This document provides an overview of the Standard PHP Library (SPL) including common data structures like stacks, queues, heaps and iterators. It discusses how SPL extensions like SplSubject and SplObserver can be used to implement observer patterns. Various real-world open source projects using SPL are cited as examples. The document encourages involvement in improving and expanding SPL through code contributions and community engagement.

1. SPL IN THE WILD
The Good, the Bad and the Ugly

2. If you don’t know SPL
basics, this talk might go
fast for you.
Please rate me -
Feedback is good!

3. Why SPL?
What SPL?
How SPL?
A library of standard interfaces,
classes, and functions designed to
solve common programming
problems and allow engine
overloading

4. BUT ISN’T SPL AN EXTENSION?
 SPL is an extension
 SPL is a core extension
 SPL cannot be built shared
 SPL should not be turned off
 SPL is present in PHP since 5.0 (almost 5 years ago)
 As of 5.3, SPL cannot be turned off
If you don’t have SPL, whoever built your PHP is an idiot.

5. Don’t let friends use __autoload
AUTOLOAD

6. AUTOLOAD STACK ERR QUEUE
spl_autoload_register()
spl_autoload_unregister()
spl_autoload_call()
spl_autoload_functions()
 https://gist.github.com/221634

7. BEWARE THE WEIRDNESS
spl_autoload()
lowercase
relative paths
namespace aware
spl_autoload_extensions()
include the .
no spaces in between
comma separated string

8. IN THE WILD
Vanilla Forums
https://github.com/vanillaforums/Garden
https://github.com/vanillaforums/Garden/blob/23
d46ffec12624738fabb4d1917178b4a7872ffd/libra
ry/core/functions.general.php

9. What went wrong where
EXCEPTIONS

10. EXCEPTION CLASSES
LogicException
BadFunctionCall InvalidArgument Domain Length OutofRange
Exception Exception Exception Exception Exception
BadMethodCall
Exception

11. EXCEPTION CLASSES
RuntimeException
Unexpected
OutofBounds Overflow Range UnderflowE Value
Exception Exception Exception xception
Exception

12. IN THE WILD
ZF2
https://github.com/zendframework/zf2
http://ralphschindler.com/2010/09/15/exception-best-practices-in-php-5-3

13. Yes PHP has a file object
FILES

14. SPLFILEINFO
 Metadata about a file
 Returned by directory iterators
 Can set your own superclass for splfileinfo/splfileobject
 In the Wild
 phpcmc
 https://github.com/fqqdk/phpcmc/blob/master/tests/p
hpcmc/micro/PhpLinterTest.php

15. SPLFILEOBJECT
 Open file pointer
 Extends splfileinfo
In the Wild
Utils Plugin for CakePHP
 https://github.com/CakeDC/utils/blob/master/Mo
del/Behavior/CsvImportBehavior.php

16. Magic objects oh my
ARRAYS AS OBJECTS

17. SPECIFICALLY ARRAYOBJECT
 Implements ArrayAccess (with references)
 Implements Countable
 Implements IteratorAggregate
 Implements Serializable (since 5.3.0)
 And other methods that arrays can use (but not all)
 In the Wild
 Rapide Framework
 https://github.com/Hanse/rapide-
framework/blob/master/lib/Rapide/Utility/ArrayObject.php

18. Magic and organization
INTERFACES

19. QUICK TANGENT
Traversable
 (none)
Iterator
 https://github.com/tyohan/WordPress-MVC-
Framework/blob/11c4c550bf95bed9b142efa46200c9433
0350105/TPostList.php
IteratorAggregate
 https://github.com/lox/pheasant/blob/d3f4b0806eceb81e
0351a45d98eb1506134e6b56/lib/Pheasant/Identity.php

20. MORE CORE INTERFACES
ArrayAccess
 https://github.com/tidal/PEIP/blob/master/src/event/PEIP_
Event.php
Serializable
 https://github.com/shizzard/RAPIClient/blob/master/Help
er/Storage.php
Closure
 Do not use (seriously)

21. SPL - COUNTABLE
 Interface meaning “you can count me”
 Can be put on any class
 Makes count() magical
 Note this is NOT the same as iterator_count()
 https://github.com/ysbaddaden/php5-
redis/blob/master/lib/Redis/Servers.php

