping

0.1

Added

• Sequence
• Collection
• Various utility functions
• LazyRewindableIterator
• MappedIterator
• SkipWhileIterator
• TakeWhileIterator

License

This project is licensed under the MIT License - see the LICENSE.md file for details