and_where_open() / or_where_open() auto removal example

where.php

<?php defined('SYSPATH') or die('No direct script access.');

abstract class Database_Query_Builder_Where extends Kohana_Database_Query_Builder_Where {

	/**
	 * Closes an open "AND WHERE (...)" grouping.
	 *
	 * @return  $this
	 */
	public function and_where_close()
	{
		$copy = end($this->_where);
		
		if (end($copy) === '(')
		{
			array_pop($this->_where);
		}
		else
		{
			$this->_where[] = array('AND' => ')');
		}
		
		return $this;
	}

	/**
	 * Closes an open "OR WHERE (...)" grouping.
	 *
	 * @return  $this
	 */
	public function or_where_close()
	{
		$copy = end($this->_where);
		
		if (end($copy) === '(')
		{
			array_pop($this->_where);
		}
		else
		{
			$this->_where[] = array('OR' => ')');
		}
		
		return $this;
	}

}