Request for Comments: SPL Improvements: Data Structures

• Version: 1.0
• Date: 2012-02-07
• Author: Levi Morrison levim@php.net
• Status: Work-in-progress

The data structures in the SPL are flawed in many ways.

Inconsistent behavior between structures. The data-structures are inconsistent in how they act when in the same situation. Consider the following example where an SplDoublyLinkedList and an SplFixedArray encounter the same problem: an index greater than the size of the container was accessed.

<?php
try {
    $linkedList = new SplDoublyLinkedList();
    $linkedList[1];
} catch(Exception $error) {
    echo get_class($error) . ': ' . $error->getMessage(). "\n";
}
try {
    $fixedArray = new SplFixedArray();
    $fixedArray[1];
} catch(Exception $error) {
    echo get_class($error) . ': ' . $error->getMessage(). "\n";
}
?>

The result:

OutOfRangeException: Offset invalid or out of range
RuntimeException: Index invalid or out of range

They do not throw the same exception. Furthermore, SplDoublyLinkedList throws an exception that inherits from LogicException when it is not a logical exception but a runtime one.

Poor API.

SplObjectStorage.

We fix it.