22. ITERATOR INTERFACES
 Outer Iterator
 Inner Iterator
 Seekable Iterator
 For examples, we’ll look at the iterator classes

23. SPLSUBJECT SPLOBSERVER
 Are you implementing the observer pattern in your code?
 Do you intend to have other people use your code/library in some way?
 Are you implementing something LIKE the observer pattern?
 In the Wild
 EmailLabs_Sync (SplSubject)
 https://github.com/sankovicmarko/EmailLabs_Sync/blob/master/li
brary/EmailLabs/Logger.php
 Frapi
 https://github.com/frapi/frapi/blob/master/src/frapi/library/PEAR/
HTTP/Request2/Observer/Log.php

24. Take a Drink …
ITERATORS

25. (RECURSIVE)FILTERITERATOR
 Abstract Class
 Has one method that must be implemented – accept – which should
return true or false
 Highly useful for many types of iteration
 https://github.com/nishimura/laiz/blob/master/laiz/builder/AutoIncludeFil
ter.php
 https://github.com/ralphschindler/PHPTools/blob/master/library/PHPToo
ls/Namespacer/RecursiveFilterIterator.php
FilterIterator OuterIterator Iterator Traversable

26. (RECURSIVE)ITERATORITERATOR
 Regular Class
 Stick in something that implements traversable
 Instant Iterator
 https://github.com/halfnelson/LINQ4PHP/blob/master/Iterators/Transfor
mIterator.php
 https://github.com/symfony/symfony/blob/master/src/Symfony/Compone
nt/Finder/Iterator/DepthRangeFilterIterator.php
IteratorIterator OuterIterator Iterator Traversable

27. (RECURSIVE)ARRAYITERATOR
 Regular Class
 Iterates an array – OR the public properties of an object! (neat trick –
dirty trick)
 https://github.com/diggin/Diggin_Service_Wedata/blob/master/src/Diggin
/Service/Wedata/Items.php
 https://github.com/Respect/Validation/blob/master/library/Respect/Valida
tion/ExceptionIterator.php
ArrayIter SeekableI ArrayAccess
Iterator Traversable and Countable
ator terator too!

28. APPENDITERATOR
 Keep stacking more iterators on the end with append
 https://github.com/WebToad/FashionPolice/blob/master/libs/Nette/Utils/
Finder.php
ParentIterator OuterIterator Iterator Traversable

29. LIMITITERATOR
 Regular Class
 Like mysql’s limit – pick your range and offset and foreach away!
 https://github.com/jasir/ComponentTreePanel/blob/master/ComponentT
reePanel.php
LimitIterator OuterIterator Iterator Traversable

30. FILESYSTEMITERATOR
 Extends directory iterator
 Lets you choose how to get data (just string names possible)
 https://github.com/KnpLabs/Gaufrette/blob/master/tests/Gaufrette/Adap
ter/LocalTest.php
FileSystemIterator DirectoryIterator Iterator Traversable

31. (RECURSIVE)CACHINGITERATOR
 Regular Class
 Manages another iterator by checking whether it has more elements
each time using a hasNext() method
 https://github.com/bshaffer/Donate-
Nashville/blob/master/plugins/sfPhpExcelPlugin/lib/PHPExcel/PHPExcel/
Worksheet/RowIterator.php
CachingIterator OuterIterator Iterator Traversable
RecursiveCach CachingIterator OuterIterator Iterator Traversable
ingIterator

32. (RECURSIVE)DIRECTORYITERATOR
 Regular Class
 Walk a Directory
 https://github.com/quentinhill/curator/blob/master/Curator/Project.php
 https://github.com/spidee/PHP-
Framework/blob/master/libs/Smarty/sysplugins/smarty_internal_utility.p
hp
DirectoryIterator SplFIieInfo Iterator Traversable
RecursiveDirectoryIteerator DirectoryIterator

33. RECURSIVETREEITERATOR
 Regular Class
 Can create an ascii graphic tree (seriously…)
 https://github.com/Respect/Validation/blob/master/library/Respect/Valida
tion/Exceptions/AbstractNestedException.php
RecursiveTr RecursiveItera
OuterIterator Iterator Traversable
eeIterator torIterator

