This hardly seems a fair comparison between the two examples, size-for-size. As noted, generators are forward-only, meaning that it should be compared to an iterator with a dummy rewind function defined. Also, to be fair, since the iterator throws an exception, shouldn't the generator example also throw the same exception? The code comparison would become more like this:
<?php
function getLinesFromFile($fileName) {
if (!$fileHandle = fopen($fileName, 'r')) {
throw new RuntimeException('Couldn\'t open file "' . $fileName . '"');
}
while (false !== $line = fgets($fileHandle)) {
yield $line;
}
fclose($fileHandle);
}
class LineIterator implements Iterator {
protected $fileHandle;
protected $line;
protected $i;
public function __construct($fileName) {
if (!$this->fileHandle = fopen($fileName, 'r')) {
throw new RuntimeException('Couldn\'t open file "' . $fileName . '"');
}
}
public function rewind() { }
public function valid() {
return false !== $this->line;
}
public function current() {
return $this->line;
}
public function key() {
return $this->i;
}
public function next() {
if (false !== $this->line) {
$this->line = fgets($this->fileHandle);
$this->i++;
}
}
public function __destruct() {
fclose($this->fileHandle);
}
}
?>
The generator is still obviously much shorter, but this seems a more reasonable comparison.
