Name: traversable-iterator
Owner: Wikimedia Deutschland e.V.
Description: Turn Traversable objects into Iterators. Fixed version of the native IteratorIterator
Created: 2017-06-17 16:50:47.0
Updated: 2017-06-17 17:17:21.0
Pushed: 2018-02-03 08:52:10.0
Homepage: null
Size: 16
Language: PHP
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Iterator that can be constructed from Traversable objects.
Can be seen as a fixed version of IteratorIterator (which is used internally). IteratorIterator
behaves in unexpected ways when constructed from an IteratorAggregate: it only calls getIterator
once rather than once per iteration, which is what happens when you traverse the IteratorAggregate
directly. In other words: looping over an IteratorIterator that contains a IteratorAggregate yields
different behaviour than looping over the IteratorAggregate itself. This is unexpected and can be
problematic. For instance when the IteratorAggregate contains a Generator (which happens often),
looping over the IteratorIterator more than once will cause an error due to the Generator not
being rewindable.
Example of how IteratorIterator fails:
ratorAggregate = new class() implements \IteratorAggregate {
public function getIterator() {
yield 'a';
yield 'b';
yield 'c';
}
rator = new IteratorIterator( $iteratorAggregate );
ach ( $iterator as $value ) {}
ach ( $iterator as $value ) {} // Exception: Cannot rewind a generator that was already run
This exception, and more generally difference in behaviour, does not occur when using TraversableIterator.
To add this package as a local, per-project dependency to your project, simply add a
dependency on wmde/traversable-iterator to your project's composer.json file.
Here is a minimal example of a composer.json file that just defines a dependency on
Traversable Iterator 1.x:
"require": {
"wmde/traversable-iterator": "~1.0"
}
For a full CI run
composer ci
For tests only
composer test
For style checks only
composer cs