protected function getPrefixes(array $tagNames)
	{
		$prefixes = [];
		foreach ($tagNames as $tagName)
		{
			$pos = strpos($tagName, ':');
			if ($pos !== false)
			{
				$prefixes[substr($tagName, 0, $pos)] = 1;
			}
		}
		$prefixes = array_keys($prefixes);
		sort($prefixes);

		return $prefixes;
	}
protected function getPrefixes(array $tagNames)
	{
		$prefixes = [];
		foreach ($tagNames as $tagName)
		{
			$pos = strpos($tagName, ':');
			if ($pos !== false)
			{
				$prefixes[substr($tagName, 0, $pos)] = 1;
			}
		}
		$prefixes = array_keys($prefixes);
		sort($prefixes);

		return $prefixes;
	}
protected function getPrefixes ( array $ tagNames ) { $ prefixes = [ ] ; foreach ( $ tagNames as $ tagName ) { $ pos = strpos ( $ tagName , ':' ) ; if ( $ pos !== false ) { $ prefixes [ substr ( $ tagName , 0 , $ pos ) ] = 1 ; } } $ prefixes = array_keys ( $ prefixes ) ; sort ( $ prefixes ) ; return $ prefixes ; }
Extract and return the sorted list of prefixes used in given list of tag names

@param  string[] $tagNames
@return string[]
Extract and return the sorted list of prefixes used in given list of tag names