34. (RECURSIVE)REGEXITERATOR
 Regular Class
 Filter an iterator by a regex
 Pick how you want it to match
 https://github.com/felipensp/php-
tools/blob/master/bughunter/bughunter.php
 https://github.com/lgunsch/victorycms-
core/blob/master/lib/utilities/Vcms-FileUtils.php
RegexIterator FilterIterator Iterator Traversable
RecursiveRegexIteerator RegexIterator

35. EMPTY AND INFINITE ITERATORS
 In the Wild – EmptyIterator
https://github.com/evilgeny/bob/blob/master/romir/projects/libraries/Bar
code/Mapper.class.php
 Infinite? Really only useful for testing
EmptyIterator Iterator Traversable
InfiniteIterator IteratorIterator Iterator Traversable

36. MORE EXIST
 ParentIterator
 NoRewindIterator
 MultipleIterator
 GlobIterator
 CallbackFilterIterator
 RecursiveCallbackFilterIterator

37. New ways of managing data
DATASTRUCTURES

38. DOUBLYLINKEDLISTS – CS LESSON
 ordered collection of values
 linked to each element before it
 linked to each element after it
 “doubly linked”
 PHP datastructure – a php object with a doublylinkedlist stored inside it

39. SPLDOUBLYLINKEDLIST
 Don’t use this
 Yes, that’s a terrible thing to say – but this is really nothing more then a
“base class” with little to recommend on its own
 Has a doublylinkedlist from C underneath instead of a hashtable – if you
know what that means you may find a real use for this (I have not)
 https://github.com/osebboy/Notification/blob/master/src/Notification/Di
spatcher.php

40. SPLSTACK
 Data is in LIFO
 Anything you need to iterate a lot
 Even cooler? Turn on the mode that will autodelete each item as you
process it
 Any Queue you need to push stuff onto and deal with in LIFO order
 https://github.com/rsesek/phalanx/blob/master/tasks/task_pump.php

41. SPLQUEUE
 Data is in FIFO
 Anything you need to iterate a lot
 Even cooler? Turn on the mode that will autodelete each item as you
process it
 Any Queue you need to push stuff onto and deal with in LIFO order
 https://github.com/matthewshafer/fauxThread/blob/master/src/fauxThre
adPool.php

42. HEAP – QUICK CS LESSON
 comparison function used to compare the new element to other
elements
 element is placed according to functions return value
 underlying algorithm does it with minimal comparisons
 PHP datastructure – a php object with a heap stored inside it

43. USING SPLHEAP
 This is an abstract class
 You need to compare elements
 https://github.com/ckwalsh/LibSprite
 https://github.com/ckwalsh/LibSprite/blob/master/src/php5_3/CKWalsh/
LibSprite/Util/Block/Heap/Width.php
 https://github.com/ckwalsh/LibSprite/blob/master/src/php5_3/CKWalsh/
LibSprite/Packer/GreedyHeap.php

44. SPLMINHEAP, SPLMAXHEAP
 These are concrete heap implementations, designed to grab the lowest
possible value out, or the highest possible
 https://github.com/tobyS/php-
snippets/blob/master/datastructures/bottom_k.php
 https://github.com/stormbreakerbg/A---A-Star--pathfinding-class-in-
PHP/blob/master/AStarWithHeap.php

45. SPLPRIORITYQUEUE
 Uses heap internally
 Is non-deterministic when identical priorities are used
 https://github.com/ss23/DeBot/blob/master/core/SplFIFOPriorityQueue.
php

46. SPLFIXEDARRAY
 You have a large amount of data, you know the final size, you need to
stick it into an array
 You’re not going to expand it past the final size
 This is not a small amount of data
 You might need it in non-sequential order but can handle having only
integers for keys
 https://github.com/cboden/gClient/blob/master/lib/gClient/Calendar/Cal
endar.php

47. SPLOBJECTSTORAGE
This can be used two ways
Objects can be keys in an array (with two
values)
As a Set (with one value)
 https://github.com/greggles/epm_project_management/blob/master/Que
ryPath/CssEventHandler.php

48. WHAT DO YOU WANT TO SEE IN SPL?
More standard interface?
More datastructures?
trees?
graphs?
More iterators? really? more?

49. GET INVOLVED
http://edit.php.net
Blog posts
Articles
Use SPL in the wild

50. CONTACT ME
 http://emsmith.net
 https://joind.in/6228
 auroraeosrose@gmail.com
 IRC – freenode – auroraeosrose
 #coapp and others